gradle wrapper should not require bash

Version 2.0.3

.drone.yml

@@ -0,0 +1,9 @@
+kind: pipeline
+name: default
+
+steps:
+- name: test
+  image: adoptopenjdk/openjdk8:alpine
+  commands:
+  - ./gradlew assemble
+  - ./gradlew check

.editorconfig

@@ -0,0 +1,7 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+indent_size = 4

.gitignore

@@ -5,6 +5,7 @@
 ### Gradle ###
 .gradle
 build/
+classes/
 
 # Ignore Gradle GUI config
 gradle-app.setting

.travis.yml

@@ -1,2 +1,10 @@
 language: java
+sudo: false # faster builds
+jdk:
+  - oraclejdk8
 
+before_install:
+  - pip install --user codecov
+
+after_success:
+  - codecov

CONTRIBUTING.md

@@ -0,0 +1,24 @@
+# Contributing
+
+We love pull requests from everyone. Please be nice and forgive us
+if we can't process your request right away.
+
+Fork, then clone the repo:
+
+    git clone git@github.com:your-username/Jabit.git
+
+Make sure the tests pass:
+
+    ./gradlew test
+
+Make your change. Add tests for your change. Make the tests pass:
+
+    ./gradlew test
+
+Push to your fork and [submit a pull request][pr].
+
+[pr]: https://github.com/Dissem/Jabit/compare/
+
+Unfortunately we can't always answer right away, so we ask you to have
+some patience. Then we may suggest some changes or improvements or
+alternatives.

README.md

@@ -1,9 +1,32 @@
-Jabit [![Build Status](https://travis-ci.org/Dissem/Jabit.svg?branch=master)](https://travis-ci.org/Dissem/Jabit)
+Jabit
 =====
+[![Maven Central](https://maven-badges.herokuapp.com/maven-central/ch.dissem.jabit/jabit-core/badge.svg)](https://maven-badges.herokuapp.com/maven-central/ch.dissem.jabit/jabit-core)
+[![Javadoc](https://javadoc-emblem.rhcloud.com/doc/ch.dissem.jabit/jabit-core/badge.svg)](http://www.javadoc.io/doc/ch.dissem.jabit/jabit-core)
+[![Apache 2](https://img.shields.io/badge/license-Apache_2.0-blue.svg)](https://raw.githubusercontent.com/Dissem/Jabit/master/LICENSE)
+[![Visit our IRC channel](https://img.shields.io/badge/irc-%23jabit-blue.svg)](https://kiwiirc.com/client/irc.freenode.net/#jabit)
 
-A Java implementation for the Bitmessage protocol. To build, use command `gradle build` or `./gradlew build`.
+A Java implementation for the Bitmessage protocol. To build, use command `./gradlew build`.
 
-Please note that development is still heavily in progress, and I will break the database a lot until it's ready for prime time.
+Please note that it still has its limitations, but the API should now be stable. Jabit uses Semantic Versioning, meaning as long as the major version doesn't change, nothing should break if you update.
+
+Be aware though that this doesn't necessarily applies for SNAPSHOT builds and the development branch, notably when it comes to database updates. _In other words, they may break your installation!_ 
+
+#### Master
+[![Build Status](https://travis-ci.org/Dissem/Jabit.svg?branch=master)](https://travis-ci.org/Dissem/Jabit) 
+[![Code Quality](https://img.shields.io/codacy/e9938d2adbb74a0db553115bef692ff3/master.svg)](https://www.codacy.com/app/chrigu-meyer/Jabit/dashboard?bid=3144281)
+[![Test Coverage](https://codecov.io/github/Dissem/Jabit/coverage.svg?branch=master)](https://codecov.io/github/Dissem/Jabit?branch=master)
+
+#### Develop
+[![Build Status](https://travis-ci.org/Dissem/Jabit.svg?branch=develop)](https://travis-ci.org/Dissem/Jabit?branch=develop) 
+[![Code Quality](https://img.shields.io/codacy/e9938d2adbb74a0db553115bef692ff3/develop.svg)](https://www.codacy.com/app/chrigu-meyer/Jabit/dashboard?bid=3144279)
+[![Test Coverage](https://codecov.io/github/Dissem/Jabit/coverage.svg?branch=develop)](https://codecov.io/github/Dissem/Jabit?branch=develop)
+
+Upgrading
+---------
+
+Please be aware that Version 2.0.0 has some breaking changes, most notably in the repository implementations -- please take special care when upgrading them. If you don't implement your own repositories, you should be able to quickly find and fix any compilation errors caused by the few other breaking changes. 
+
+There is also a new network handler which comes highly recommended. If you're having any network problems, please make sure you use `NioNetworkHandler` instead of the now deprecated `DefaultNetworkHandler`.
 
 Security
 --------
@@ -15,7 +38,7 @@ Project Status
 
 Basically, everything needed for a working Bitmessage client is there:
 * Creating new identities (private addresses)
-* Adding contracts and subscriptions
+* Adding contacts and subscriptions
 * Receiving broadcasts
 * Receiving messages
 * Sending messages and broadcasts
@@ -27,20 +50,27 @@ Basically, everything needed for a working Bitmessage client is there:
 Setup
 -----
 
+It is recommended to define the version like this:
+```Gradle
+ext.jabitVersion = '2.0.0'
+```
 Add Jabit as Gradle dependency:
 ```Gradle
-compile 'ch.dissem.jabit:jabit-domain:0.2.0'
+compile "ch.dissem.jabit:jabit-core:$jabitVersion"
 ```
 Unless you want to implement your own, also add the following:
 ```Gradle
-compile 'ch.dissem.jabit:jabit-networking:0.2.0'
-compile 'ch.dissem.jabit:jabit-repositories:0.2.0'
+compile "ch.dissem.jabit:jabit-networking:$jabitVersion"
+compile "ch.dissem.jabit:jabit-repositories:$jabitVersion"
+compile "ch.dissem.jabit:jabit-cryptography-bouncy:$jabitVersion"
 ```
 And if you want to import from or export to the Wallet Import Format (used by PyBitmessage) you might also want to add:
 ```Gradle
-compile 'ch.dissem.jabit:jabit-wif:0.2.0'
+compile "ch.dissem.jabit:jabit-wif:$jabitVersion"
 ```
 
+For Android clients use `jabit-cryptography-spongy` instead of `jabit-cryptography-bouncy`.
+
 Usage
 -----
 
@@ -51,19 +81,26 @@ BitmessageContext ctx = new BitmessageContext.Builder()
         .addressRepo(new JdbcAddressRepository(jdbcConfig))
         .inventory(new JdbcInventory(jdbcConfig))
         .messageRepo(new JdbcMessageRepository(jdbcConfig))
-        .nodeRegistry(new MemoryNodeRegistry())
-        .networkHandler(new NetworkNode())
+        .powRepo(new JdbcProofOfWorkRepository(jdbcConfig))
+        .nodeRegistry(new JdbcNodeRegistry(jdbcConfig))
+        .networkHandler(new NioNetworkHandler())
+        .cryptography(new BouncyCryptography())
+        .listener(System.out::println)
         .build();
 ```
-This creates a simple context using a H2 database that will be created in the user's home directory. Next you'll need to
-start the context and decide what happens if a message arrives:
+This creates a simple context using a H2 database that will be created in the user's home directory. In the listener you decide what happens when a message arrives. If you can't use lambdas, you may instead write
 ```Java
-ctx.startup(new BitmessageContext.Listener() {
-    @Override
-    public void receive(Plaintext plaintext) {
-        // TODO: Notify the user
-    }
-});
+        .listener(new BitmessageContext.Listener() {
+            @Override
+            public void receive(Plaintext plaintext) {
+                // TODO: Notify the user
+            }
+        })
+```
+
+Next you'll need to start the context:
+```Java
+ctx.startup()
 ```
 Then you might want to create an identity
 ```Java
@@ -79,3 +116,22 @@ to which you can send some messages
 ```Java
 ctx.send(identity, contact, "Test", "Hello Chris, this is a message.");
 ```
+
+### Housekeeping
+
+As Bitmessage stores all currently valid messages, we'll need to delete expired objects from time to time:
+```Java
+ctx.cleanup();
+```
+If the client runs all the time, it might be a good idea to do this daily or at least weekly. Otherwise, you might just want to clean up on shutdown.
+
+Also, if some messages weren't acknowledged when it expired, they can be resent:
+```Java
+ctx.resendUnacknowledgedMessages();
+```
+This could be triggered periodically, or manually by the user. Please be aware that _if_ there is a message to resend, proof of work needs to be calculated, so to not annoy your users you might not want to trigger it on shutdown. As the client might have been offline for some time, it might as well be wise to wait until it caught up downloading new messages before resending those messages, after all they might be acknowledged by now.
+
+There probably won't happen extremely bad things if you don't - at least not more than otherwise - but you can properly shutdown the network connection by calling
+```Java
+ctx.shutdown();
+```

build.gradle

@@ -2,17 +2,22 @@ subprojects {
     apply plugin: 'java'
     apply plugin: 'maven'
     apply plugin: 'signing'
+    apply plugin: 'jacoco'
+    apply plugin: 'gitflow-version'
 
     sourceCompatibility = 1.7
     group = 'ch.dissem.jabit'
-    version = '0.2.0'
-
-    ext.isReleaseVersion = !version.endsWith("SNAPSHOT")
 
     repositories {
         mavenCentral()
     }
 
+    test {
+        testLogging {
+            exceptionFormat = 'full'
+        }
+    }
+
     task javadocJar(type: Jar) {
         classifier = 'javadoc'
         from javadoc
@@ -28,7 +33,7 @@ subprojects {
     }
 
     signing {
-        required { isReleaseVersion && gradle.taskGraph.hasTask("uploadArchives") }
+        required { isRelease && project.getProperties().get("signing.keyId")?.length() > 0 }
         sign configurations.archives
     }
 
@@ -37,11 +42,6 @@ subprojects {
             mavenDeployer {
                 beforeDeployment { MavenDeployment deployment -> signing.signPom(deployment) }
 
-                if (!hasProperty('ossrhUsername')) {
-                    ext.ossrhUsername = 'dummy'
-                    ext.ossrhPassword = 'dummy'
-                }
-
                 repository(url: "https://oss.sonatype.org/service/local/staging/deploy/maven2/") {
                     authentication(userName: ossrhUsername, password: ossrhPassword)
                 }
@@ -78,4 +78,13 @@ subprojects {
             }
         }
     }
-}
+
+    jacocoTestReport {
+        reports {
+            xml.enabled = true
+            html.enabled = true
+        }
+    }
+
+    check.dependsOn jacocoTestReport
+}

buildSrc/src/main/groovy/ch/dissem/gradle/GitFlowVersion.groovy

@@ -0,0 +1,57 @@
+package ch.dissem.gradle
+
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+
+/**
+ * Sets the version as follows:
+ * <ul>
+ *     <li>If the branch is 'master', the version is set to the latest tag (which is expected to be set by Git flow)</li>
+ *     <li>Otherwise, the version is set to the branch name, with '-SNAPSHOT' appended</li>
+ * </ul>
+ */
+class GitFlowVersion implements Plugin<Project> {
+    def getBranch(Project project) {
+        def stdout = new ByteArrayOutputStream()
+        project.exec {
+            commandLine 'git', 'rev-parse', '--abbrev-ref', 'HEAD'
+            standardOutput = stdout
+        }
+        return stdout.toString().trim()
+    }
+
+    def getTag(Project project) {
+        def stdout = new ByteArrayOutputStream()
+        project.exec {
+            commandLine 'git', 'describe', '--abbrev=0'
+            standardOutput = stdout
+        }
+        return stdout.toString().trim()
+    }
+
+    def isRelease(Project project) {
+        return "master" == getBranch(project);
+    }
+
+    def getVersion(Project project) {
+        if (project.ext.isRelease) {
+            return getTag(project)
+        } else {
+            def branch = getBranch(project)
+            if ("develop" == branch) {
+                return "development-SNAPSHOT"
+            }
+            return branch.replaceAll("/", "-") + "-SNAPSHOT"
+        }
+    }
+
+    @Override
+    void apply(Project project) {
+        project.ext.isRelease = isRelease(project)
+        project.version = getVersion(project)
+
+        project.task('version') << {
+            println "Version deduced from git: '${project.version}'"
+        }
+    }
+}

buildSrc/src/main/resources/META-INF/gradle-plugins/gitflow-version.properties

@@ -0,0 +1 @@
+implementation-class=ch.dissem.gradle.GitFlowVersion

core/build.gradle

@@ -0,0 +1,32 @@
+uploadArchives {
+    repositories {
+        mavenDeployer {
+            pom.project {
+                name 'Jabit Core'
+                artifactId = 'jabit-core'
+                description 'A Java implementation of the Bitmessage protocol. This is the core part. You\'ll either need the networking and repositories modules, too, or implement your own.'
+            }
+        }
+    }
+}
+
+configurations {
+    testArtifacts.extendsFrom testRuntime
+}
+
+task testJar(type: Jar) {
+    classifier = 'test'
+    from sourceSets.test.output
+}
+
+artifacts {
+    testArtifacts testJar
+}
+
+dependencies {
+    compile 'org.slf4j:slf4j-api:1.7.12'
+    testCompile 'junit:junit:4.12'
+    testCompile 'org.hamcrest:hamcrest-library:1.3'
+    testCompile 'org.mockito:mockito-core:1.10.19'
+    testCompile project(':cryptography-bc')
+}

core/src/main/java/ch/dissem/bitmessage/BitmessageContext.java

@@ -0,0 +1,451 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage;
+
+import ch.dissem.bitmessage.entity.*;
+import ch.dissem.bitmessage.entity.payload.Broadcast;
+import ch.dissem.bitmessage.entity.payload.ObjectType;
+import ch.dissem.bitmessage.entity.payload.Pubkey.Feature;
+import ch.dissem.bitmessage.entity.valueobject.PrivateKey;
+import ch.dissem.bitmessage.exception.DecryptionFailedException;
+import ch.dissem.bitmessage.factory.Factory;
+import ch.dissem.bitmessage.ports.*;
+import ch.dissem.bitmessage.utils.Property;
+import ch.dissem.bitmessage.utils.TTL;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.net.InetAddress;
+import java.util.List;
+import java.util.concurrent.CancellationException;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+
+import static ch.dissem.bitmessage.InternalContext.NETWORK_EXTRA_BYTES;
+import static ch.dissem.bitmessage.InternalContext.NETWORK_NONCE_TRIALS_PER_BYTE;
+import static ch.dissem.bitmessage.entity.Plaintext.Type.BROADCAST;
+import static ch.dissem.bitmessage.entity.Plaintext.Type.MSG;
+import static ch.dissem.bitmessage.utils.UnixTime.*;
+
+/**
+ * <p>Use this class if you want to create a Bitmessage client.</p>
+ * You'll need the Builder to create a BitmessageContext, and set the following properties:
+ * <ul>
+ * <li>addressRepo</li>
+ * <li>inventory</li>
+ * <li>nodeRegistry</li>
+ * <li>networkHandler</li>
+ * <li>messageRepo</li>
+ * <li>streams</li>
+ * </ul>
+ * <p>The default implementations in the different module builds can be used.</p>
+ * <p>The port defaults to 8444 (the default Bitmessage port)</p>
+ */
+public class BitmessageContext {
+    public static final int CURRENT_VERSION = 3;
+    private final static Logger LOG = LoggerFactory.getLogger(BitmessageContext.class);
+
+    private final InternalContext ctx;
+
+    private final Labeler labeler;
+
+    private final boolean sendPubkeyOnIdentityCreation;
+
+    private BitmessageContext(Builder builder) {
+        if (builder.listener instanceof Listener.WithContext) {
+            ((Listener.WithContext) builder.listener).setContext(this);
+        }
+        ctx = new InternalContext(builder);
+        labeler = builder.labeler;
+        ctx.getProofOfWorkService().doMissingProofOfWork(30_000); // TODO: this should be configurable
+        sendPubkeyOnIdentityCreation = builder.sendPubkeyOnIdentityCreation;
+    }
+
+    public AddressRepository addresses() {
+        return ctx.getAddressRepository();
+    }
+
+    public MessageRepository messages() {
+        return ctx.getMessageRepository();
+    }
+
+    public Labeler labeler() {
+        return labeler;
+    }
+
+    public BitmessageAddress createIdentity(boolean shorter, Feature... features) {
+        final BitmessageAddress identity = new BitmessageAddress(new PrivateKey(
+            shorter,
+            ctx.getStreams()[0],
+            NETWORK_NONCE_TRIALS_PER_BYTE,
+            NETWORK_EXTRA_BYTES,
+            features
+        ));
+        ctx.getAddressRepository().save(identity);
+        if (sendPubkeyOnIdentityCreation) {
+            ctx.sendPubkey(identity, identity.getStream());
+        }
+        return identity;
+    }
+
+    public BitmessageAddress joinChan(String passphrase, String address) {
+        BitmessageAddress chan = BitmessageAddress.chan(address, passphrase);
+        chan.setAlias(passphrase);
+        ctx.getAddressRepository().save(chan);
+        return chan;
+    }
+
+    public BitmessageAddress createChan(String passphrase) {
+        // FIXME: hardcoded stream number
+        BitmessageAddress chan = BitmessageAddress.chan(1, passphrase);
+        ctx.getAddressRepository().save(chan);
+        return chan;
+    }
+
+    public List<BitmessageAddress> createDeterministicAddresses(
+        String passphrase, int numberOfAddresses, long version, long stream, boolean shorter) {
+        List<BitmessageAddress> result = BitmessageAddress.deterministic(
+            passphrase, numberOfAddresses, version, stream, shorter);
+        for (int i = 0; i < result.size(); i++) {
+            BitmessageAddress address = result.get(i);
+            address.setAlias("deterministic (" + (i + 1) + ")");
+            ctx.getAddressRepository().save(address);
+        }
+        return result;
+    }
+
+    public void broadcast(final BitmessageAddress from, final String subject, final String message) {
+        Plaintext msg = new Plaintext.Builder(BROADCAST)
+            .from(from)
+            .message(subject, message)
+            .build();
+        send(msg);
+    }
+
+    public void send(final BitmessageAddress from, final BitmessageAddress to, final String subject, final String message) {
+        if (from.getPrivateKey() == null) {
+            throw new IllegalArgumentException("'From' must be an identity, i.e. have a private key.");
+        }
+        Plaintext msg = new Plaintext.Builder(MSG)
+            .from(from)
+            .to(to)
+            .message(subject, message)
+            .build();
+        send(msg);
+    }
+
+    public void send(final Plaintext msg) {
+        if (msg.getFrom() == null || msg.getFrom().getPrivateKey() == null) {
+            throw new IllegalArgumentException("'From' must be an identity, i.e. have a private key.");
+        }
+        labeler().markAsSending(msg);
+        BitmessageAddress to = msg.getTo();
+        if (to != null) {
+            if (to.getPubkey() == null) {
+                LOG.info("Public key is missing from recipient. Requesting.");
+                ctx.requestPubkey(to);
+            }
+            if (to.getPubkey() == null) {
+                ctx.getMessageRepository().save(msg);
+            }
+        }
+        if (to == null || to.getPubkey() != null) {
+            LOG.info("Sending message.");
+            ctx.getMessageRepository().save(msg);
+            if (msg.getType() == MSG) {
+                ctx.send(msg);
+            } else {
+                ctx.send(
+                    msg.getFrom(),
+                    to,
+                    Factory.getBroadcast(msg),
+                    msg.getTTL()
+                );
+            }
+        }
+    }
+
+    public void startup() {
+        ctx.getNetworkHandler().start();
+    }
+
+    public void shutdown() {
+        ctx.getNetworkHandler().stop();
+    }
+
+    /**
+     * @param host             a trusted node that must be reliable (it's used for every synchronization)
+     * @param port             of the trusted host, default is 8444
+     * @param timeoutInSeconds synchronization should end no later than about 5 seconds after the timeout elapsed, even
+     *                         if not all objects were fetched
+     * @param wait             waits for the synchronization thread to finish
+     */
+    public void synchronize(InetAddress host, int port, long timeoutInSeconds, boolean wait) {
+        Future<?> future = ctx.getNetworkHandler().synchronize(host, port, timeoutInSeconds);
+        if (wait) {
+            try {
+                future.get();
+            } catch (InterruptedException e) {
+                LOG.info("Thread was interrupted. Trying to shut down synchronization and returning.");
+                future.cancel(true);
+            } catch (CancellationException | ExecutionException e) {
+                LOG.debug(e.getMessage(), e);
+            }
+        }
+    }
+
+    /**
+     * Send a custom message to a specific node (that should implement handling for this message type) and returns
+     * the response, which in turn is expected to be a {@link CustomMessage}.
+     *
+     * @param server  the node's address
+     * @param port    the node's port
+     * @param request the request
+     * @return the response
+     */
+    public CustomMessage send(InetAddress server, int port, CustomMessage request) {
+        return ctx.getNetworkHandler().send(server, port, request);
+    }
+
+    /**
+     * Removes expired objects from the inventory. You should call this method regularly,
+     * e.g. daily and on each shutdown.
+     */
+    public void cleanup() {
+        ctx.getInventory().cleanup();
+    }
+
+    /**
+     * Sends messages again whose time to live expired without being acknowledged. (And whose
+     * recipient is expected to send acknowledgements.
+     * <p>
+     * You should call this method regularly, but be aware of the following:
+     * <ul>
+     * <li>As messages might be sent, POW will be done. It is therefore not advised to
+     * call it on shutdown.</li>
+     * <li>It shouldn't be called right after startup, as it's possible the missing
+     * acknowledgement was sent while the client was offline.</li>
+     * <li>Other than that, the call isn't expensive as long as there is no message
+     * to send, so it might be a good idea to just call it every few minutes.</li>
+     * </ul>
+     */
+    public void resendUnacknowledgedMessages() {
+        ctx.resendUnacknowledged();
+    }
+
+    public boolean isRunning() {
+        return ctx.getNetworkHandler().isRunning();
+    }
+
+    public void addContact(BitmessageAddress contact) {
+        ctx.getAddressRepository().save(contact);
+        if (contact.getPubkey() == null) {
+            ctx.requestPubkey(contact);
+        }
+    }
+
+    public void addSubscribtion(BitmessageAddress address) {
+        address.setSubscribed(true);
+        ctx.getAddressRepository().save(address);
+        tryToFindBroadcastsForAddress(address);
+    }
+
+    private void tryToFindBroadcastsForAddress(BitmessageAddress address) {
+        for (ObjectMessage object : ctx.getInventory().getObjects(address.getStream(), Broadcast.getVersion(address), ObjectType.BROADCAST)) {
+            try {
+                Broadcast broadcast = (Broadcast) object.getPayload();
+                broadcast.decrypt(address);
+                // This decrypts it twice, but on the other hand it doesn't try to decrypt the objects with
+                // other subscriptions and the interface stays as simple as possible.
+                ctx.getNetworkListener().receive(object);
+            } catch (DecryptionFailedException ignore) {
+            } catch (Exception e) {
+                LOG.debug(e.getMessage(), e);
+            }
+        }
+    }
+
+    public Property status() {
+        return new Property("status", null,
+            ctx.getNetworkHandler().getNetworkStatus(),
+            new Property("unacknowledged", ctx.getMessageRepository().findMessagesToResend().size())
+        );
+    }
+
+    /**
+     * Returns the {@link InternalContext} - normally you wouldn't need it,
+     * unless you are doing something crazy with the protocol.
+     */
+    public InternalContext internals() {
+        return ctx;
+    }
+
+    public interface Listener {
+        void receive(Plaintext plaintext);
+
+        /**
+         * A message listener that needs a {@link BitmessageContext}, i.e. for implementing some sort of chat bot.
+         */
+        interface WithContext extends Listener {
+            void setContext(BitmessageContext ctx);
+        }
+    }
+
+    public static final class Builder {
+        int port = 8444;
+        Inventory inventory;
+        NodeRegistry nodeRegistry;
+        NetworkHandler networkHandler;
+        AddressRepository addressRepo;
+        MessageRepository messageRepo;
+        ProofOfWorkRepository proofOfWorkRepository;
+        ProofOfWorkEngine proofOfWorkEngine;
+        Cryptography cryptography;
+        CustomCommandHandler customCommandHandler;
+        Labeler labeler;
+        Listener listener;
+        int connectionLimit = 150;
+        long connectionTTL = 30 * MINUTE;
+        boolean sendPubkeyOnIdentityCreation = true;
+
+        public Builder port(int port) {
+            this.port = port;
+            return this;
+        }
+
+        public Builder inventory(Inventory inventory) {
+            this.inventory = inventory;
+            return this;
+        }
+
+        public Builder nodeRegistry(NodeRegistry nodeRegistry) {
+            this.nodeRegistry = nodeRegistry;
+            return this;
+        }
+
+        public Builder networkHandler(NetworkHandler networkHandler) {
+            this.networkHandler = networkHandler;
+            return this;
+        }
+
+        public Builder addressRepo(AddressRepository addressRepo) {
+            this.addressRepo = addressRepo;
+            return this;
+        }
+
+        public Builder messageRepo(MessageRepository messageRepo) {
+            this.messageRepo = messageRepo;
+            return this;
+        }
+
+        public Builder powRepo(ProofOfWorkRepository proofOfWorkRepository) {
+            this.proofOfWorkRepository = proofOfWorkRepository;
+            return this;
+        }
+
+        public Builder cryptography(Cryptography cryptography) {
+            this.cryptography = cryptography;
+            return this;
+        }
+
+        public Builder customCommandHandler(CustomCommandHandler handler) {
+            this.customCommandHandler = handler;
+            return this;
+        }
+
+        public Builder proofOfWorkEngine(ProofOfWorkEngine proofOfWorkEngine) {
+            this.proofOfWorkEngine = proofOfWorkEngine;
+            return this;
+        }
+
+        public Builder labeler(Labeler labeler) {
+            this.labeler = labeler;
+            return this;
+        }
+
+        public Builder listener(Listener listener) {
+            this.listener = listener;
+            return this;
+        }
+
+        public Builder connectionLimit(int connectionLimit) {
+            this.connectionLimit = connectionLimit;
+            return this;
+        }
+
+        public Builder connectionTTL(int hours) {
+            this.connectionTTL = hours * HOUR;
+            return this;
+        }
+
+        /**
+         * By default a client will send the public key when an identity is being created. On weaker devices
+         * this behaviour might not be desirable.
+         */
+        public Builder doNotSendPubkeyOnIdentityCreation() {
+            this.sendPubkeyOnIdentityCreation = false;
+            return this;
+        }
+
+        /**
+         * Time to live in seconds for public keys the client sends. Defaults to the maximum of 28 days,
+         * but on weak devices smaller values might be desirable.
+         * <p>
+         * Please be aware that this might cause some problems where you can't receive a message (the
+         * sender can't receive your public key) in some special situations. Also note that it's probably
+         * not a good idea to set it too low.
+         * </p>
+         *
+         * @deprecated use {@link TTL#pubkey(long)} instead.
+         */
+        public Builder pubkeyTTL(long days) {
+            if (days < 0 || days > 28 * DAY) throw new IllegalArgumentException("TTL must be between 1 and 28 days");
+            TTL.pubkey(days);
+            return this;
+        }
+
+        public BitmessageContext build() {
+            nonNull("inventory", inventory);
+            nonNull("nodeRegistry", nodeRegistry);
+            nonNull("networkHandler", networkHandler);
+            nonNull("addressRepo", addressRepo);
+            nonNull("messageRepo", messageRepo);
+            nonNull("proofOfWorkRepo", proofOfWorkRepository);
+            if (proofOfWorkEngine == null) {
+                proofOfWorkEngine = new MultiThreadedPOWEngine();
+            }
+            if (labeler == null) {
+                labeler = new DefaultLabeler();
+            }
+            if (customCommandHandler == null) {
+                customCommandHandler = new CustomCommandHandler() {
+                    @Override
+                    public MessagePayload handle(CustomMessage request) {
+                        throw new IllegalStateException(
+                            "Received custom request, but no custom command handler configured.");
+                    }
+                };
+            }
+            return new BitmessageContext(this);
+        }
+
+        private void nonNull(String name, Object o) {
+            if (o == null) throw new IllegalStateException(name + " must not be null");
+        }
+    }
+
+}

core/src/main/java/ch/dissem/bitmessage/DefaultMessageListener.java

@@ -20,8 +20,9 @@ import ch.dissem.bitmessage.entity.BitmessageAddress;
 import ch.dissem.bitmessage.entity.ObjectMessage;
 import ch.dissem.bitmessage.entity.Plaintext;
 import ch.dissem.bitmessage.entity.payload.*;
-import ch.dissem.bitmessage.entity.valueobject.Label;
+import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
 import ch.dissem.bitmessage.exception.DecryptionFailedException;
+import ch.dissem.bitmessage.ports.Labeler;
 import ch.dissem.bitmessage.ports.NetworkHandler;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -30,23 +31,34 @@ import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
-import static ch.dissem.bitmessage.entity.Plaintext.Status.*;
-import static ch.dissem.bitmessage.utils.UnixTime.DAY;
+import static ch.dissem.bitmessage.entity.Plaintext.Status.PUBKEY_REQUESTED;
 
-class DefaultMessageListener implements NetworkHandler.MessageListener {
+class DefaultMessageListener implements NetworkHandler.MessageListener, InternalContext.ContextHolder {
     private final static Logger LOG = LoggerFactory.getLogger(DefaultMessageListener.class);
-    private final InternalContext ctx;
+    private final Labeler labeler;
     private final BitmessageContext.Listener listener;
+    private InternalContext ctx;
 
-    public DefaultMessageListener(InternalContext context, BitmessageContext.Listener listener) {
-        this.ctx = context;
+    public DefaultMessageListener(Labeler labeler, BitmessageContext.Listener listener) {
+        this.labeler = labeler;
         this.listener = listener;
     }
 
     @Override
+    public void setContext(InternalContext context) {
+        this.ctx = context;
+    }
+
+    @Override
+    @SuppressWarnings("ConstantConditions")
     public void receive(ObjectMessage object) throws IOException {
         ObjectPayload payload = object.getPayload();
-        if (payload.getType() == null) return;
+        if (payload.getType() == null) {
+            if (payload instanceof GenericPayload) {
+                receive((GenericPayload) payload);
+            }
+            return;
+        }
 
         switch (payload.getType()) {
             case GET_PUBKEY: {
@@ -65,13 +77,17 @@ class DefaultMessageListener implements NetworkHandler.MessageListener {
                 receive(object, (Broadcast) payload);
                 break;
             }
+            default: {
+                throw new IllegalArgumentException("Unknown payload type " + payload.getType());
+            }
         }
     }
 
     protected void receive(ObjectMessage object, GetPubkey getPubkey) {
-        BitmessageAddress identity = ctx.getAddressRepo().findIdentity(getPubkey.getRipeTag());
-        if (identity != null && identity.getPrivateKey() != null) {
-            LOG.debug("Got pubkey request for identity " + identity);
+        BitmessageAddress identity = ctx.getAddressRepository().findIdentity(getPubkey.getRipeTag());
+        if (identity != null && identity.getPrivateKey() != null && !identity.isChan()) {
+            LOG.info("Got pubkey request for identity " + identity);
+            // FIXME: only send pubkey if it wasn't sent in the last 28 days
             ctx.sendPubkey(identity, object.getStream());
         }
     }
@@ -81,51 +97,43 @@ class DefaultMessageListener implements NetworkHandler.MessageListener {
         try {
             if (pubkey instanceof V4Pubkey) {
                 V4Pubkey v4Pubkey = (V4Pubkey) pubkey;
-                address = ctx.getAddressRepo().findContact(v4Pubkey.getTag());
+                address = ctx.getAddressRepository().findContact(v4Pubkey.getTag());
                 if (address != null) {
                     v4Pubkey.decrypt(address.getPublicDecryptionKey());
                 }
             } else {
-                address = ctx.getAddressRepo().findContact(pubkey.getRipe());
+                address = ctx.getAddressRepository().findContact(pubkey.getRipe());
             }
             if (address != null) {
-                address.setPubkey(pubkey);
-                LOG.debug("Got pubkey for contact " + address);
-                ctx.getAddressRepo().save(address);
-                List<Plaintext> messages = ctx.getMessageRepository().findMessages(Plaintext.Status.PUBKEY_REQUESTED, address);
-                LOG.debug("Sending " + messages.size() + " messages for contact " + address);
-                for (Plaintext msg : messages) {
-                    msg.setStatus(DOING_PROOF_OF_WORK);
-                    ctx.getMessageRepository().save(msg);
-                    ctx.send(
-                            msg.getFrom(),
-                            msg.getTo(),
-                            new Msg(msg),
-                            +2 * DAY,
-                            ctx.getNonceTrialsPerByte(msg.getTo()),
-                            ctx.getExtraBytes(msg.getTo())
-                    );
-                    msg.setStatus(SENT);
-                    ctx.getMessageRepository().save(msg);
-                }
+                updatePubkey(address, pubkey);
             }
         } catch (DecryptionFailedException ignore) {
         }
     }
 
+    private void updatePubkey(BitmessageAddress address, Pubkey pubkey) {
+        address.setPubkey(pubkey);
+        LOG.info("Got pubkey for contact " + address);
+        ctx.getAddressRepository().save(address);
+        List<Plaintext> messages = ctx.getMessageRepository().findMessages(PUBKEY_REQUESTED, address);
+        LOG.info("Sending " + messages.size() + " messages for contact " + address);
+        for (Plaintext msg : messages) {
+            ctx.getLabeler().markAsSending(msg);
+            ctx.getMessageRepository().save(msg);
+            ctx.send(msg);
+        }
+    }
+
     protected void receive(ObjectMessage object, Msg msg) throws IOException {
-        for (BitmessageAddress identity : ctx.getAddressRepo().getIdentities()) {
+        for (BitmessageAddress identity : ctx.getAddressRepository().getIdentities()) {
             try {
                 msg.decrypt(identity.getPrivateKey().getPrivateEncryptionKey());
-                msg.getPlaintext().setTo(identity);
-                if (!object.isSignatureValid(msg.getPlaintext().getFrom().getPubkey())) {
+                Plaintext plaintext = msg.getPlaintext();
+                plaintext.setTo(identity);
+                if (!object.isSignatureValid(plaintext.getFrom().getPubkey())) {
                     LOG.warn("Msg with IV " + object.getInventoryVector() + " was successfully decrypted, but signature check failed. Ignoring.");
                 } else {
-                    msg.getPlaintext().setStatus(RECEIVED);
-                    msg.getPlaintext().addLabels(ctx.getMessageRepository().getLabels(Label.Type.INBOX, Label.Type.UNREAD));
-                    msg.getPlaintext().setInventoryVector(object.getInventoryVector());
-                    ctx.getMessageRepository().save(msg.getPlaintext());
-                    listener.receive(msg.getPlaintext());
+                    receive(object.getInventoryVector(), plaintext);
                 }
                 break;
             } catch (DecryptionFailedException ignore) {
@@ -133,9 +141,19 @@ class DefaultMessageListener implements NetworkHandler.MessageListener {
         }
     }
 
+    protected void receive(GenericPayload ack) {
+        if (ack.getData().length == Msg.ACK_LENGTH) {
+            Plaintext msg = ctx.getMessageRepository().getMessageForAck(ack.getData());
+            if (msg != null) {
+                ctx.getLabeler().markAsAcknowledged(msg);
+                ctx.getMessageRepository().save(msg);
+            }
+        }
+    }
+
     protected void receive(ObjectMessage object, Broadcast broadcast) throws IOException {
         byte[] tag = broadcast instanceof V5Broadcast ? ((V5Broadcast) broadcast).getTag() : null;
-        for (BitmessageAddress subscription : ctx.getAddressRepo().getSubscriptions(broadcast.getVersion())) {
+        for (BitmessageAddress subscription : ctx.getAddressRepository().getSubscriptions(broadcast.getVersion())) {
             if (tag != null && !Arrays.equals(tag, subscription.getTag())) {
                 continue;
             }
@@ -144,14 +162,26 @@ class DefaultMessageListener implements NetworkHandler.MessageListener {
                 if (!object.isSignatureValid(broadcast.getPlaintext().getFrom().getPubkey())) {
                     LOG.warn("Broadcast with IV " + object.getInventoryVector() + " was successfully decrypted, but signature check failed. Ignoring.");
                 } else {
-                    broadcast.getPlaintext().setStatus(RECEIVED);
-                    broadcast.getPlaintext().addLabels(ctx.getMessageRepository().getLabels(Label.Type.INBOX, Label.Type.BROADCAST, Label.Type.UNREAD));
-                    broadcast.getPlaintext().setInventoryVector(object.getInventoryVector());
-                    ctx.getMessageRepository().save(broadcast.getPlaintext());
-                    listener.receive(broadcast.getPlaintext());
+                    receive(object.getInventoryVector(), broadcast.getPlaintext());
                 }
             } catch (DecryptionFailedException ignore) {
             }
         }
     }
+
+    protected void receive(InventoryVector iv, Plaintext msg) {
+        msg.setInventoryVector(iv);
+        labeler.setLabels(msg);
+        ctx.getMessageRepository().save(msg);
+        listener.receive(msg);
+        updatePubkey(msg.getFrom(), msg.getFrom().getPubkey());
+
+        if (msg.getType() == Plaintext.Type.MSG && msg.getTo().has(Pubkey.Feature.DOES_ACK)) {
+            ObjectMessage ack = msg.getAckMessage();
+            if (ack != null) {
+                ctx.getInventory().storeObject(ack);
+                ctx.getNetworkHandler().offer(ack.getInventoryVector());
+            }
+        }
+    }
 }

core/src/main/java/ch/dissem/bitmessage/InternalContext.java

@@ -0,0 +1,317 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage;
+
+import ch.dissem.bitmessage.entity.*;
+import ch.dissem.bitmessage.entity.payload.*;
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.ports.*;
+import ch.dissem.bitmessage.utils.Singleton;
+import ch.dissem.bitmessage.utils.TTL;
+import ch.dissem.bitmessage.utils.UnixTime;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.TreeSet;
+
+/**
+ * The internal context should normally only be used for port implementations. If you need it in your client
+ * implementation, you're either doing something wrong, something very weird, or the BitmessageContext should
+ * get extended.
+ * <p>
+ * On the other hand, if you need the BitmessageContext in a port implementation, the same thing might apply.
+ * </p>
+ */
+public class InternalContext {
+    private final static Logger LOG = LoggerFactory.getLogger(InternalContext.class);
+
+    public final static long NETWORK_NONCE_TRIALS_PER_BYTE = 1000;
+    public final static long NETWORK_EXTRA_BYTES = 1000;
+
+    private final Cryptography cryptography;
+    private final Inventory inventory;
+    private final NodeRegistry nodeRegistry;
+    private final NetworkHandler networkHandler;
+    private final AddressRepository addressRepository;
+    private final MessageRepository messageRepository;
+    private final ProofOfWorkRepository proofOfWorkRepository;
+    private final ProofOfWorkEngine proofOfWorkEngine;
+    private final CustomCommandHandler customCommandHandler;
+    private final ProofOfWorkService proofOfWorkService;
+    private final Labeler labeler;
+    private final NetworkHandler.MessageListener networkListener;
+
+    private final TreeSet<Long> streams = new TreeSet<>();
+    private final int port;
+    private final long clientNonce;
+    private long connectionTTL;
+    private int connectionLimit;
+
+    public InternalContext(BitmessageContext.Builder builder) {
+        this.cryptography = builder.cryptography;
+        this.inventory = builder.inventory;
+        this.nodeRegistry = builder.nodeRegistry;
+        this.networkHandler = builder.networkHandler;
+        this.addressRepository = builder.addressRepo;
+        this.messageRepository = builder.messageRepo;
+        this.proofOfWorkRepository = builder.proofOfWorkRepository;
+        this.proofOfWorkService = new ProofOfWorkService();
+        this.proofOfWorkEngine = builder.proofOfWorkEngine;
+        this.clientNonce = cryptography.randomNonce();
+        this.customCommandHandler = builder.customCommandHandler;
+        this.port = builder.port;
+        this.connectionLimit = builder.connectionLimit;
+        this.connectionTTL = builder.connectionTTL;
+        this.labeler = builder.labeler;
+        this.networkListener = new DefaultMessageListener(labeler, builder.listener);
+
+        Singleton.initialize(cryptography);
+
+        // TODO: streams of new identities and subscriptions should also be added. This works only after a restart.
+        for (BitmessageAddress address : addressRepository.getIdentities()) {
+            streams.add(address.getStream());
+        }
+        for (BitmessageAddress address : addressRepository.getSubscriptions()) {
+            streams.add(address.getStream());
+        }
+        if (streams.isEmpty()) {
+            streams.add(1L);
+        }
+
+        init(cryptography, inventory, nodeRegistry, networkHandler, addressRepository, messageRepository,
+            proofOfWorkRepository, proofOfWorkService, proofOfWorkEngine, customCommandHandler, builder.labeler,
+            networkListener);
+        for (BitmessageAddress identity : addressRepository.getIdentities()) {
+            streams.add(identity.getStream());
+        }
+    }
+
+    private void init(Object... objects) {
+        for (Object o : objects) {
+            if (o instanceof ContextHolder) {
+                ((ContextHolder) o).setContext(this);
+            }
+        }
+    }
+
+    public Cryptography getCryptography() {
+        return cryptography;
+    }
+
+    public Inventory getInventory() {
+        return inventory;
+    }
+
+    public NodeRegistry getNodeRegistry() {
+        return nodeRegistry;
+    }
+
+    public NetworkHandler getNetworkHandler() {
+        return networkHandler;
+    }
+
+    public AddressRepository getAddressRepository() {
+        return addressRepository;
+    }
+
+    public MessageRepository getMessageRepository() {
+        return messageRepository;
+    }
+
+    public ProofOfWorkRepository getProofOfWorkRepository() {
+        return proofOfWorkRepository;
+    }
+
+    public ProofOfWorkEngine getProofOfWorkEngine() {
+        return proofOfWorkEngine;
+    }
+
+    public ProofOfWorkService getProofOfWorkService() {
+        return proofOfWorkService;
+    }
+
+    public Labeler getLabeler() {
+        return labeler;
+    }
+
+    public NetworkHandler.MessageListener getNetworkListener() {
+        return networkListener;
+    }
+
+    public long[] getStreams() {
+        long[] result = new long[streams.size()];
+        int i = 0;
+        for (long stream : streams) {
+            result[i++] = stream;
+        }
+        return result;
+    }
+
+    public int getPort() {
+        return port;
+    }
+
+    public void send(final Plaintext plaintext) {
+        if (plaintext.getAckMessage() != null) {
+            long expires = UnixTime.now(+plaintext.getTTL());
+            LOG.info("Expires at " + expires);
+            proofOfWorkService.doProofOfWorkWithAck(plaintext, expires);
+        } else {
+            send(plaintext.getFrom(), plaintext.getTo(), new Msg(plaintext), plaintext.getTTL());
+        }
+    }
+
+    public void send(final BitmessageAddress from, BitmessageAddress to, final ObjectPayload payload,
+                     final long timeToLive) {
+        try {
+            final BitmessageAddress recipient = (to != null ? to : from);
+            long expires = UnixTime.now(+timeToLive);
+            LOG.info("Expires at " + expires);
+            final ObjectMessage object = new ObjectMessage.Builder()
+                .stream(recipient.getStream())
+                .expiresTime(expires)
+                .payload(payload)
+                .build();
+            if (object.isSigned()) {
+                object.sign(from.getPrivateKey());
+            }
+            if (payload instanceof Broadcast) {
+                ((Broadcast) payload).encrypt();
+            } else if (payload instanceof Encrypted) {
+                object.encrypt(recipient.getPubkey());
+            }
+            proofOfWorkService.doProofOfWork(to, object);
+        } catch (IOException e) {
+            throw new ApplicationException(e);
+        }
+    }
+
+    public void sendPubkey(final BitmessageAddress identity, final long targetStream) {
+        try {
+            long expires = UnixTime.now(TTL.pubkey());
+            LOG.info("Expires at " + expires);
+            final ObjectMessage response = new ObjectMessage.Builder()
+                .stream(targetStream)
+                .expiresTime(expires)
+                .payload(identity.getPubkey())
+                .build();
+            response.sign(identity.getPrivateKey());
+            response.encrypt(cryptography.createPublicKey(identity.getPublicDecryptionKey()));
+            // TODO: remember that the pubkey is just about to be sent, and on which stream!
+            proofOfWorkService.doProofOfWork(response);
+        } catch (IOException e) {
+            throw new ApplicationException(e);
+        }
+    }
+
+    /**
+     * Be aware that if the pubkey already exists in the inventory, the metods will not request it and the callback
+     * for freshly received pubkeys will not be called. Instead the pubkey is added to the contact and stored on DB.
+     */
+    public void requestPubkey(final BitmessageAddress contact) {
+        BitmessageAddress stored = addressRepository.getAddress(contact.getAddress());
+
+        tryToFindMatchingPubkey(contact);
+        if (contact.getPubkey() != null) {
+            if (stored != null) {
+                stored.setPubkey(contact.getPubkey());
+                addressRepository.save(stored);
+            } else {
+                addressRepository.save(contact);
+            }
+            return;
+        }
+
+        if (stored == null) {
+            addressRepository.save(contact);
+        }
+
+        long expires = UnixTime.now(TTL.getpubkey());
+        LOG.info("Expires at " + expires);
+        final ObjectMessage request = new ObjectMessage.Builder()
+            .stream(contact.getStream())
+            .expiresTime(expires)
+            .payload(new GetPubkey(contact))
+            .build();
+        proofOfWorkService.doProofOfWork(request);
+    }
+
+    private void tryToFindMatchingPubkey(BitmessageAddress address) {
+        BitmessageAddress stored = addressRepository.getAddress(address.getAddress());
+        if (stored != null) {
+            address.setAlias(stored.getAlias());
+            address.setSubscribed(stored.isSubscribed());
+        }
+        for (ObjectMessage object : inventory.getObjects(address.getStream(), address.getVersion(), ObjectType.PUBKEY)) {
+            try {
+                Pubkey pubkey = (Pubkey) object.getPayload();
+                if (address.getVersion() == 4) {
+                    V4Pubkey v4Pubkey = (V4Pubkey) pubkey;
+                    if (Arrays.equals(address.getTag(), v4Pubkey.getTag())) {
+                        v4Pubkey.decrypt(address.getPublicDecryptionKey());
+                        if (object.isSignatureValid(v4Pubkey)) {
+                            address.setPubkey(v4Pubkey);
+                            addressRepository.save(address);
+                            break;
+                        } else {
+                            LOG.info("Found pubkey for " + address + " but signature is invalid");
+                        }
+                    }
+                } else {
+                    if (Arrays.equals(pubkey.getRipe(), address.getRipe())) {
+                        address.setPubkey(pubkey);
+                        addressRepository.save(address);
+                        break;
+                    }
+                }
+            } catch (Exception e) {
+                LOG.debug(e.getMessage(), e);
+            }
+        }
+    }
+
+    public void resendUnacknowledged() {
+        List<Plaintext> messages = messageRepository.findMessagesToResend();
+        for (Plaintext message : messages) {
+            send(message);
+            messageRepository.save(message);
+        }
+    }
+
+    public long getClientNonce() {
+        return clientNonce;
+    }
+
+    public long getConnectionTTL() {
+        return connectionTTL;
+    }
+
+    public int getConnectionLimit() {
+        return connectionLimit;
+    }
+
+    public CustomCommandHandler getCustomCommandHandler() {
+        return customCommandHandler;
+    }
+
+    public interface ContextHolder {
+        void setContext(InternalContext context);
+    }
+}

core/src/main/java/ch/dissem/bitmessage/ProofOfWorkService.java

@@ -0,0 +1,125 @@
+package ch.dissem.bitmessage;
+
+import ch.dissem.bitmessage.entity.*;
+import ch.dissem.bitmessage.entity.payload.Msg;
+import ch.dissem.bitmessage.entity.payload.Pubkey;
+import ch.dissem.bitmessage.ports.Cryptography;
+import ch.dissem.bitmessage.ports.MessageRepository;
+import ch.dissem.bitmessage.ports.ProofOfWorkEngine;
+import ch.dissem.bitmessage.ports.ProofOfWorkRepository;
+import ch.dissem.bitmessage.ports.ProofOfWorkRepository.Item;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Timer;
+import java.util.TimerTask;
+
+import static ch.dissem.bitmessage.InternalContext.NETWORK_EXTRA_BYTES;
+import static ch.dissem.bitmessage.InternalContext.NETWORK_NONCE_TRIALS_PER_BYTE;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
+
+/**
+ * @author Christian Basler
+ */
+public class ProofOfWorkService implements ProofOfWorkEngine.Callback, InternalContext.ContextHolder {
+    private final static Logger LOG = LoggerFactory.getLogger(ProofOfWorkService.class);
+
+    private Cryptography cryptography;
+    private InternalContext ctx;
+    private ProofOfWorkRepository powRepo;
+    private MessageRepository messageRepo;
+
+    public void doMissingProofOfWork(long delayInMilliseconds) {
+        final List<byte[]> items = powRepo.getItems();
+        if (items.isEmpty()) return;
+
+        // Wait for 30 seconds, to let the application start up before putting heavy load on the CPU
+        new Timer().schedule(new TimerTask() {
+            @Override
+            public void run() {
+                LOG.info("Doing POW for " + items.size() + " tasks.");
+                for (byte[] initialHash : items) {
+                    Item item = powRepo.getItem(initialHash);
+                    cryptography.doProofOfWork(item.object, item.nonceTrialsPerByte, item.extraBytes,
+                        ProofOfWorkService.this);
+                }
+            }
+        }, delayInMilliseconds);
+    }
+
+    public void doProofOfWork(ObjectMessage object) {
+        doProofOfWork(null, object);
+    }
+
+    public void doProofOfWork(BitmessageAddress recipient, ObjectMessage object) {
+        Pubkey pubkey = recipient == null ? null : recipient.getPubkey();
+
+        long nonceTrialsPerByte = pubkey == null ? NETWORK_NONCE_TRIALS_PER_BYTE : pubkey.getNonceTrialsPerByte();
+        long extraBytes = pubkey == null ? NETWORK_EXTRA_BYTES : pubkey.getExtraBytes();
+
+        powRepo.putObject(object, nonceTrialsPerByte, extraBytes);
+        if (object.getPayload() instanceof PlaintextHolder) {
+            Plaintext plaintext = ((PlaintextHolder) object.getPayload()).getPlaintext();
+            plaintext.setInitialHash(cryptography.getInitialHash(object));
+            messageRepo.save(plaintext);
+        }
+        cryptography.doProofOfWork(object, nonceTrialsPerByte, extraBytes, this);
+    }
+
+    public void doProofOfWorkWithAck(Plaintext plaintext, long expirationTime) {
+        final ObjectMessage ack = plaintext.getAckMessage();
+        messageRepo.save(plaintext);
+        Item item = new Item(ack, NETWORK_NONCE_TRIALS_PER_BYTE, NETWORK_EXTRA_BYTES,
+            expirationTime, plaintext);
+        powRepo.putObject(item);
+        cryptography.doProofOfWork(ack, NETWORK_NONCE_TRIALS_PER_BYTE, NETWORK_EXTRA_BYTES, this);
+    }
+
+    @Override
+    public void onNonceCalculated(byte[] initialHash, byte[] nonce) {
+        Item item = powRepo.getItem(initialHash);
+        if (item.message == null) {
+            ObjectMessage object = powRepo.getItem(initialHash).object;
+            object.setNonce(nonce);
+            Plaintext plaintext = messageRepo.getMessage(initialHash);
+            if (plaintext != null) {
+                plaintext.setInventoryVector(object.getInventoryVector());
+                plaintext.updateNextTry();
+                ctx.getLabeler().markAsSent(plaintext);
+                messageRepo.save(plaintext);
+            }
+            try {
+                ctx.getNetworkListener().receive(object);
+            } catch (IOException e) {
+                LOG.debug(e.getMessage(), e);
+            }
+            ctx.getInventory().storeObject(object);
+            ctx.getNetworkHandler().offer(object.getInventoryVector());
+        } else {
+            item.message.getAckMessage().setNonce(nonce);
+            final ObjectMessage object = new ObjectMessage.Builder()
+                .stream(item.message.getStream())
+                .expiresTime(item.expirationTime)
+                .payload(new Msg(item.message))
+                .build();
+            if (object.isSigned()) {
+                object.sign(item.message.getFrom().getPrivateKey());
+            }
+            if (object.getPayload() instanceof Encrypted) {
+                object.encrypt(item.message.getTo().getPubkey());
+            }
+            doProofOfWork(item.message.getTo(), object);
+        }
+        powRepo.removeObject(initialHash);
+    }
+
+    @Override
+    public void setContext(InternalContext ctx) {
+        this.ctx = ctx;
+        this.cryptography = cryptography();
+        this.powRepo = ctx.getProofOfWorkRepository();
+        this.messageRepo = ctx.getMessageRepository();
+    }
+}

core/src/main/java/ch/dissem/bitmessage/entity/Addr.java

@@ -21,6 +21,7 @@ import ch.dissem.bitmessage.utils.Encode;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -29,6 +30,8 @@ import java.util.List;
  * The 'addr' command holds a list of known active Bitmessage nodes.
  */
 public class Addr implements MessagePayload {
+    private static final long serialVersionUID = -5117688017050138720L;
+
     private final List<NetworkAddress> addresses;
 
     private Addr(Builder builder) {
@@ -45,18 +48,23 @@ public class Addr implements MessagePayload {
     }
 
     @Override
-    public void write(OutputStream stream) throws IOException {
-        Encode.varInt(addresses.size(), stream);
+    public void write(OutputStream out) throws IOException {
+        Encode.varInt(addresses.size(), out);
         for (NetworkAddress address : addresses) {
-            address.write(stream);
+            address.write(out);
+        }
+    }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        Encode.varInt(addresses.size(), buffer);
+        for (NetworkAddress address : addresses) {
+            address.write(buffer);
         }
     }
 
     public static final class Builder {
-        private List<NetworkAddress> addresses = new ArrayList<NetworkAddress>();
-
-        public Builder() {
-        }
+        private List<NetworkAddress> addresses = new ArrayList<>();
 
         public Builder addresses(Collection<NetworkAddress> addresses){
             this.addresses.addAll(addresses);

core/src/main/java/ch/dissem/bitmessage/entity/BitmessageAddress.java

@@ -17,24 +17,35 @@
 package ch.dissem.bitmessage.entity;
 
 import ch.dissem.bitmessage.entity.payload.Pubkey;
+import ch.dissem.bitmessage.entity.payload.Pubkey.Feature;
 import ch.dissem.bitmessage.entity.payload.V4Pubkey;
 import ch.dissem.bitmessage.entity.valueobject.PrivateKey;
-import ch.dissem.bitmessage.utils.*;
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.utils.AccessCounter;
+import ch.dissem.bitmessage.utils.Base58;
+import ch.dissem.bitmessage.utils.Bytes;
+import ch.dissem.bitmessage.utils.Encode;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Objects;
 
 import static ch.dissem.bitmessage.utils.Decode.bytes;
 import static ch.dissem.bitmessage.utils.Decode.varInt;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 
 /**
  * A Bitmessage address. Can be a user's private address, an address string without public keys or a recipient's address
  * holding private keys.
  */
-public class BitmessageAddress {
+public class BitmessageAddress implements Serializable {
+    private static final long serialVersionUID = 2386328540805994064L;
+
     private final long version;
     private final long stream;
     private final byte[] ripe;
@@ -51,6 +62,7 @@ public class BitmessageAddress {
 
     private String alias;
     private boolean subscribed;
+    private boolean chan;
 
     BitmessageAddress(long version, long stream, byte[] ripe) {
         try {
@@ -62,31 +74,63 @@ public class BitmessageAddress {
             Encode.varInt(version, os);
             Encode.varInt(stream, os);
             if (version < 4) {
-                byte[] checksum = Security.sha512(os.toByteArray(), ripe);
+                byte[] checksum = cryptography().sha512(os.toByteArray(), ripe);
                 this.tag = null;
                 this.publicDecryptionKey = Arrays.copyOfRange(checksum, 0, 32);
             } else {
                 // for tag and decryption key, the checksum has to be created with 0x00 padding
-                byte[] checksum = Security.doubleSha512(os.toByteArray(), ripe);
+                byte[] checksum = cryptography().doubleSha512(os.toByteArray(), ripe);
                 this.tag = Arrays.copyOfRange(checksum, 32, 64);
                 this.publicDecryptionKey = Arrays.copyOfRange(checksum, 0, 32);
             }
             // but for the address and its checksum they need to be stripped
             int offset = Bytes.numberOfLeadingZeros(ripe);
             os.write(ripe, offset, ripe.length - offset);
-            byte[] checksum = Security.doubleSha512(os.toByteArray());
+            byte[] checksum = cryptography().doubleSha512(os.toByteArray());
             os.write(checksum, 0, 4);
             this.address = "BM-" + Base58.encode(os.toByteArray());
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
-    BitmessageAddress(Pubkey publicKey) {
+    public BitmessageAddress(Pubkey publicKey) {
         this(publicKey.getVersion(), publicKey.getStream(), publicKey.getRipe());
         this.pubkey = publicKey;
     }
 
+    public BitmessageAddress(String address, String passphrase) {
+        this(address);
+        this.privateKey = new PrivateKey(this, passphrase);
+        this.pubkey = this.privateKey.getPubkey();
+        if (!Arrays.equals(ripe, privateKey.getPubkey().getRipe())) {
+            throw new IllegalArgumentException("Wrong address or passphrase");
+        }
+    }
+
+    public static BitmessageAddress chan(String address, String passphrase) {
+        BitmessageAddress result = new BitmessageAddress(address, passphrase);
+        result.chan = true;
+        return result;
+    }
+
+    public static BitmessageAddress chan(long stream, String passphrase) {
+        PrivateKey privateKey = new PrivateKey(Pubkey.LATEST_VERSION, stream, passphrase);
+        BitmessageAddress result = new BitmessageAddress(privateKey);
+        result.chan = true;
+        return result;
+    }
+
+    public static List<BitmessageAddress> deterministic(String passphrase, int numberOfAddresses,
+                                                        long version, long stream, boolean shorter) {
+        List<BitmessageAddress> result = new ArrayList<>(numberOfAddresses);
+        List<PrivateKey> privateKeys = PrivateKey.deterministic(passphrase, numberOfAddresses, version, stream, shorter);
+        for (PrivateKey pk : privateKeys) {
+            result.add(new BitmessageAddress(pk));
+        }
+        return result;
+    }
+
     public BitmessageAddress(PrivateKey privateKey) {
         this(privateKey.getPubkey());
         this.privateKey = privateKey;
@@ -103,23 +147,23 @@ public class BitmessageAddress {
             this.ripe = Bytes.expand(bytes(in, bytes.length - counter.length() - 4), 20);
 
             // test checksum
-            byte[] checksum = Security.doubleSha512(bytes, bytes.length - 4);
+            byte[] checksum = cryptography().doubleSha512(bytes, bytes.length - 4);
             byte[] expectedChecksum = bytes(in, 4);
             for (int i = 0; i < 4; i++) {
                 if (expectedChecksum[i] != checksum[i])
                     throw new IllegalArgumentException("Checksum of address failed");
             }
             if (version < 4) {
-                checksum = Security.sha512(Arrays.copyOfRange(bytes, 0, counter.length()), ripe);
+                checksum = cryptography().sha512(Arrays.copyOfRange(bytes, 0, counter.length()), ripe);
                 this.tag = null;
                 this.publicDecryptionKey = Arrays.copyOfRange(checksum, 0, 32);
             } else {
-                checksum = Security.doubleSha512(Arrays.copyOfRange(bytes, 0, counter.length()), ripe);
+                checksum = cryptography().doubleSha512(Arrays.copyOfRange(bytes, 0, counter.length()), ripe);
                 this.tag = Arrays.copyOfRange(checksum, 32, 64);
                 this.publicDecryptionKey = Arrays.copyOfRange(checksum, 0, 32);
             }
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
@@ -129,9 +173,9 @@ public class BitmessageAddress {
             Encode.varInt(version, out);
             Encode.varInt(stream, out);
             out.write(ripe);
-            return Arrays.copyOfRange(Security.doubleSha512(out.toByteArray()), 32, 64);
+            return Arrays.copyOfRange(cryptography().doubleSha512(out.toByteArray()), 32, 64);
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
@@ -182,7 +226,7 @@ public class BitmessageAddress {
 
     @Override
     public String toString() {
-        return alias != null ? alias : address;
+        return alias == null ? address : alias;
     }
 
     public byte[] getRipe() {
@@ -215,4 +259,19 @@ public class BitmessageAddress {
     public void setSubscribed(boolean subscribed) {
         this.subscribed = subscribed;
     }
+
+    public boolean isChan() {
+        return chan;
+    }
+
+    public void setChan(boolean chan) {
+        this.chan = chan;
+    }
+
+    public boolean has(Feature feature) {
+        if (pubkey == null || feature == null) {
+            return false;
+        }
+        return feature.isActive(pubkey.getBehaviorBitfield());
+    }
 }

core/src/main/java/ch/dissem/bitmessage/entity/CustomMessage.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.entity;
+
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.utils.AccessCounter;
+import ch.dissem.bitmessage.utils.Encode;
+
+import java.io.*;
+import java.nio.ByteBuffer;
+
+import static ch.dissem.bitmessage.utils.Decode.bytes;
+import static ch.dissem.bitmessage.utils.Decode.varString;
+
+/**
+ * @author Christian Basler
+ */
+public class CustomMessage implements MessagePayload {
+    private static final long serialVersionUID = -8932056829480326011L;
+
+    public static final String COMMAND_ERROR = "ERROR";
+
+    private final String command;
+    private final byte[] data;
+
+    public CustomMessage(String command) {
+        this.command = command;
+        this.data = null;
+    }
+
+    public CustomMessage(String command, byte[] data) {
+        this.command = command;
+        this.data = data;
+    }
+
+    public static CustomMessage read(InputStream in, int length) throws IOException {
+        AccessCounter counter = new AccessCounter();
+        return new CustomMessage(varString(in, counter), bytes(in, length - counter.length()));
+    }
+
+    @Override
+    public Command getCommand() {
+        return Command.CUSTOM;
+    }
+
+    public String getCustomCommand() {
+        return command;
+    }
+
+    public byte[] getData() {
+        if (data != null) {
+            return data;
+        } else {
+            try {
+                ByteArrayOutputStream out = new ByteArrayOutputStream();
+                write(out);
+                return out.toByteArray();
+            } catch (IOException e) {
+                throw new ApplicationException(e);
+            }
+        }
+    }
+
+    @Override
+    public void write(OutputStream out) throws IOException {
+        if (data != null) {
+            Encode.varString(command, out);
+            out.write(data);
+        } else {
+            throw new ApplicationException("Tried to write custom message without data. " +
+                    "Programmer: did you forget to override #write()?");
+        }
+    }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        if (data != null) {
+            Encode.varString(command, buffer);
+            buffer.put(data);
+        } else {
+            throw new ApplicationException("Tried to write custom message without data. " +
+                    "Programmer: did you forget to override #write()?");
+        }
+    }
+
+    public boolean isError() {
+        return COMMAND_ERROR.equals(command);
+    }
+
+    public static CustomMessage error(String message) {
+        try {
+            return new CustomMessage(COMMAND_ERROR, message.getBytes("UTF-8"));
+        } catch (UnsupportedEncodingException e) {
+            throw new ApplicationException(e);
+        }
+    }
+}

core/src/main/java/ch/dissem/bitmessage/entity/GetData.java

@@ -21,6 +21,7 @@ import ch.dissem.bitmessage.utils.Encode;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -28,6 +29,10 @@ import java.util.List;
  * The 'getdata' command is used to request objects from a node.
  */
 public class GetData implements MessagePayload {
+    private static final long serialVersionUID = 1433878785969631061L;
+
+    public static final int MAX_INVENTORY_SIZE = 50_000;
+
     List<InventoryVector> inventory;
 
     private GetData(Builder builder) {
@@ -44,19 +49,24 @@ public class GetData implements MessagePayload {
     }
 
     @Override
-    public void write(OutputStream stream) throws IOException {
-        Encode.varInt(inventory.size(), stream);
+    public void write(OutputStream out) throws IOException {
+        Encode.varInt(inventory.size(), out);
         for (InventoryVector iv : inventory) {
-            iv.write(stream);
+            iv.write(out);
+        }
+    }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        Encode.varInt(inventory.size(), buffer);
+        for (InventoryVector iv : inventory) {
+            iv.write(buffer);
         }
     }
 
     public static final class Builder {
         private List<InventoryVector> inventory = new LinkedList<>();
 
-        public Builder() {
-        }
-
         public Builder addInventoryVector(InventoryVector inventoryVector) {
             this.inventory.add(inventoryVector);
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/Inv.java

@@ -21,6 +21,7 @@ import ch.dissem.bitmessage.utils.Encode;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -28,6 +29,8 @@ import java.util.List;
  * The 'inv' command holds up to 50000 inventory vectors, i.e. hashes of inventory items.
  */
 public class Inv implements MessagePayload {
+    private static final long serialVersionUID = 3662992522956947145L;
+
     private List<InventoryVector> inventory;
 
     private Inv(Builder builder) {
@@ -44,19 +47,24 @@ public class Inv implements MessagePayload {
     }
 
     @Override
-    public void write(OutputStream stream) throws IOException {
-        Encode.varInt(inventory.size(), stream);
+    public void write(OutputStream out) throws IOException {
+        Encode.varInt(inventory.size(), out);
         for (InventoryVector iv : inventory) {
-            iv.write(stream);
+            iv.write(out);
+        }
+    }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        Encode.varInt(inventory.size(), buffer);
+        for (InventoryVector iv : inventory) {
+            iv.write(buffer);
         }
     }
 
     public static final class Builder {
         private List<InventoryVector> inventory = new LinkedList<>();
 
-        public Builder() {
-        }
-
         public Builder addInventoryVector(InventoryVector inventoryVector) {
             this.inventory.add(inventoryVector);
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/MessagePayload.java

@@ -23,6 +23,6 @@ public interface MessagePayload extends Streamable {
     Command getCommand();
 
     enum Command {
-        VERSION, VERACK, ADDR, INV, GETDATA, OBJECT
+        VERSION, VERACK, ADDR, INV, GETDATA, OBJECT, CUSTOM
     }
 }

core/src/main/java/ch/dissem/bitmessage/entity/NetworkMessage.java

@@ -16,22 +16,25 @@
 
 package ch.dissem.bitmessage.entity;
 
+import ch.dissem.bitmessage.exception.ApplicationException;
 import ch.dissem.bitmessage.utils.Encode;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.security.GeneralSecurityException;
 import java.security.NoSuchAlgorithmException;
 import java.security.NoSuchProviderException;
 
-import static ch.dissem.bitmessage.utils.Security.sha512;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 
 /**
  * A network message is exchanged between two nodes.
  */
 public class NetworkMessage implements Streamable {
+    private static final long serialVersionUID = 702708857104464809L;
+
     /**
      * Magic value indicating message origin network, and used to seek to next message when stream state is unknown
      */
@@ -48,7 +51,7 @@ public class NetworkMessage implements Streamable {
      * First 4 bytes of sha512(payload)
      */
     private byte[] getChecksum(byte[] bytes) throws NoSuchProviderException, NoSuchAlgorithmException {
-        byte[] d = sha512(bytes);
+        byte[] d = cryptography().sha512(bytes);
         return new byte[]{d[0], d[1], d[2], d[3]};
     }
 
@@ -71,9 +74,7 @@ public class NetworkMessage implements Streamable {
             out.write('\0');
         }
 
-        ByteArrayOutputStream payloadStream = new ByteArrayOutputStream();
-        payload.write(payloadStream);
-        byte[] payloadBytes = payloadStream.toByteArray();
+        byte[] payloadBytes = Encode.bytes(payload);
 
         // Length of payload in number of bytes. Because of other restrictions, there is no reason why this length would
         // ever be larger than 1600003 bytes. Some clients include a sanity-check to avoid processing messages which are
@@ -84,10 +85,67 @@ public class NetworkMessage implements Streamable {
         try {
             out.write(getChecksum(payloadBytes));
         } catch (GeneralSecurityException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
 
         // message payload
         out.write(payloadBytes);
     }
+
+    /**
+     * A more efficient implementation of the write method, writing header data to the provided buffer and returning
+     * a new buffer containing the payload.
+     *
+     * @param headerBuffer where the header data is written to (24 bytes)
+     * @return a buffer containing the payload, ready to be read.
+     */
+    public ByteBuffer writeHeaderAndGetPayloadBuffer(ByteBuffer headerBuffer) {
+        return ByteBuffer.wrap(writeHeader(headerBuffer));
+    }
+
+    /**
+     * For improved memory efficiency, you should use {@link #writeHeaderAndGetPayloadBuffer(ByteBuffer)}
+     * and write the header buffer as well as the returned payload buffer into the channel.
+     *
+     * @param buffer where everything gets written to. Needs to be large enough for the whole message
+     *               to be written.
+     */
+    @Override
+    public void write(ByteBuffer buffer) {
+        byte[] payloadBytes = writeHeader(buffer);
+        buffer.put(payloadBytes);
+    }
+
+    private byte[] writeHeader(ByteBuffer out) {
+        // magic
+        Encode.int32(MAGIC, out);
+
+        // ASCII string identifying the packet content, NULL padded (non-NULL padding results in packet rejected)
+        String command = payload.getCommand().name().toLowerCase();
+        try {
+            out.put(command.getBytes("ASCII"));
+        } catch (UnsupportedEncodingException e) {
+            throw new ApplicationException(e);
+        }
+        for (int i = command.length(); i < 12; i++) {
+            out.put((byte) 0);
+        }
+
+        byte[] payloadBytes = Encode.bytes(payload);
+
+        // Length of payload in number of bytes. Because of other restrictions, there is no reason why this length would
+        // ever be larger than 1600003 bytes. Some clients include a sanity-check to avoid processing messages which are
+        // larger than this.
+        Encode.int32(payloadBytes.length, out);
+
+        // checksum
+        try {
+            out.put(getChecksum(payloadBytes));
+        } catch (GeneralSecurityException e) {
+            throw new ApplicationException(e);
+        }
+
+        // message payload
+        return payloadBytes;
+    }
 }

core/src/main/java/ch/dissem/bitmessage/entity/ObjectMessage.java

@@ -21,19 +21,26 @@ import ch.dissem.bitmessage.entity.payload.ObjectType;
 import ch.dissem.bitmessage.entity.payload.Pubkey;
 import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
 import ch.dissem.bitmessage.entity.valueobject.PrivateKey;
+import ch.dissem.bitmessage.exception.ApplicationException;
 import ch.dissem.bitmessage.exception.DecryptionFailedException;
 import ch.dissem.bitmessage.utils.Bytes;
 import ch.dissem.bitmessage.utils.Encode;
-import ch.dissem.bitmessage.utils.Security;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.Objects;
+
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 
 /**
  * The 'object' command sends an object that is shared throughout the network.
  */
 public class ObjectMessage implements MessagePayload {
+    private static final long serialVersionUID = 2495752480120659139L;
+
     private byte[] nonce;
     private long expiresTime;
     private long objectType;
@@ -51,7 +58,7 @@ public class ObjectMessage implements MessagePayload {
         expiresTime = builder.expiresTime;
         objectType = builder.objectType;
         version = builder.payload.getVersion();
-        stream = builder.streamNumber;
+        stream = builder.streamNumber > 0 ? builder.streamNumber : builder.payload.getStream();
         payload = builder.payload;
     }
 
@@ -89,7 +96,9 @@ public class ObjectMessage implements MessagePayload {
     }
 
     public InventoryVector getInventoryVector() {
-        return new InventoryVector(Bytes.truncate(Security.doubleSha512(nonce, getPayloadBytesWithoutNonce()), 32));
+        return new InventoryVector(
+                Bytes.truncate(cryptography().doubleSha512(nonce, getPayloadBytesWithoutNonce()), 32)
+        );
     }
 
     private boolean isEncrypted() {
@@ -107,13 +116,13 @@ public class ObjectMessage implements MessagePayload {
             payload.writeBytesToSign(out);
             return out.toByteArray();
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
     public void sign(PrivateKey key) {
         if (payload.isSigned()) {
-            payload.setSignature(Security.getSignature(getBytesToSign(), key));
+            payload.setSignature(cryptography().getSignature(getBytesToSign(), key));
         }
     }
 
@@ -141,21 +150,35 @@ public class ObjectMessage implements MessagePayload {
                 ((Encrypted) payload).encrypt(publicKey.getEncryptionKey());
             }
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
     public boolean isSignatureValid(Pubkey pubkey) throws IOException {
         if (isEncrypted()) throw new IllegalStateException("Payload must be decrypted first");
-        return Security.isSignatureValid(getBytesToSign(), payload.getSignature(), pubkey);
+        return cryptography().isSignatureValid(getBytesToSign(), payload.getSignature(), pubkey);
     }
 
     @Override
     public void write(OutputStream out) throws IOException {
-        out.write(nonce);
+        if (nonce == null) {
+            out.write(new byte[8]);
+        } else {
+            out.write(nonce);
+        }
         out.write(getPayloadBytesWithoutNonce());
     }
 
+    @Override
+    public void write(ByteBuffer buffer) {
+        if (nonce == null) {
+            buffer.put(new byte[8]);
+        } else {
+            buffer.put(nonce);
+        }
+        buffer.put(getPayloadBytesWithoutNonce());
+    }
+
     private void writeHeaderWithoutNonce(OutputStream out) throws IOException {
         Encode.int64(expiresTime, out);
         Encode.int32(objectType, out);
@@ -173,7 +196,7 @@ public class ObjectMessage implements MessagePayload {
             }
             return payloadBytes;
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
@@ -184,9 +207,6 @@ public class ObjectMessage implements MessagePayload {
         private long streamNumber;
         private ObjectPayload payload;
 
-        public Builder() {
-        }
-
         public Builder nonce(byte[] nonce) {
             this.nonce = nonce;
             return this;
@@ -223,4 +243,29 @@ public class ObjectMessage implements MessagePayload {
             return new ObjectMessage(this);
         }
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        ObjectMessage that = (ObjectMessage) o;
+
+        return expiresTime == that.expiresTime &&
+                objectType == that.objectType &&
+                version == that.version &&
+                stream == that.stream &&
+                Objects.equals(payload, that.payload);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = Arrays.hashCode(nonce);
+        result = 31 * result + (int) (expiresTime ^ (expiresTime >>> 32));
+        result = 31 * result + (int) (objectType ^ (objectType >>> 32));
+        result = 31 * result + (int) (version ^ (version >>> 32));
+        result = 31 * result + (int) (stream ^ (stream >>> 32));
+        result = 31 * result + (payload != null ? payload.hashCode() : 0);
+        return result;
+    }
 }

core/src/main/java/ch/dissem/bitmessage/entity/Plaintext.java

@@ -16,24 +16,33 @@
 
 package ch.dissem.bitmessage.entity;
 
+import ch.dissem.bitmessage.entity.payload.Msg;
+import ch.dissem.bitmessage.entity.payload.Pubkey.Feature;
 import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
 import ch.dissem.bitmessage.entity.valueobject.Label;
+import ch.dissem.bitmessage.exception.ApplicationException;
 import ch.dissem.bitmessage.factory.Factory;
-import ch.dissem.bitmessage.utils.Decode;
-import ch.dissem.bitmessage.utils.Encode;
+import ch.dissem.bitmessage.utils.*;
 
 import java.io.*;
+import java.nio.ByteBuffer;
 import java.util.*;
+import java.util.Collections;
+
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 
 /**
  * The unencrypted message to be sent by 'msg' or 'broadcast'.
  */
 public class Plaintext implements Streamable {
+    private static final long serialVersionUID = -5325729856394951079L;
+
     private final Type type;
     private final BitmessageAddress from;
     private final long encoding;
     private final byte[] message;
-    private final byte[] ack;
+    private final byte[] ackData;
+    private ObjectMessage ackMessage;
     private Object id;
     private InventoryVector inventoryVector;
     private BitmessageAddress to;
@@ -43,6 +52,11 @@ public class Plaintext implements Streamable {
     private Long received;
 
     private Set<Label> labels;
+    private byte[] initialHash;
+
+    private long ttl;
+    private int retries;
+    private Long nextTry;
 
     private Plaintext(Builder builder) {
         id = builder.id;
@@ -52,34 +66,44 @@ public class Plaintext implements Streamable {
         to = builder.to;
         encoding = builder.encoding;
         message = builder.message;
-        ack = builder.ack;
+        ackData = builder.ackData;
+        if (builder.ackMessage != null && builder.ackMessage.length > 0) {
+            ackMessage = Factory.getObjectMessage(
+                3,
+                new ByteArrayInputStream(builder.ackMessage),
+                builder.ackMessage.length);
+        }
         signature = builder.signature;
         status = builder.status;
         sent = builder.sent;
         received = builder.received;
         labels = builder.labels;
+        ttl = builder.ttl;
+        retries = builder.retries;
+        nextTry = builder.nextTry;
     }
 
     public static Plaintext read(Type type, InputStream in) throws IOException {
         return readWithoutSignature(type, in)
-                .signature(Decode.varBytes(in))
-                .build();
+            .signature(Decode.varBytes(in))
+            .received(UnixTime.now())
+            .build();
     }
 
     public static Plaintext.Builder readWithoutSignature(Type type, InputStream in) throws IOException {
         long version = Decode.varInt(in);
         return new Builder(type)
-                .addressVersion(version)
-                .stream(Decode.varInt(in))
-                .behaviorBitfield(Decode.int32(in))
-                .publicSigningKey(Decode.bytes(in, 64))
-                .publicEncryptionKey(Decode.bytes(in, 64))
-                .nonceTrialsPerByte(version >= 3 ? Decode.varInt(in) : 0)
-                .extraBytes(version >= 3 ? Decode.varInt(in) : 0)
-                .destinationRipe(type == Type.MSG ? Decode.bytes(in, 20) : null)
-                .encoding(Decode.varInt(in))
-                .message(Decode.varBytes(in))
-                .ack(type == Type.MSG ? Decode.varBytes(in) : null);
+            .addressVersion(version)
+            .stream(Decode.varInt(in))
+            .behaviorBitfield(Decode.int32(in))
+            .publicSigningKey(Decode.bytes(in, 64))
+            .publicEncryptionKey(Decode.bytes(in, 64))
+            .nonceTrialsPerByte(version >= 3 ? Decode.varInt(in) : 0)
+            .extraBytes(version >= 3 ? Decode.varInt(in) : 0)
+            .destinationRipe(type == Type.MSG ? Decode.bytes(in, 20) : null)
+            .encoding(Decode.varInt(in))
+            .message(Decode.varBytes(in))
+            .ackMessage(type == Type.MSG ? Decode.varBytes(in) : null);
     }
 
     public InventoryVector getInventoryVector() {
@@ -108,9 +132,9 @@ public class Plaintext implements Streamable {
 
     public void setTo(BitmessageAddress to) {
         if (this.to.getVersion() != 0)
-            throw new RuntimeException("Correct address already set");
+            throw new IllegalStateException("Correct address already set");
         if (!Arrays.equals(this.to.getRipe(), to.getRipe())) {
-            throw new RuntimeException("RIPEs don't match");
+            throw new IllegalArgumentException("RIPEs don't match");
         }
         this.to = to;
     }
@@ -131,6 +155,15 @@ public class Plaintext implements Streamable {
         this.signature = signature;
     }
 
+    public boolean isUnread() {
+        for (Label label : labels) {
+            if (label.getType() == Label.Type.UNREAD) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     public void write(OutputStream out, boolean includeSignature) throws IOException {
         Encode.varInt(from.getVersion(), out);
         Encode.varInt(from.getStream(), out);
@@ -148,8 +181,13 @@ public class Plaintext implements Streamable {
         Encode.varInt(message.length, out);
         out.write(message);
         if (type == Type.MSG) {
-            Encode.varInt(ack.length, out);
-            out.write(ack);
+            if (to.has(Feature.DOES_ACK) && getAckMessage() != null) {
+                ByteArrayOutputStream ack = new ByteArrayOutputStream();
+                getAckMessage().write(ack);
+                Encode.varBytes(ack.toByteArray(), out);
+            } else {
+                Encode.varInt(0, out);
+            }
         }
         if (includeSignature) {
             if (signature == null) {
@@ -161,11 +199,49 @@ public class Plaintext implements Streamable {
         }
     }
 
+    public void write(ByteBuffer buffer, boolean includeSignature) {
+        Encode.varInt(from.getVersion(), buffer);
+        Encode.varInt(from.getStream(), buffer);
+        Encode.int32(from.getPubkey().getBehaviorBitfield(), buffer);
+        buffer.put(from.getPubkey().getSigningKey(), 1, 64);
+        buffer.put(from.getPubkey().getEncryptionKey(), 1, 64);
+        if (from.getVersion() >= 3) {
+            Encode.varInt(from.getPubkey().getNonceTrialsPerByte(), buffer);
+            Encode.varInt(from.getPubkey().getExtraBytes(), buffer);
+        }
+        if (type == Type.MSG) {
+            buffer.put(to.getRipe());
+        }
+        Encode.varInt(encoding, buffer);
+        Encode.varInt(message.length, buffer);
+        buffer.put(message);
+        if (type == Type.MSG) {
+            if (to.has(Feature.DOES_ACK) && getAckMessage() != null) {
+                Encode.varBytes(Encode.bytes(getAckMessage()), buffer);
+            } else {
+                Encode.varInt(0, buffer);
+            }
+        }
+        if (includeSignature) {
+            if (signature == null) {
+                Encode.varInt(0, buffer);
+            } else {
+                Encode.varInt(signature.length, buffer);
+                buffer.put(signature);
+            }
+        }
+    }
+
     @Override
     public void write(OutputStream out) throws IOException {
         write(out, true);
     }
 
+    @Override
+    public void write(ByteBuffer buffer) {
+        write(buffer, true);
+    }
+
     public Object getId() {
         return id;
     }
@@ -188,9 +264,38 @@ public class Plaintext implements Streamable {
     }
 
     public void setStatus(Status status) {
+        if (status != Status.RECEIVED && sent == null && status != Status.DRAFT) {
+            sent = UnixTime.now();
+        }
         this.status = status;
     }
 
+    public long getTTL() {
+        return ttl;
+    }
+
+    public int getRetries() {
+        return retries;
+    }
+
+    public Long getNextTry() {
+        return nextTry;
+    }
+
+    public void updateNextTry() {
+        if (to != null) {
+            if (nextTry == null) {
+                if (sent != null && to.has(Feature.DOES_ACK)) {
+                    nextTry = UnixTime.now(+ttl);
+                    retries++;
+                }
+            } else {
+                nextTry = nextTry + (1 << retries) * ttl;
+                retries++;
+            }
+        }
+    }
+
     public String getSubject() {
         Scanner s = new Scanner(new ByteArrayInputStream(message), "UTF-8");
         String firstLine = s.nextLine();
@@ -211,7 +316,7 @@ public class Plaintext implements Streamable {
             }
             return text;
         } catch (UnsupportedEncodingException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
@@ -221,20 +326,20 @@ public class Plaintext implements Streamable {
         if (o == null || getClass() != o.getClass()) return false;
         Plaintext plaintext = (Plaintext) o;
         return Objects.equals(encoding, plaintext.encoding) &&
-                Objects.equals(from, plaintext.from) &&
-                Arrays.equals(message, plaintext.message) &&
-                Arrays.equals(ack, plaintext.ack) &&
-                Arrays.equals(to.getRipe(), plaintext.to.getRipe()) &&
-                Arrays.equals(signature, plaintext.signature) &&
-                Objects.equals(status, plaintext.status) &&
-                Objects.equals(sent, plaintext.sent) &&
-                Objects.equals(received, plaintext.received) &&
-                Objects.equals(labels, plaintext.labels);
+            Objects.equals(from, plaintext.from) &&
+            Arrays.equals(message, plaintext.message) &&
+            Objects.equals(getAckMessage(), plaintext.getAckMessage()) &&
+            Arrays.equals(to == null ? null : to.getRipe(), plaintext.to == null ? null : plaintext.to.getRipe()) &&
+            Arrays.equals(signature, plaintext.signature) &&
+            Objects.equals(status, plaintext.status) &&
+            Objects.equals(sent, plaintext.sent) &&
+            Objects.equals(received, plaintext.received) &&
+            Objects.equals(labels, plaintext.labels);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(from, encoding, message, ack, to, signature, status, sent, received, labels);
+        return Objects.hash(from, encoding, message, ackData, to, signature, status, sent, received, labels);
     }
 
     public void addLabels(Label... labels) {
@@ -245,10 +350,41 @@ public class Plaintext implements Streamable {
 
     public void addLabels(Collection<Label> labels) {
         if (labels != null) {
-            this.labels.addAll(labels);
+            for (Label label : labels) {
+                this.labels.add(label);
+            }
         }
     }
 
+    public void removeLabel(Label.Type type) {
+        Iterator<Label> iterator = labels.iterator();
+        while (iterator.hasNext()) {
+            Label label = iterator.next();
+            if (label.getType() == type) {
+                iterator.remove();
+            }
+        }
+    }
+
+    public byte[] getAckData() {
+        return ackData;
+    }
+
+    public ObjectMessage getAckMessage() {
+        if (ackMessage == null) {
+            ackMessage = Factory.createAck(this);
+        }
+        return ackMessage;
+    }
+
+    public void setInitialHash(byte[] initialHash) {
+        this.initialHash = initialHash;
+    }
+
+    public byte[] getInitialHash() {
+        return initialHash;
+    }
+
     public enum Encoding {
         IGNORE(0), TRIVIAL(1), SIMPLE(2);
 
@@ -293,12 +429,16 @@ public class Plaintext implements Streamable {
         private byte[] destinationRipe;
         private long encoding;
         private byte[] message = new byte[0];
-        private byte[] ack = new byte[0];
+        private byte[] ackData;
+        private byte[] ackMessage;
         private byte[] signature;
         private long sent;
         private long received;
         private Status status;
         private Set<Label> labels = new HashSet<>();
+        private long ttl;
+        private int retries;
+        private Long nextTry;
 
         public Builder(Type type) {
             this.type = type;
@@ -382,7 +522,7 @@ public class Plaintext implements Streamable {
                 this.encoding = Encoding.SIMPLE.getCode();
                 this.message = ("Subject:" + subject + '\n' + "Body:" + message).getBytes("UTF-8");
             } catch (UnsupportedEncodingException e) {
-                throw new RuntimeException(e);
+                throw new ApplicationException(e);
             }
             return this;
         }
@@ -392,9 +532,16 @@ public class Plaintext implements Streamable {
             return this;
         }
 
-        public Builder ack(byte[] ack) {
-            if (type != Type.MSG && ack != null) throw new IllegalArgumentException("ack only allowed for msg");
-            this.ack = ack;
+        public Builder ackMessage(byte[] ack) {
+            if (type != Type.MSG && ack != null) throw new IllegalArgumentException("ackMessage only allowed for msg");
+            this.ackMessage = ack;
+            return this;
+        }
+
+        public Builder ackData(byte[] ackData) {
+            if (type != Type.MSG && ackData != null)
+                throw new IllegalArgumentException("ackMessage only allowed for msg");
+            this.ackData = ackData;
             return this;
         }
 
@@ -423,21 +570,42 @@ public class Plaintext implements Streamable {
             return this;
         }
 
+        public Builder ttl(long ttl) {
+            this.ttl = ttl;
+            return this;
+        }
+
+        public Builder retries(int retries) {
+            this.retries = retries;
+            return this;
+        }
+
+        public Builder nextTry(Long nextTry) {
+            this.nextTry = nextTry;
+            return this;
+        }
+
         public Plaintext build() {
             if (from == null) {
                 from = new BitmessageAddress(Factory.createPubkey(
-                        addressVersion,
-                        stream,
-                        publicSigningKey,
-                        publicEncryptionKey,
-                        nonceTrialsPerByte,
-                        extraBytes,
-                        behaviorBitfield
+                    addressVersion,
+                    stream,
+                    publicSigningKey,
+                    publicEncryptionKey,
+                    nonceTrialsPerByte,
+                    extraBytes,
+                    behaviorBitfield
                 ));
             }
-            if (to == null && type != Type.BROADCAST) {
+            if (to == null && type != Type.BROADCAST && destinationRipe != null) {
                 to = new BitmessageAddress(0, 0, destinationRipe);
             }
+            if (type == Type.MSG && ackMessage == null && ackData == null) {
+                ackData = cryptography().randomBytes(Msg.ACK_LENGTH);
+            }
+            if (ttl <= 0) {
+                ttl = TTL.msg();
+            }
             return new Plaintext(this);
         }
     }

core/src/main/java/ch/dissem/bitmessage/entity/Streamable.java

@@ -18,10 +18,14 @@ package ch.dissem.bitmessage.entity;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.Serializable;
+import java.nio.ByteBuffer;
 
 /**
  * An object that can be written to an {@link OutputStream}
  */
-public interface Streamable {
+public interface Streamable extends Serializable {
     void write(OutputStream stream) throws IOException;
+
+    void write(ByteBuffer buffer);
 }

core/src/main/java/ch/dissem/bitmessage/entity/VerAck.java

@@ -18,11 +18,14 @@ package ch.dissem.bitmessage.entity;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 
 /**
  * The 'verack' command answers a 'version' command, accepting the other node's version.
  */
 public class VerAck implements MessagePayload {
+    private static final long serialVersionUID = -4302074845199181687L;
+
     @Override
     public Command getCommand() {
         return Command.VERACK;
@@ -32,4 +35,9 @@ public class VerAck implements MessagePayload {
     public void write(OutputStream stream) throws IOException {
         // 'verack' doesn't have any payload, so there is nothing to write
     }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        // 'verack' doesn't have any payload, so there is nothing to write
+    }
 }

core/src/main/java/ch/dissem/bitmessage/entity/Version.java

@@ -23,12 +23,14 @@ import ch.dissem.bitmessage.utils.UnixTime;
 
 import java.io.IOException;
 import java.io.OutputStream;
-import java.util.Random;
+import java.nio.ByteBuffer;
 
 /**
  * The 'version' command advertises this node's latest supported protocol version upon initiation.
  */
 public class Version implements MessagePayload {
+    private static final long serialVersionUID = 7219240857343176567L;
+
     /**
      * Identifies protocol version being used by the node. Should equal 3. Nodes should disconnect if the remote node's
      * version is lower but continue with the connection if it is higher.
@@ -132,6 +134,18 @@ public class Version implements MessagePayload {
         Encode.varIntList(streams, stream);
     }
 
+    @Override
+    public void write(ByteBuffer buffer) {
+        Encode.int32(version, buffer);
+        Encode.int64(services, buffer);
+        Encode.int64(timestamp, buffer);
+        addrRecv.write(buffer, true);
+        addrFrom.write(buffer, true);
+        Encode.int64(nonce, buffer);
+        Encode.varString(userAgent, buffer);
+        Encode.varIntList(streams, buffer);
+    }
+
 
     public static final class Builder {
         private int version;
@@ -143,16 +157,13 @@ public class Version implements MessagePayload {
         private String userAgent;
         private long[] streamNumbers;
 
-        public Builder() {
-        }
-
-        public Builder defaults() {
+        public Builder defaults(long clientNonce) {
             version = BitmessageContext.CURRENT_VERSION;
             services = 1;
             timestamp = UnixTime.now();
-            nonce = new Random().nextInt();
             userAgent = "/Jabit:0.0.1/";
             streamNumbers = new long[]{1};
+            nonce = clientNonce;
             return this;
         }
 

core/src/main/java/ch/dissem/bitmessage/entity/payload/Broadcast.java

@@ -21,17 +21,20 @@ import ch.dissem.bitmessage.entity.Encrypted;
 import ch.dissem.bitmessage.entity.Plaintext;
 import ch.dissem.bitmessage.entity.PlaintextHolder;
 import ch.dissem.bitmessage.exception.DecryptionFailedException;
-import ch.dissem.bitmessage.utils.Security;
 
 import java.io.IOException;
+import java.util.Objects;
 
 import static ch.dissem.bitmessage.entity.Plaintext.Type.BROADCAST;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 
 /**
  * Users who are subscribed to the sending address will see the message appear in their inbox.
  * Broadcasts are version 4 or 5.
  */
 public abstract class Broadcast extends ObjectPayload implements Encrypted, PlaintextHolder {
+    private static final long serialVersionUID = 4064521827582239069L;
+
     protected final long stream;
     protected CryptoBox encrypted;
     protected Plaintext plaintext;
@@ -78,7 +81,7 @@ public abstract class Broadcast extends ObjectPayload implements Encrypted, Plai
     }
 
     public void encrypt() throws IOException {
-        encrypt(Security.createPublicKey(plaintext.getFrom().getPublicDecryptionKey()).getEncoded(false));
+        encrypt(cryptography().createPublicKey(plaintext.getFrom().getPublicDecryptionKey()));
     }
 
     @Override
@@ -94,4 +97,18 @@ public abstract class Broadcast extends ObjectPayload implements Encrypted, Plai
     public boolean isDecrypted() {
         return plaintext != null;
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Broadcast broadcast = (Broadcast) o;
+        return stream == broadcast.stream &&
+                (Objects.equals(encrypted, broadcast.encrypted) || Objects.equals(plaintext, broadcast.plaintext));
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(stream);
+    }
 }

core/src/main/java/ch/dissem/bitmessage/entity/payload/CryptoBox.java

@@ -17,64 +17,56 @@
 package ch.dissem.bitmessage.entity.payload;
 
 import ch.dissem.bitmessage.entity.Streamable;
-import ch.dissem.bitmessage.entity.valueobject.PrivateKey;
+import ch.dissem.bitmessage.exception.ApplicationException;
 import ch.dissem.bitmessage.exception.DecryptionFailedException;
 import ch.dissem.bitmessage.utils.*;
-import org.bouncycastle.crypto.BufferedBlockCipher;
-import org.bouncycastle.crypto.CipherParameters;
-import org.bouncycastle.crypto.InvalidCipherTextException;
-import org.bouncycastle.crypto.engines.AESEngine;
-import org.bouncycastle.crypto.modes.CBCBlockCipher;
-import org.bouncycastle.crypto.paddings.PKCS7Padding;
-import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
-import org.bouncycastle.crypto.params.KeyParameter;
-import org.bouncycastle.crypto.params.ParametersWithIV;
-import org.bouncycastle.math.ec.ECFieldElement;
-import org.bouncycastle.math.ec.ECPoint;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.*;
-import java.math.BigInteger;
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 
 import static ch.dissem.bitmessage.entity.valueobject.PrivateKey.PRIVATE_KEY_SIZE;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 
 
 public class CryptoBox implements Streamable {
+    private static final long serialVersionUID = 7217659539975573852L;
     private static final Logger LOG = LoggerFactory.getLogger(CryptoBox.class);
 
     private final byte[] initializationVector;
     private final int curveType;
-    private final ECPoint R;
+    private final byte[] R;
     private final byte[] mac;
     private byte[] encrypted;
 
-    public CryptoBox(Streamable data, byte[] encryptionKey) throws IOException {
-        this(data, Security.keyToPoint(encryptionKey));
+
+    public CryptoBox(Streamable data, byte[] K) throws IOException {
+        this(Encode.bytes(data), K);
     }
 
-    public CryptoBox(Streamable data, ECPoint K) throws IOException {
+    public CryptoBox(byte[] data, byte[] K) throws IOException {
         curveType = 0x02CA;
 
         // 1. The destination public key is called K.
         // 2. Generate 16 random bytes using a secure random number generator. Call them IV.
-        initializationVector = Security.randomBytes(16);
+        initializationVector = cryptography().randomBytes(16);
 
         // 3. Generate a new random EC key pair with private key called r and public key called R.
-        byte[] r = Security.randomBytes(PRIVATE_KEY_SIZE);
-        R = Security.createPublicKey(r);
+        byte[] r = cryptography().randomBytes(PRIVATE_KEY_SIZE);
+        R = cryptography().createPublicKey(r);
         // 4. Do an EC point multiply with public key K and private key r. This gives you public key P.
-        ECPoint P = K.multiply(Security.keyToBigInt(r)).normalize();
-        byte[] X = P.getXCoord().getEncoded();
+        byte[] P = cryptography().multiply(K, r);
+        byte[] X = Points.getX(P);
         // 5. Use the X component of public key P and calculate the SHA512 hash H.
-        byte[] H = Security.sha512(X);
+        byte[] H = cryptography().sha512(X);
         // 6. The first 32 bytes of H are called key_e and the last 32 bytes are called key_m.
         byte[] key_e = Arrays.copyOfRange(H, 0, 32);
         byte[] key_m = Arrays.copyOfRange(H, 32, 64);
         // 7. Pad the input text to a multiple of 16 bytes, in accordance to PKCS7.
         // 8. Encrypt the data with AES-256-CBC, using IV as initialization vector, key_e as encryption key and the padded input text as payload. Call the output cipher text.
-        encrypted = crypt(true, Encode.bytes(data), key_e);
+        encrypted = cryptography().crypt(true, data, key_e, initializationVector);
         // 9. Calculate a 32 byte MAC with HMACSHA256, using key_m as salt and IV + R + cipher text as data. Call the output MAC.
         mac = calculateMac(key_m);
 
@@ -84,7 +76,7 @@ public class CryptoBox implements Streamable {
     private CryptoBox(Builder builder) {
         initializationVector = builder.initializationVector;
         curveType = builder.curveType;
-        R = Security.createPoint(builder.xComponent, builder.yComponent);
+        R = cryptography().createPoint(builder.xComponent, builder.yComponent);
         encrypted = builder.encrypted;
         mac = builder.mac;
     }
@@ -102,18 +94,17 @@ public class CryptoBox implements Streamable {
     }
 
     /**
-     * @param privateKey a private key, typically should be 32 bytes long
+     * @param k a private key, typically should be 32 bytes long
      * @return an InputStream yielding the decrypted data
      * @throws DecryptionFailedException if the payload can't be decrypted using this private key
      * @see <a href='https://bitmessage.org/wiki/Encryption#Decryption'>https://bitmessage.org/wiki/Encryption#Decryption</a>
      */
-    public InputStream decrypt(byte[] privateKey) throws DecryptionFailedException {
+    public InputStream decrypt(byte[] k) throws DecryptionFailedException {
         // 1. The private key used to decrypt is called k.
-        BigInteger k = Security.keyToBigInt(privateKey);
         // 2. Do an EC point multiply with private key k and public key R. This gives you public key P.
-        ECPoint P = R.multiply(k).normalize();
+        byte[] P = cryptography().multiply(R, k);
         // 3. Use the X component of public key P and calculate the SHA512 hash H.
-        byte[] H = Security.sha512(P.getXCoord().getEncoded());
+        byte[] H = cryptography().sha512(Arrays.copyOfRange(P, 1, 33));
         // 4. The first 32 bytes of H are called key_e and the last 32 bytes are called key_m.
         byte[] key_e = Arrays.copyOfRange(H, 0, 32);
         byte[] key_m = Arrays.copyOfRange(H, 32, 64);
@@ -126,61 +117,57 @@ public class CryptoBox implements Streamable {
 
         // 7. Decrypt the cipher text with AES-256-CBC, using IV as initialization vector, key_e as decryption key
         //    and the cipher text as payload. The output is the padded input text.
-        return new ByteArrayInputStream(crypt(false, encrypted, key_e));
+        return new ByteArrayInputStream(cryptography().crypt(false, encrypted, key_e, initializationVector));
     }
 
     private byte[] calculateMac(byte[] key_m) {
         try {
             ByteArrayOutputStream macData = new ByteArrayOutputStream();
             writeWithoutMAC(macData);
-            return Security.mac(key_m, macData.toByteArray());
+            return cryptography().mac(key_m, macData.toByteArray());
         } catch (IOException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
-    private byte[] crypt(boolean encrypt, byte[] data, byte[] key_e) {
-        BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new AESEngine()), new PKCS7Padding());
-
-        CipherParameters params = new ParametersWithIV(new KeyParameter(key_e), initializationVector);
-
-        cipher.init(encrypt, params);
-
-        byte[] buffer = new byte[cipher.getOutputSize(data.length)];
-        int length = cipher.processBytes(data, 0, data.length, buffer, 0);
-        try {
-            length += cipher.doFinal(buffer, length);
-        } catch (InvalidCipherTextException e) {
-            throw new IllegalArgumentException(e);
-        }
-        if (length < buffer.length) {
-            return Arrays.copyOfRange(buffer, 0, length);
-        }
-        return buffer;
-    }
-
     private void writeWithoutMAC(OutputStream out) throws IOException {
         out.write(initializationVector);
         Encode.int16(curveType, out);
-        writeCoordinateComponent(out, R.getXCoord());
-        writeCoordinateComponent(out, R.getYCoord());
+        writeCoordinateComponent(out, Points.getX(R));
+        writeCoordinateComponent(out, Points.getY(R));
         out.write(encrypted);
     }
 
-    private void writeCoordinateComponent(OutputStream out, ECFieldElement coord) throws IOException {
-        byte[] x = coord.getEncoded();
+    private void writeCoordinateComponent(OutputStream out, byte[] x) throws IOException {
         int offset = Bytes.numberOfLeadingZeros(x);
         int length = x.length - offset;
         Encode.int16(length, out);
         out.write(x, offset, length);
     }
 
+    private void writeCoordinateComponent(ByteBuffer buffer, byte[] x) {
+        int offset = Bytes.numberOfLeadingZeros(x);
+        int length = x.length - offset;
+        Encode.int16(length, buffer);
+        buffer.put(x, offset, length);
+    }
+
     @Override
     public void write(OutputStream stream) throws IOException {
         writeWithoutMAC(stream);
         stream.write(mac);
     }
 
+    @Override
+    public void write(ByteBuffer buffer) {
+        buffer.put(initializationVector);
+        Encode.int16(curveType, buffer);
+        writeCoordinateComponent(buffer, Points.getX(R));
+        writeCoordinateComponent(buffer, Points.getY(R));
+        buffer.put(encrypted);
+        buffer.put(mac);
+    }
+
     public static final class Builder {
         private byte[] initializationVector;
         private int curveType;
@@ -195,7 +182,7 @@ public class CryptoBox implements Streamable {
         }
 
         public Builder curveType(int curveType) {
-            if (curveType != 0x2CA) LOG.debug("Unexpected curve type " + curveType);
+            if (curveType != 0x2CA) LOG.trace("Unexpected curve type " + curveType);
             this.curveType = curveType;
             return this;
         }

core/src/main/java/ch/dissem/bitmessage/entity/payload/GenericPayload.java

@@ -21,6 +21,7 @@ import ch.dissem.bitmessage.utils.Decode;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 
 /**
@@ -28,6 +29,8 @@ import java.util.Arrays;
  * have to know what it is.
  */
 public class GenericPayload extends ObjectPayload {
+    private static final long serialVersionUID = -912314085064185940L;
+
     private long stream;
     private byte[] data;
 
@@ -37,7 +40,7 @@ public class GenericPayload extends ObjectPayload {
         this.data = data;
     }
 
-    public static GenericPayload read(long version, InputStream is, long stream, int length) throws IOException {
+    public static GenericPayload read(long version, long stream, InputStream is, int length) throws IOException {
         return new GenericPayload(version, stream, Decode.bytes(is, length));
     }
 
@@ -51,11 +54,20 @@ public class GenericPayload extends ObjectPayload {
         return stream;
     }
 
+    public byte[] getData() {
+        return data;
+    }
+
     @Override
     public void write(OutputStream stream) throws IOException {
         stream.write(data);
     }
 
+    @Override
+    public void write(ByteBuffer buffer) {
+        buffer.put(data);
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;

core/src/main/java/ch/dissem/bitmessage/entity/payload/GetPubkey.java

@@ -22,11 +22,14 @@ import ch.dissem.bitmessage.utils.Decode;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 
 /**
  * Request for a public key.
  */
 public class GetPubkey extends ObjectPayload {
+    private static final long serialVersionUID = -3634516646972610180L;
+
     private long stream;
     private byte[] ripeTag;
 
@@ -71,4 +74,9 @@ public class GetPubkey extends ObjectPayload {
     public void write(OutputStream stream) throws IOException {
         stream.write(ripeTag);
     }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        buffer.put(ripeTag);
+    }
 }

core/src/main/java/ch/dissem/bitmessage/entity/payload/Msg.java

@@ -24,6 +24,8 @@ import ch.dissem.bitmessage.exception.DecryptionFailedException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.util.Objects;
 
 import static ch.dissem.bitmessage.entity.Plaintext.Type.MSG;
 
@@ -31,6 +33,9 @@ import static ch.dissem.bitmessage.entity.Plaintext.Type.MSG;
  * Used for person-to-person messages.
  */
 public class Msg extends ObjectPayload implements Encrypted, PlaintextHolder {
+    private static final long serialVersionUID = 4327495048296365733L;
+    public static final int ACK_LENGTH = 32;
+
     private long stream;
     private CryptoBox encrypted;
     private Plaintext plaintext;
@@ -106,4 +111,25 @@ public class Msg extends ObjectPayload implements Encrypted, PlaintextHolder {
         if (encrypted == null) throw new IllegalStateException("Msg must be signed and encrypted before writing it.");
         encrypted.write(out);
     }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        if (encrypted == null) throw new IllegalStateException("Msg must be signed and encrypted before writing it.");
+        encrypted.write(buffer);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        if (!super.equals(o)) return false;
+        Msg msg = (Msg) o;
+        return stream == msg.stream &&
+                (Objects.equals(encrypted, msg.encrypted) || Objects.equals(plaintext, msg.plaintext));
+    }
+
+    @Override
+    public int hashCode() {
+        return (int) stream;
+    }
 }

core/src/main/java/ch/dissem/bitmessage/entity/payload/ObjectPayload.java

@@ -26,6 +26,8 @@ import java.io.OutputStream;
  * The payload of an 'object' command. This is shared by the network.
  */
 public abstract class ObjectPayload implements Streamable {
+    private static final long serialVersionUID = -5034977402902364482L;
+
     private final long version;
 
     protected ObjectPayload(long version) {

core/src/main/java/ch/dissem/bitmessage/entity/payload/Pubkey.java

@@ -18,15 +18,17 @@ package ch.dissem.bitmessage.entity.payload;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 import java.util.ArrayList;
 
-import static ch.dissem.bitmessage.utils.Security.ripemd160;
-import static ch.dissem.bitmessage.utils.Security.sha512;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 
 /**
  * Public keys for signing and encryption, the answer to a 'getpubkey' request.
  */
 public abstract class Pubkey extends ObjectPayload {
+    private static final long serialVersionUID = -6634533361454999619L;
+
     public final static long LATEST_VERSION = 4;
 
     protected Pubkey(long version) {
@@ -34,7 +36,7 @@ public abstract class Pubkey extends ObjectPayload {
     }
 
     public static byte[] getRipe(byte[] publicSigningKey, byte[] publicEncryptionKey) {
-        return ripemd160(sha512(publicSigningKey, publicEncryptionKey));
+        return cryptography().ripemd160(cryptography().sha512(publicSigningKey, publicEncryptionKey));
     }
 
     public abstract byte[] getSigningKey();
@@ -44,7 +46,7 @@ public abstract class Pubkey extends ObjectPayload {
     public abstract int getBehaviorBitfield();
 
     public byte[] getRipe() {
-        return ripemd160(sha512(getSigningKey(), getEncryptionKey()));
+        return cryptography().ripemd160(cryptography().sha512(getSigningKey(), getEncryptionKey()));
     }
 
     public long getNonceTrialsPerByte() {
@@ -59,6 +61,10 @@ public abstract class Pubkey extends ObjectPayload {
         write(out);
     }
 
+    public void writeUnencrypted(ByteBuffer buffer){
+        write(buffer);
+    }
+
     protected byte[] add0x04(byte[] key) {
         if (key.length == 65) return key;
         byte[] result = new byte[65];
@@ -75,16 +81,19 @@ public abstract class Pubkey extends ObjectPayload {
          * Receiving node expects that the RIPE hash encoded in their address preceedes the encrypted message data of msg
          * messages bound for them.
          */
-        INCLUDE_DESTINATION(1 << 30),
+        INCLUDE_DESTINATION(30),
         /**
          * If true, the receiving node does send acknowledgements (rather than dropping them).
          */
-        DOES_ACK(1 << 31);
+        DOES_ACK(31);
 
         private int bit;
 
-        Feature(int bit) {
-            this.bit = bit;
+        Feature(int bitNumber) {
+            // The Bitmessage Protocol Specification starts counting at the most significant bit,
+            // thus the slightly awkward calculation.
+            // https://bitmessage.org/wiki/Protocol_specification#Pubkey_bitfield_features
+            this.bit = 1 << (31 - bitNumber);
         }
 
         public static int bitfield(Feature... features) {
@@ -104,5 +113,9 @@ public abstract class Pubkey extends ObjectPayload {
             }
             return features.toArray(new Feature[features.size()]);
         }
+
+        public boolean isActive(int bitfield) {
+            return (bitfield & bit) != 0;
+        }
     }
 }

core/src/main/java/ch/dissem/bitmessage/entity/payload/V2Pubkey.java

@@ -22,11 +22,14 @@ import ch.dissem.bitmessage.utils.Encode;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 
 /**
  * A version 2 public key.
  */
 public class V2Pubkey extends Pubkey {
+    private static final long serialVersionUID = -257598690676510460L;
+
     protected long stream;
     protected int behaviorBitfield;
     protected byte[] publicSigningKey; // 64 Bytes
@@ -84,10 +87,17 @@ public class V2Pubkey extends Pubkey {
     }
 
     @Override
-    public void write(OutputStream os) throws IOException {
-        Encode.int32(behaviorBitfield, os);
-        os.write(publicSigningKey, 1, 64);
-        os.write(publicEncryptionKey, 1, 64);
+    public void write(OutputStream out) throws IOException {
+        Encode.int32(behaviorBitfield, out);
+        out.write(publicSigningKey, 1, 64);
+        out.write(publicEncryptionKey, 1, 64);
+    }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        Encode.int32(behaviorBitfield, buffer);
+        buffer.put(publicSigningKey, 1, 64);
+        buffer.put(publicEncryptionKey, 1, 64);
     }
 
     public static class Builder {
@@ -96,9 +106,6 @@ public class V2Pubkey extends Pubkey {
         private byte[] publicSigningKey;
         private byte[] publicEncryptionKey;
 
-        public Builder() {
-        }
-
         public Builder stream(long streamNumber) {
             this.streamNumber = streamNumber;
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/payload/V3Pubkey.java

@@ -29,6 +29,8 @@ import java.util.Objects;
  * A version 3 public key.
  */
 public class V3Pubkey extends V2Pubkey {
+    private static final long serialVersionUID = 6958853116648528319L;
+
     long nonceTrialsPerByte;
     long extraBytes;
     byte[] signature;
@@ -123,9 +125,6 @@ public class V3Pubkey extends V2Pubkey {
         private long extraBytes;
         private byte[] signature = new byte[0];
 
-        public Builder() {
-        }
-
         public Builder stream(long streamNumber) {
             this.streamNumber = streamNumber;
             return this;

core/src/main/java/ch/dissem/bitmessage/entity/payload/V4Broadcast.java

@@ -22,12 +22,15 @@ import ch.dissem.bitmessage.entity.Plaintext;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 
 /**
  * Users who are subscribed to the sending address will see the message appear in their inbox.
  * Broadcasts are version 4 or 5.
  */
 public class V4Broadcast extends Broadcast {
+    private static final long serialVersionUID = 195663108282762711L;
+
     protected V4Broadcast(long version, long stream, CryptoBox encrypted, Plaintext plaintext) {
         super(version, stream, encrypted, plaintext);
     }
@@ -56,4 +59,9 @@ public class V4Broadcast extends Broadcast {
     public void write(OutputStream out) throws IOException {
         encrypted.write(out);
     }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        encrypted.write(buffer);
+    }
 }

core/src/main/java/ch/dissem/bitmessage/entity/payload/V4Pubkey.java

@@ -24,6 +24,7 @@ import ch.dissem.bitmessage.utils.Decode;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 
 /**
@@ -33,6 +34,8 @@ import java.util.Arrays;
  * to create messages to be used in spam or in flooding attacks.
  */
 public class V4Pubkey extends Pubkey implements Encrypted {
+    private static final long serialVersionUID = 1556710353694033093L;
+
     private long stream;
     private byte[] tag;
     private CryptoBox encrypted;
@@ -83,11 +86,22 @@ public class V4Pubkey extends Pubkey implements Encrypted {
         encrypted.write(stream);
     }
 
+    @Override
+    public void write(ByteBuffer buffer) {
+        buffer.put(tag);
+        encrypted.write(buffer);
+    }
+
     @Override
     public void writeUnencrypted(OutputStream out) throws IOException {
         decrypted.write(out);
     }
 
+    @Override
+    public void writeUnencrypted(ByteBuffer buffer) {
+        decrypted.write(buffer);
+    }
+
     @Override
     public void writeBytesToSign(OutputStream out) throws IOException {
         out.write(tag);

core/src/main/java/ch/dissem/bitmessage/entity/payload/V5Broadcast.java

@@ -28,6 +28,8 @@ import java.io.OutputStream;
  * Users who are subscribed to the sending address will see the message appear in their inbox.
  */
 public class V5Broadcast extends V4Broadcast {
+    private static final long serialVersionUID = 920649721626968644L;
+
     private byte[] tag;
 
     private V5Broadcast(long stream, byte[] tag, CryptoBox encrypted) {

core/src/main/java/ch/dissem/bitmessage/entity/valueobject/InventoryVector.java

@@ -21,9 +21,13 @@ import ch.dissem.bitmessage.utils.Strings;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.Serializable;
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 
-public class InventoryVector implements Streamable {
+public class InventoryVector implements Streamable, Serializable {
+    private static final long serialVersionUID = -7349009673063348719L;
+
     /**
      * Hash of the object
      */
@@ -37,12 +41,11 @@ public class InventoryVector implements Streamable {
         InventoryVector that = (InventoryVector) o;
 
         return Arrays.equals(hash, that.hash);
-
     }
 
     @Override
     public int hashCode() {
-        return hash != null ? Arrays.hashCode(hash) : 0;
+        return hash == null ? 0 : Arrays.hashCode(hash);
     }
 
     public byte[] getHash() {
@@ -54,8 +57,13 @@ public class InventoryVector implements Streamable {
     }
 
     @Override
-    public void write(OutputStream stream) throws IOException {
-        stream.write(hash);
+    public void write(OutputStream out) throws IOException {
+        out.write(hash);
+    }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        buffer.put(hash);
     }
 
     @Override

core/src/main/java/ch/dissem/bitmessage/entity/valueobject/Label.java

@@ -16,9 +16,12 @@
 
 package ch.dissem.bitmessage.entity.valueobject;
 
+import java.io.Serializable;
 import java.util.Objects;
 
-public class Label {
+public class Label implements Serializable {
+    private static final long serialVersionUID = 831782893630994914L;
+
     private Object id;
     private String label;
     private Type type;
@@ -78,6 +81,7 @@ public class Label {
         INBOX,
         BROADCAST,
         DRAFT,
+        OUTBOX,
         SENT,
         UNREAD,
         TRASH

core/src/main/java/ch/dissem/bitmessage/entity/valueobject/NetworkAddress.java

@@ -17,37 +17,43 @@
 package ch.dissem.bitmessage.entity.valueobject;
 
 import ch.dissem.bitmessage.entity.Streamable;
+import ch.dissem.bitmessage.exception.ApplicationException;
 import ch.dissem.bitmessage.utils.Encode;
 import ch.dissem.bitmessage.utils.UnixTime;
 
 import java.io.IOException;
 import java.io.OutputStream;
 import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.SocketAddress;
 import java.net.UnknownHostException;
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 
 /**
  * A node's address. It's written in IPv6 format.
  */
 public class NetworkAddress implements Streamable {
+    private static final long serialVersionUID = 2500120578167100300L;
+
     private long time;
 
     /**
      * Stream number for this node
      */
-    private long stream;
+    private final long stream;
 
     /**
      * same service(s) listed in version
      */
-    private long services;
+    private final long services;
 
     /**
      * IPv6 address. IPv4 addresses are written into the message as a 16 byte IPv4-mapped IPv6 address
      * (12 bytes 00 00 00 00 00 00 00 00 00 00 FF FF, followed by the 4 bytes of the IPv4 address).
      */
-    private byte[] ipv6;
-    private int port;
+    private final byte[] ipv6;
+    private final int port;
 
     private NetworkAddress(Builder builder) {
         time = builder.time;
@@ -85,7 +91,7 @@ public class NetworkAddress implements Streamable {
         try {
             return InetAddress.getByAddress(ipv6);
         } catch (UnknownHostException e) {
-            throw new RuntimeException(e);
+            throw new ApplicationException(e);
         }
     }
 
@@ -116,14 +122,29 @@ public class NetworkAddress implements Streamable {
         write(stream, false);
     }
 
-    public void write(OutputStream stream, boolean light) throws IOException {
+    public void write(OutputStream out, boolean light) throws IOException {
         if (!light) {
-            Encode.int64(time, stream);
-            Encode.int32(this.stream, stream);
+            Encode.int64(time, out);
+            Encode.int32(stream, out);
         }
-        Encode.int64(services, stream);
-        stream.write(ipv6);
-        Encode.int16(port, stream);
+        Encode.int64(services, out);
+        out.write(ipv6);
+        Encode.int16(port, out);
+    }
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        write(buffer, false);
+    }
+
+    public void write(ByteBuffer buffer, boolean light) {
+        if (!light) {
+            Encode.int64(time, buffer);
+            Encode.int32(stream, buffer);
+        }
+        Encode.int64(services, buffer);
+        buffer.put(ipv6);
+        Encode.int16(port, buffer);
     }
 
     public static final class Builder {
@@ -133,9 +154,6 @@ public class NetworkAddress implements Streamable {
         private byte[] ipv6;
         private int port;
 
-        public Builder() {
-        }
-
         public Builder time(final long time) {
             this.time = time;
             return this;
@@ -199,6 +217,17 @@ public class NetworkAddress implements Streamable {
             return this;
         }
 
+        public Builder address(SocketAddress address) {
+            if (address instanceof InetSocketAddress) {
+                InetSocketAddress inetAddress = (InetSocketAddress) address;
+                ip(inetAddress.getAddress());
+                port(inetAddress.getPort());
+            } else {
+                throw new IllegalArgumentException("Unknown type of address: " + address.getClass());
+            }
+            return this;
+        }
+
         public NetworkAddress build() {
             if (time == 0) {
                 time = UnixTime.now();

core/src/main/java/ch/dissem/bitmessage/entity/valueobject/PrivateKey.java

@@ -0,0 +1,198 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.entity.valueobject;
+
+import ch.dissem.bitmessage.InternalContext;
+import ch.dissem.bitmessage.entity.BitmessageAddress;
+import ch.dissem.bitmessage.entity.Streamable;
+import ch.dissem.bitmessage.entity.payload.Pubkey;
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.factory.Factory;
+import ch.dissem.bitmessage.utils.Bytes;
+import ch.dissem.bitmessage.utils.Decode;
+import ch.dissem.bitmessage.utils.Encode;
+
+import java.io.*;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
+
+/**
+ * Represents a private key. Additional information (stream, version, features, ...) is stored in the accompanying
+ * {@link Pubkey} object.
+ */
+public class PrivateKey implements Streamable {
+    private static final long serialVersionUID = 8562555470709110558L;
+
+    public static final int PRIVATE_KEY_SIZE = 32;
+
+    private final byte[] privateSigningKey;
+    private final byte[] privateEncryptionKey;
+
+    private final Pubkey pubkey;
+
+    public PrivateKey(boolean shorter, long stream, long nonceTrialsPerByte, long extraBytes, Pubkey.Feature... features) {
+        byte[] privSK;
+        byte[] pubSK;
+        byte[] privEK;
+        byte[] pubEK;
+        byte[] ripe;
+        do {
+            privSK = cryptography().randomBytes(PRIVATE_KEY_SIZE);
+            privEK = cryptography().randomBytes(PRIVATE_KEY_SIZE);
+            pubSK = cryptography().createPublicKey(privSK);
+            pubEK = cryptography().createPublicKey(privEK);
+            ripe = Pubkey.getRipe(pubSK, pubEK);
+        } while (ripe[0] != 0 || (shorter && ripe[1] != 0));
+        this.privateSigningKey = privSK;
+        this.privateEncryptionKey = privEK;
+        this.pubkey = cryptography().createPubkey(Pubkey.LATEST_VERSION, stream, privateSigningKey, privateEncryptionKey,
+                nonceTrialsPerByte, extraBytes, features);
+    }
+
+    public PrivateKey(byte[] privateSigningKey, byte[] privateEncryptionKey, Pubkey pubkey) {
+        this.privateSigningKey = privateSigningKey;
+        this.privateEncryptionKey = privateEncryptionKey;
+        this.pubkey = pubkey;
+    }
+
+    public PrivateKey(BitmessageAddress address, String passphrase) {
+        this(address.getVersion(), address.getStream(), passphrase);
+    }
+
+    public PrivateKey(long version, long stream, String passphrase) {
+        this(new Builder(version, stream, false).seed(passphrase).generate());
+    }
+
+    private PrivateKey(Builder builder) {
+        this.privateSigningKey = builder.privSK;
+        this.privateEncryptionKey = builder.privEK;
+        this.pubkey = Factory.createPubkey(builder.version, builder.stream, builder.pubSK, builder.pubEK,
+                InternalContext.NETWORK_NONCE_TRIALS_PER_BYTE, InternalContext.NETWORK_EXTRA_BYTES);
+    }
+
+    private static class Builder {
+        final long version;
+        final long stream;
+        final boolean shorter;
+
+        byte[] seed;
+        long nextNonce;
+
+        byte[] privSK, privEK;
+        byte[] pubSK, pubEK;
+
+        private Builder(long version, long stream, boolean shorter) {
+            this.version = version;
+            this.stream = stream;
+            this.shorter = shorter;
+        }
+
+        Builder seed(String passphrase) {
+            try {
+                seed = passphrase.getBytes("UTF-8");
+            } catch (UnsupportedEncodingException e) {
+                throw new ApplicationException(e);
+            }
+            return this;
+        }
+
+        Builder generate() {
+            long signingKeyNonce = nextNonce;
+            long encryptionKeyNonce = nextNonce + 1;
+            byte[] ripe;
+            do {
+                privEK = Bytes.truncate(cryptography().sha512(seed, Encode.varInt(encryptionKeyNonce)), 32);
+                privSK = Bytes.truncate(cryptography().sha512(seed, Encode.varInt(signingKeyNonce)), 32);
+                pubSK = cryptography().createPublicKey(privSK);
+                pubEK = cryptography().createPublicKey(privEK);
+                ripe = cryptography().ripemd160(cryptography().sha512(pubSK, pubEK));
+
+                signingKeyNonce += 2;
+                encryptionKeyNonce += 2;
+            } while (ripe[0] != 0 || (shorter && ripe[1] != 0));
+            nextNonce = signingKeyNonce;
+            return this;
+        }
+    }
+
+    public static List<PrivateKey> deterministic(String passphrase, int numberOfAddresses, long version, long stream, boolean shorter) {
+        List<PrivateKey> result = new ArrayList<>(numberOfAddresses);
+        Builder builder = new Builder(version, stream, shorter).seed(passphrase);
+        for (int i = 0; i < numberOfAddresses; i++) {
+            builder.generate();
+            result.add(new PrivateKey(builder));
+        }
+        return result;
+    }
+
+    public static PrivateKey read(InputStream is) throws IOException {
+        int version = (int) Decode.varInt(is);
+        long stream = Decode.varInt(is);
+        int len = (int) Decode.varInt(is);
+        Pubkey pubkey = Factory.readPubkey(version, stream, is, len, false);
+        len = (int) Decode.varInt(is);
+        byte[] signingKey = Decode.bytes(is, len);
+        len = (int) Decode.varInt(is);
+        byte[] encryptionKey = Decode.bytes(is, len);
+        return new PrivateKey(signingKey, encryptionKey, pubkey);
+    }
+
+    public byte[] getPrivateSigningKey() {
+        return privateSigningKey;
+    }
+
+    public byte[] getPrivateEncryptionKey() {
+        return privateEncryptionKey;
+    }
+
+    public Pubkey getPubkey() {
+        return pubkey;
+    }
+
+    @Override
+    public void write(OutputStream out) throws IOException {
+        Encode.varInt(pubkey.getVersion(), out);
+        Encode.varInt(pubkey.getStream(), out);
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        pubkey.writeUnencrypted(baos);
+        Encode.varInt(baos.size(), out);
+        out.write(baos.toByteArray());
+        Encode.varInt(privateSigningKey.length, out);
+        out.write(privateSigningKey);
+        Encode.varInt(privateEncryptionKey.length, out);
+        out.write(privateEncryptionKey);
+    }
+
+
+    @Override
+    public void write(ByteBuffer buffer) {
+        Encode.varInt(pubkey.getVersion(), buffer);
+        Encode.varInt(pubkey.getStream(), buffer);
+        try {
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            pubkey.writeUnencrypted(baos);
+            Encode.varBytes(baos.toByteArray(), buffer);
+        } catch (IOException e) {
+            throw new ApplicationException(e);
+        }
+        Encode.varBytes(privateSigningKey, buffer);
+        Encode.varBytes(privateEncryptionKey, buffer);
+    }
+}

core/src/main/java/ch/dissem/bitmessage/exception/AddressFormatException.java

@@ -20,6 +20,8 @@ package ch.dissem.bitmessage.exception;
  * Indicates an illegal Bitmessage address
  */
 public class AddressFormatException extends RuntimeException {
+    private static final long serialVersionUID = 6943764578672021573L;
+
     public AddressFormatException(String message) {
         super(message);
     }

core/src/main/java/ch/dissem/bitmessage/exception/ApplicationException.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.exception;
+
+/**
+ * @author Christian Basler
+ */
+public class ApplicationException extends RuntimeException {
+    private static final long serialVersionUID = 1796776684126759324L;
+
+    public ApplicationException(Throwable cause) {
+        super(cause);
+    }
+
+    public ApplicationException(String message) {
+        super(message);
+    }
+}

core/src/main/java/ch/dissem/bitmessage/exception/DecryptionFailedException.java

@@ -17,4 +17,5 @@
 package ch.dissem.bitmessage.exception;
 
 public class DecryptionFailedException extends Exception {
+    private static final long serialVersionUID = 3241116253113872731L;
 }

core/src/main/java/ch/dissem/bitmessage/exception/InsufficientProofOfWorkException.java

@@ -22,6 +22,8 @@ import java.io.IOException;
 import java.util.Arrays;
 
 public class InsufficientProofOfWorkException extends IOException {
+    private static final long serialVersionUID = 9105580366564571318L;
+
     public InsufficientProofOfWorkException(byte[] target, byte[] hash) {
         super("Insufficient proof of work: " + Strings.hex(target) + " required, " + Strings.hex(Arrays.copyOfRange(hash, 0, 8)) + " achieved.");
     }

core/src/main/java/ch/dissem/bitmessage/exception/NodeException.java

@@ -22,6 +22,8 @@ package ch.dissem.bitmessage.exception;
  * @author Ch. Basler
  */
 public class NodeException extends RuntimeException {
+    private static final long serialVersionUID = 2965325796118227802L;
+
     public NodeException(String message) {
         super(message);
     }

core/src/main/java/ch/dissem/bitmessage/factory/BufferPool.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.factory;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.nio.ByteBuffer;
+import java.util.Map;
+import java.util.Stack;
+import java.util.TreeMap;
+
+import static ch.dissem.bitmessage.ports.NetworkHandler.HEADER_SIZE;
+import static ch.dissem.bitmessage.ports.NetworkHandler.MAX_PAYLOAD_SIZE;
+
+/**
+ * A pool for {@link ByteBuffer}s. As they may use up a lot of memory,
+ * they should be reused as efficiently as possible.
+ */
+class BufferPool {
+    private static final Logger LOG = LoggerFactory.getLogger(BufferPool.class);
+
+    public static final BufferPool bufferPool = new BufferPool();
+
+    private final Map<Integer, Stack<ByteBuffer>> pools = new TreeMap<>();
+
+    private BufferPool() {
+        pools.put(HEADER_SIZE, new Stack<ByteBuffer>());
+        pools.put(54, new Stack<ByteBuffer>());
+        pools.put(1000, new Stack<ByteBuffer>());
+        pools.put(60000, new Stack<ByteBuffer>());
+        pools.put(MAX_PAYLOAD_SIZE, new Stack<ByteBuffer>());
+    }
+
+    public synchronized ByteBuffer allocate(int capacity) {
+        Integer targetSize = getTargetSize(capacity);
+        Stack<ByteBuffer> pool = pools.get(targetSize);
+        if (pool.isEmpty()) {
+            LOG.trace("Creating new buffer of size " + targetSize);
+            return ByteBuffer.allocate(targetSize);
+        } else {
+            return pool.pop();
+        }
+    }
+
+    /**
+     * Returns a buffer that has the size of the Bitmessage network message header, 24 bytes.
+     *
+     * @return a buffer of size 24
+     */
+    public synchronized ByteBuffer allocateHeaderBuffer() {
+        Stack<ByteBuffer> pool = pools.get(HEADER_SIZE);
+        if (pool.isEmpty()) {
+            return ByteBuffer.allocate(HEADER_SIZE);
+        } else {
+            return pool.pop();
+        }
+    }
+
+    public synchronized void deallocate(ByteBuffer buffer) {
+        buffer.clear();
+        Stack<ByteBuffer> pool = pools.get(buffer.capacity());
+        if (pool == null) {
+            throw new IllegalArgumentException("Illegal buffer capacity " + buffer.capacity() +
+                " one of " + pools.keySet() + " expected.");
+        } else {
+            pool.push(buffer);
+        }
+    }
+
+    private Integer getTargetSize(int capacity) {
+        for (Integer size : pools.keySet()) {
+            if (size >= capacity) return size;
+        }
+        throw new IllegalArgumentException("Requested capacity too large: " +
+            "requested=" + capacity + "; max=" + MAX_PAYLOAD_SIZE);
+    }
+}

core/src/main/java/ch/dissem/bitmessage/factory/Factory.java

@@ -23,7 +23,8 @@ import ch.dissem.bitmessage.entity.Plaintext;
 import ch.dissem.bitmessage.entity.payload.*;
 import ch.dissem.bitmessage.entity.valueobject.PrivateKey;
 import ch.dissem.bitmessage.exception.NodeException;
-import ch.dissem.bitmessage.utils.Security;
+import ch.dissem.bitmessage.utils.TTL;
+import ch.dissem.bitmessage.utils.UnixTime;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -32,11 +33,14 @@ import java.io.InputStream;
 import java.net.SocketException;
 import java.net.SocketTimeoutException;
 
+import static ch.dissem.bitmessage.entity.payload.ObjectType.MSG;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
+
 /**
  * Creates {@link NetworkMessage} objects from {@link InputStream InputStreams}
  */
 public class Factory {
-    public static final Logger LOG = LoggerFactory.getLogger(Factory.class);
+    private static final Logger LOG = LoggerFactory.getLogger(Factory.class);
 
     public static NetworkMessage getNetworkMessage(int version, InputStream stream) throws SocketTimeoutException {
         try {
@@ -115,8 +119,8 @@ public class Factory {
         BitmessageAddress temp = new BitmessageAddress(address);
         PrivateKey privateKey = new PrivateKey(privateSigningKey, privateEncryptionKey,
                 createPubkey(temp.getVersion(), temp.getStream(),
-                        Security.createPublicKey(privateSigningKey).getEncoded(false),
-                        Security.createPublicKey(privateEncryptionKey).getEncoded(false),
+                        cryptography().createPublicKey(privateSigningKey),
+                        cryptography().createPublicKey(privateEncryptionKey),
                         nonceTrialsPerByte, extraBytes, behaviourBitfield));
         BitmessageAddress result = new BitmessageAddress(privateKey);
         if (!result.getAddress().equals(address)) {
@@ -126,11 +130,17 @@ public class Factory {
         return result;
     }
 
-    public static BitmessageAddress generatePrivateAddress(boolean shorter, long stream, Pubkey.Feature... features) {
+    public static BitmessageAddress generatePrivateAddress(boolean shorter,
+                                                           long stream,
+                                                           Pubkey.Feature... features) {
         return new BitmessageAddress(new PrivateKey(shorter, stream, 1000, 1000, features));
     }
 
-    static ObjectPayload getObjectPayload(long objectType, long version, long streamNumber, InputStream stream, int length) throws IOException {
+    static ObjectPayload getObjectPayload(long objectType,
+                                          long version,
+                                          long streamNumber,
+                                          InputStream stream,
+                                          int length) throws IOException {
         ObjectType type = ObjectType.fromNumber(objectType);
         if (type != null) {
             switch (type) {
@@ -147,8 +157,8 @@ public class Factory {
             }
         }
         // fallback: just store the message - we don't really care what it is
-//        LOG.info("Unexpected object type: " + objectType);
-        return GenericPayload.read(version, stream, streamNumber, length);
+        LOG.trace("Unexpected object type: " + objectType);
+        return GenericPayload.read(version, streamNumber, stream, length);
     }
 
     private static ObjectPayload parseGetPubkey(long version, long streamNumber, InputStream stream, int length) throws IOException {
@@ -170,7 +180,7 @@ public class Factory {
 
     private static ObjectPayload parsePubkey(long version, long streamNumber, InputStream stream, int length) throws IOException {
         Pubkey pubkey = readPubkey(version, streamNumber, stream, length, true);
-        return pubkey != null ? pubkey : GenericPayload.read(version, stream, streamNumber, length);
+        return pubkey != null ? pubkey : GenericPayload.read(version, streamNumber, stream, length);
     }
 
     private static ObjectPayload parseMsg(long version, long streamNumber, InputStream stream, int length) throws IOException {
@@ -185,15 +195,23 @@ public class Factory {
                 return V5Broadcast.read(stream, streamNumber, length);
             default:
                 LOG.debug("Encountered unknown broadcast version " + version);
-                return GenericPayload.read(version, stream, streamNumber, length);
+                return GenericPayload.read(version, streamNumber, stream, length);
         }
     }
 
-    public static ObjectPayload getBroadcast(BitmessageAddress sendingAddress, Plaintext plaintext) {
+    public static Broadcast getBroadcast(Plaintext plaintext) {
+        BitmessageAddress sendingAddress = plaintext.getFrom();
         if (sendingAddress.getVersion() < 4) {
             return new V4Broadcast(sendingAddress, plaintext);
         } else {
             return new V5Broadcast(sendingAddress, plaintext);
         }
     }
+
+    public static ObjectMessage createAck(Plaintext plaintext) {
+        if (plaintext == null || plaintext.getAckData() == null)
+            return null;
+        GenericPayload ack = new GenericPayload(3, plaintext.getFrom().getStream(), plaintext.getAckData());
+        return new ObjectMessage.Builder().objectType(MSG).payload(ack).expiresTime(UnixTime.now(plaintext.getTTL())).build();
+    }
 }

core/src/main/java/ch/dissem/bitmessage/factory/V3MessageFactory.java

@@ -24,7 +24,6 @@ import ch.dissem.bitmessage.entity.valueobject.NetworkAddress;
 import ch.dissem.bitmessage.exception.NodeException;
 import ch.dissem.bitmessage.utils.AccessCounter;
 import ch.dissem.bitmessage.utils.Decode;
-import ch.dissem.bitmessage.utils.Security;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -33,6 +32,7 @@ import java.io.IOException;
 import java.io.InputStream;
 
 import static ch.dissem.bitmessage.entity.NetworkMessage.MAGIC_BYTES;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 
 /**
  * Creates protocol v3 network messages from {@link InputStream InputStreams}
@@ -44,6 +44,9 @@ class V3MessageFactory {
         findMagic(in);
         String command = getCommand(in);
         int length = (int) Decode.uint32(in);
+        if (length > 1600003) {
+            throw new NodeException("Payload of " + length + " bytes received, no more than 1600003 was expected.");
+        }
         byte[] checksum = Decode.bytes(in, 4);
 
         byte[] payloadBytes = Decode.bytes(in, length);
@@ -59,7 +62,7 @@ class V3MessageFactory {
         }
     }
 
-    private static MessagePayload getPayload(String command, InputStream stream, int length) throws IOException {
+    static MessagePayload getPayload(String command, InputStream stream, int length) throws IOException {
         switch (command) {
             case "version":
                 return parseVersion(stream);
@@ -73,12 +76,18 @@ class V3MessageFactory {
                 return parseGetData(stream);
             case "object":
                 return readObject(stream, length);
+            case "custom":
+                return readCustom(stream, length);
             default:
                 LOG.debug("Unknown command: " + command);
                 return null;
         }
     }
 
+    private static MessagePayload readCustom(InputStream in, int length) throws IOException {
+        return CustomMessage.read(in, length);
+    }
+
     public static ObjectMessage readObject(InputStream in, int length) throws IOException {
         AccessCounter counter = new AccessCounter();
         byte nonce[] = Decode.bytes(in, 8, counter);
@@ -92,18 +101,18 @@ class V3MessageFactory {
         try {
             ByteArrayInputStream dataStream = new ByteArrayInputStream(data);
             payload = Factory.getObjectPayload(objectType, version, stream, dataStream, data.length);
-        } catch (IOException e) {
+        } catch (Exception e) {
             LOG.trace("Could not parse object payload - using generic payload instead", e);
             payload = new GenericPayload(version, stream, data);
         }
 
         return new ObjectMessage.Builder()
-                .nonce(nonce)
-                .expiresTime(expiresTime)
-                .objectType(objectType)
-                .stream(stream)
-                .payload(payload)
-                .build();
+            .nonce(nonce)
+            .expiresTime(expiresTime)
+            .objectType(objectType)
+            .stream(stream)
+            .payload(payload)
+            .build();
     }
 
     private static GetData parseGetData(InputStream stream) throws IOException {
@@ -144,13 +153,13 @@ class V3MessageFactory {
         long[] streamNumbers = Decode.varIntList(stream);
 
         return new Version.Builder()
-                .version(version)
-                .services(services)
-                .timestamp(timestamp)
-                .addrRecv(addrRecv).addrFrom(addrFrom)
-                .nonce(nonce)
-                .userAgent(userAgent)
-                .streams(streamNumbers).build();
+            .version(version)
+            .services(services)
+            .timestamp(timestamp)
+            .addrRecv(addrRecv).addrFrom(addrFrom)
+            .nonce(nonce)
+            .userAgent(userAgent)
+            .streams(streamNumbers).build();
     }
 
     private static InventoryVector parseInventoryVector(InputStream stream) throws IOException {
@@ -170,11 +179,17 @@ class V3MessageFactory {
         long services = Decode.int64(stream);
         byte[] ipv6 = Decode.bytes(stream, 16);
         int port = Decode.uint16(stream);
-        return new NetworkAddress.Builder().time(time).stream(streamNumber).services(services).ipv6(ipv6).port(port).build();
+        return new NetworkAddress.Builder()
+            .time(time)
+            .stream(streamNumber)
+            .services(services)
+            .ipv6(ipv6)
+            .port(port)
+            .build();
     }
 
     private static boolean testChecksum(byte[] checksum, byte[] payload) {
-        byte[] payloadChecksum = Security.sha512(payload);
+        byte[] payloadChecksum = cryptography().sha512(payload);
         for (int i = 0; i < checksum.length; i++) {
             if (checksum[i] != payloadChecksum[i]) {
                 return false;
@@ -185,10 +200,10 @@ class V3MessageFactory {
 
     private static String getCommand(InputStream stream) throws IOException {
         byte[] bytes = new byte[12];
-        int end = -1;
+        int end = bytes.length;
         for (int i = 0; i < bytes.length; i++) {
             bytes[i] = (byte) stream.read();
-            if (end == -1) {
+            if (end == bytes.length) {
                 if (bytes[i] == 0) end = i;
             } else {
                 if (bytes[i] != 0) throw new IOException("'\\0' padding expected for command");

core/src/main/java/ch/dissem/bitmessage/factory/V3MessageReader.java

@@ -0,0 +1,189 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.factory;
+
+import ch.dissem.bitmessage.entity.MessagePayload;
+import ch.dissem.bitmessage.entity.NetworkMessage;
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.exception.NodeException;
+import ch.dissem.bitmessage.utils.Decode;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.nio.ByteBuffer;
+import java.util.LinkedList;
+import java.util.List;
+
+import static ch.dissem.bitmessage.entity.NetworkMessage.MAGIC_BYTES;
+import static ch.dissem.bitmessage.factory.BufferPool.bufferPool;
+import static ch.dissem.bitmessage.ports.NetworkHandler.MAX_PAYLOAD_SIZE;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
+
+/**
+ * Similar to the {@link V3MessageFactory}, but used for NIO buffers which may or may not contain a whole message.
+ */
+public class V3MessageReader {
+    private ByteBuffer headerBuffer;
+    private ByteBuffer dataBuffer;
+
+    private ReaderState state = ReaderState.MAGIC;
+    private String command;
+    private int length;
+    private byte[] checksum;
+
+    private List<NetworkMessage> messages = new LinkedList<>();
+
+    public ByteBuffer getActiveBuffer() {
+        if (state != null && state != ReaderState.DATA) {
+            if (headerBuffer == null) {
+                headerBuffer = bufferPool.allocateHeaderBuffer();
+            }
+        }
+        return state == ReaderState.DATA ? dataBuffer : headerBuffer;
+    }
+
+    public void update() {
+        if (state != ReaderState.DATA) {
+            getActiveBuffer();
+            headerBuffer.flip();
+        }
+        switch (state) {
+            case MAGIC:
+                if (!findMagicBytes(headerBuffer)) {
+                    headerBuffer.compact();
+                    return;
+                }
+                state = ReaderState.HEADER;
+            case HEADER:
+                if (headerBuffer.remaining() < 20) {
+                    headerBuffer.compact();
+                    headerBuffer.limit(20);
+                    return;
+                }
+                command = getCommand(headerBuffer);
+                length = (int) Decode.uint32(headerBuffer);
+                if (length > MAX_PAYLOAD_SIZE) {
+                    throw new NodeException("Payload of " + length + " bytes received, no more than " +
+                        MAX_PAYLOAD_SIZE + " was expected.");
+                }
+                checksum = new byte[4];
+                headerBuffer.get(checksum);
+                state = ReaderState.DATA;
+                bufferPool.deallocate(headerBuffer);
+                headerBuffer = null;
+                dataBuffer = bufferPool.allocate(length);
+                dataBuffer.clear();
+                dataBuffer.limit(length);
+            case DATA:
+                if (dataBuffer.position() < length) {
+                    return;
+                } else {
+                    dataBuffer.flip();
+                }
+                if (!testChecksum(dataBuffer)) {
+                    state = ReaderState.MAGIC;
+                    throw new NodeException("Checksum failed for message '" + command + "'");
+                }
+                try {
+                    MessagePayload payload = V3MessageFactory.getPayload(
+                        command,
+                        new ByteArrayInputStream(dataBuffer.array(),
+                            dataBuffer.arrayOffset() + dataBuffer.position(), length),
+                        length);
+                    if (payload != null) {
+                        messages.add(new NetworkMessage(payload));
+                    }
+                } catch (IOException e) {
+                    throw new NodeException(e.getMessage());
+                } finally {
+                    state = ReaderState.MAGIC;
+                    bufferPool.deallocate(dataBuffer);
+                    dataBuffer = null;
+                    dataBuffer = null;
+                }
+        }
+    }
+
+    public List<NetworkMessage> getMessages() {
+        return messages;
+    }
+
+    private boolean findMagicBytes(ByteBuffer buffer) {
+        int i = 0;
+        while (buffer.hasRemaining()) {
+            if (i == 0) {
+                buffer.mark();
+            }
+            if (buffer.get() == MAGIC_BYTES[i]) {
+                i++;
+                if (i == MAGIC_BYTES.length) {
+                    return true;
+                }
+            } else {
+                i = 0;
+            }
+        }
+        if (i > 0) {
+            buffer.reset();
+        }
+        return false;
+    }
+
+    private static String getCommand(ByteBuffer buffer) {
+        int start = buffer.position();
+        int l = 0;
+        while (l < 12 && buffer.get() != 0) l++;
+        int i = l + 1;
+        while (i < 12) {
+            if (buffer.get() != 0) throw new NodeException("'\\0' padding expected for command");
+            i++;
+        }
+        try {
+            return new String(buffer.array(), start, l, "ASCII");
+        } catch (UnsupportedEncodingException e) {
+            throw new ApplicationException(e);
+        }
+    }
+
+    private boolean testChecksum(ByteBuffer buffer) {
+        byte[] payloadChecksum = cryptography().sha512(buffer.array(),
+            buffer.arrayOffset() + buffer.position(), length);
+        for (int i = 0; i < checksum.length; i++) {
+            if (checksum[i] != payloadChecksum[i]) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * De-allocates all buffers. This method should be called iff the reader isn't used anymore, i.e. when its
+     * connection is severed.
+     */
+    public void cleanup() {
+        state = null;
+        if (headerBuffer != null) {
+            bufferPool.deallocate(headerBuffer);
+        }
+        if (dataBuffer != null) {
+            bufferPool.deallocate(dataBuffer);
+        }
+    }
+
+    private enum ReaderState {MAGIC, HEADER, DATA}
+}

core/src/main/java/ch/dissem/bitmessage/ports/AbstractCryptography.java

@@ -0,0 +1,192 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.InternalContext;
+import ch.dissem.bitmessage.entity.ObjectMessage;
+import ch.dissem.bitmessage.entity.payload.Pubkey;
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.exception.InsufficientProofOfWorkException;
+import ch.dissem.bitmessage.factory.Factory;
+import ch.dissem.bitmessage.utils.Bytes;
+import ch.dissem.bitmessage.utils.UnixTime;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+import java.io.IOException;
+import java.math.BigInteger;
+import java.security.GeneralSecurityException;
+import java.security.MessageDigest;
+import java.security.Provider;
+import java.security.SecureRandom;
+
+import static ch.dissem.bitmessage.InternalContext.NETWORK_EXTRA_BYTES;
+import static ch.dissem.bitmessage.InternalContext.NETWORK_NONCE_TRIALS_PER_BYTE;
+import static ch.dissem.bitmessage.utils.Numbers.max;
+
+/**
+ * Implements everything that isn't directly dependent on either Spongy- or Bouncycastle.
+ */
+public abstract class AbstractCryptography implements Cryptography, InternalContext.ContextHolder {
+    protected static final Logger LOG = LoggerFactory.getLogger(Cryptography.class);
+    private static final SecureRandom RANDOM = new SecureRandom();
+    private static final BigInteger TWO = BigInteger.valueOf(2);
+    private static final BigInteger TWO_POW_64 = TWO.pow(64);
+    private static final BigInteger TWO_POW_16 = TWO.pow(16);
+
+    protected final Provider provider;
+    private InternalContext context;
+
+    protected AbstractCryptography(Provider provider) {
+        this.provider = provider;
+    }
+
+    @Override
+    public void setContext(InternalContext context) {
+        this.context = context;
+    }
+
+    public byte[] sha512(byte[] data, int offset, int length) {
+        MessageDigest mda = md("SHA-512");
+        mda.update(data, offset, length);
+        return mda.digest();
+    }
+
+    public byte[] sha512(byte[]... data) {
+        return hash("SHA-512", data);
+    }
+
+    public byte[] doubleSha512(byte[]... data) {
+        MessageDigest mda = md("SHA-512");
+        for (byte[] d : data) {
+            mda.update(d);
+        }
+        return mda.digest(mda.digest());
+    }
+
+    public byte[] doubleSha512(byte[] data, int length) {
+        MessageDigest mda = md("SHA-512");
+        mda.update(data, 0, length);
+        return mda.digest(mda.digest());
+    }
+
+    public byte[] ripemd160(byte[]... data) {
+        return hash("RIPEMD160", data);
+    }
+
+    public byte[] doubleSha256(byte[] data, int length) {
+        MessageDigest mda = md("SHA-256");
+        mda.update(data, 0, length);
+        return mda.digest(mda.digest());
+    }
+
+    public byte[] sha1(byte[]... data) {
+        return hash("SHA-1", data);
+    }
+
+    public byte[] randomBytes(int length) {
+        byte[] result = new byte[length];
+        RANDOM.nextBytes(result);
+        return result;
+    }
+
+    public void doProofOfWork(ObjectMessage object, long nonceTrialsPerByte,
+                              long extraBytes, ProofOfWorkEngine.Callback callback) {
+        nonceTrialsPerByte = max(nonceTrialsPerByte, NETWORK_NONCE_TRIALS_PER_BYTE);
+        extraBytes = max(extraBytes, NETWORK_EXTRA_BYTES);
+
+        byte[] initialHash = getInitialHash(object);
+
+        byte[] target = getProofOfWorkTarget(object, nonceTrialsPerByte, extraBytes);
+
+        context.getProofOfWorkEngine().calculateNonce(initialHash, target, callback);
+    }
+
+    public void checkProofOfWork(ObjectMessage object, long nonceTrialsPerByte, long extraBytes)
+            throws IOException {
+        byte[] target = getProofOfWorkTarget(object, nonceTrialsPerByte, extraBytes);
+        byte[] value = doubleSha512(object.getNonce(), getInitialHash(object));
+        if (Bytes.lt(target, value, 8)) {
+            throw new InsufficientProofOfWorkException(target, value);
+        }
+    }
+
+    @Override
+    public byte[] getInitialHash(ObjectMessage object) {
+        return sha512(object.getPayloadBytesWithoutNonce());
+    }
+
+    @Override
+    public byte[] getProofOfWorkTarget(ObjectMessage object, long nonceTrialsPerByte, long extraBytes) {
+        if (nonceTrialsPerByte == 0) nonceTrialsPerByte = NETWORK_NONCE_TRIALS_PER_BYTE;
+        if (extraBytes == 0) extraBytes = NETWORK_EXTRA_BYTES;
+
+        BigInteger TTL = BigInteger.valueOf(object.getExpiresTime() - UnixTime.now());
+        BigInteger powLength = BigInteger.valueOf(object.getPayloadBytesWithoutNonce().length + extraBytes);
+        BigInteger denominator = BigInteger.valueOf(nonceTrialsPerByte)
+                .multiply(
+                        powLength.add(
+                                powLength.multiply(TTL).divide(TWO_POW_16)
+                        )
+                );
+        return Bytes.expand(TWO_POW_64.divide(denominator).toByteArray(), 8);
+    }
+
+    private byte[] hash(String algorithm, byte[]... data) {
+        MessageDigest mda = md(algorithm);
+        for (byte[] d : data) {
+            mda.update(d);
+        }
+        return mda.digest();
+    }
+
+    private MessageDigest md(String algorithm) {
+        try {
+            return MessageDigest.getInstance(algorithm, provider);
+        } catch (GeneralSecurityException e) {
+            throw new ApplicationException(e);
+        }
+    }
+
+    public byte[] mac(byte[] key_m, byte[] data) {
+        try {
+            Mac mac = Mac.getInstance("HmacSHA256", provider);
+            mac.init(new SecretKeySpec(key_m, "HmacSHA256"));
+            return mac.doFinal(data);
+        } catch (GeneralSecurityException e) {
+            throw new ApplicationException(e);
+        }
+    }
+
+    public Pubkey createPubkey(long version, long stream, byte[] privateSigningKey, byte[] privateEncryptionKey,
+                               long nonceTrialsPerByte, long extraBytes, Pubkey.Feature... features) {
+        return Factory.createPubkey(version, stream,
+                createPublicKey(privateSigningKey),
+                createPublicKey(privateEncryptionKey),
+                nonceTrialsPerByte, extraBytes, features);
+    }
+
+    public BigInteger keyToBigInt(byte[] privateKey) {
+        return new BigInteger(1, privateKey);
+    }
+
+    public long randomNonce() {
+        return RANDOM.nextLong();
+    }
+}

core/src/main/java/ch/dissem/bitmessage/ports/AbstractMessageRepository.java

@@ -0,0 +1,127 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.InternalContext;
+import ch.dissem.bitmessage.entity.BitmessageAddress;
+import ch.dissem.bitmessage.entity.Plaintext;
+import ch.dissem.bitmessage.entity.valueobject.Label;
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.utils.Strings;
+import ch.dissem.bitmessage.utils.UnixTime;
+
+import java.util.Collection;
+import java.util.List;
+
+import static ch.dissem.bitmessage.utils.SqlStrings.join;
+
+public abstract class AbstractMessageRepository implements MessageRepository, InternalContext.ContextHolder {
+    protected InternalContext ctx;
+
+    @Override
+    public void setContext(InternalContext context) {
+        this.ctx = context;
+    }
+
+    protected void safeSenderIfNecessary(Plaintext message) {
+        if (message.getId() == null) {
+            BitmessageAddress savedAddress = ctx.getAddressRepository().getAddress(message.getFrom().getAddress());
+            if (savedAddress == null) {
+                ctx.getAddressRepository().save(message.getFrom());
+            } else if (savedAddress.getPubkey() == null && message.getFrom().getPubkey() != null) {
+                savedAddress.setPubkey(message.getFrom().getPubkey());
+                ctx.getAddressRepository().save(savedAddress);
+            }
+        }
+    }
+
+    @Override
+    public Plaintext getMessage(Object id) {
+        if (id instanceof Long) {
+            return single(find("id=" + id));
+        } else {
+            throw new IllegalArgumentException("Long expected for ID");
+        }
+    }
+
+    @Override
+    public Plaintext getMessage(byte[] initialHash) {
+        return single(find("initial_hash=X'" + Strings.hex(initialHash) + "'"));
+    }
+
+    @Override
+    public Plaintext getMessageForAck(byte[] ackData) {
+        return single(find("ack_data=X'" + Strings.hex(ackData) + "' AND status='" + Plaintext.Status.SENT + "'"));
+    }
+
+    @Override
+    public List<Plaintext> findMessages(Label label) {
+        if (label == null) {
+            return find("id NOT IN (SELECT message_id FROM Message_Label)");
+        } else {
+            return find("id IN (SELECT message_id FROM Message_Label WHERE label_id=" + label.getId() + ")");
+        }
+    }
+
+    @Override
+    public List<Plaintext> findMessages(Plaintext.Status status, BitmessageAddress recipient) {
+        return find("status='" + status.name() + "' AND recipient='" + recipient.getAddress() + "'");
+    }
+
+    @Override
+    public List<Plaintext> findMessages(Plaintext.Status status) {
+        return find("status='" + status.name() + "'");
+    }
+
+    @Override
+    public List<Plaintext> findMessages(BitmessageAddress sender) {
+        return find("sender='" + sender.getAddress() + "'");
+    }
+
+    @Override
+    public List<Plaintext> findMessagesToResend() {
+        return find("status='" + Plaintext.Status.SENT.name() + "'" +
+                " AND next_try < " + UnixTime.now());
+    }
+
+    @Override
+    public List<Label> getLabels() {
+        return findLabels("1=1");
+    }
+
+    @Override
+    public List<Label> getLabels(Label.Type... types) {
+        return findLabels("type IN (" + join(types) + ")");
+    }
+
+    protected abstract List<Label> findLabels(String where);
+
+
+    protected <T> T single(Collection<T> collection) {
+        switch (collection.size()) {
+            case 0:
+                return null;
+            case 1:
+                return collection.iterator().next();
+            default:
+                throw new ApplicationException("This shouldn't happen, found " + collection.size() +
+                        " items, one or none was expected");
+        }
+    }
+
+    protected abstract List<Plaintext> find(String where);
+}

core/src/main/java/ch/dissem/bitmessage/ports/AddressRepository.java

@@ -30,12 +30,17 @@ public interface AddressRepository {
      */
     List<BitmessageAddress> getIdentities();
 
+    /**
+     * @return all subscribed chans.
+     */
+    List<BitmessageAddress> getChans();
+
     List<BitmessageAddress> getSubscriptions();
 
     List<BitmessageAddress> getSubscriptions(long broadcastVersion);
 
     /**
-     * @return all Bitmessage addresses that have no private key.
+     * @return all Bitmessage addresses that have no private key or are chans.
      */
     List<BitmessageAddress> getContacts();
 

core/src/main/java/ch/dissem/bitmessage/ports/Cryptography.java

@@ -0,0 +1,222 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License. 
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.entity.ObjectMessage;
+import ch.dissem.bitmessage.entity.payload.Pubkey;
+import ch.dissem.bitmessage.exception.InsufficientProofOfWorkException;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.security.MessageDigest;
+import java.security.SecureRandom;
+
+/**
+ * Provides some methods to help with hashing and encryption. All randoms are created using {@link SecureRandom},
+ * which should be secure enough.
+ */
+public interface Cryptography {
+    /**
+     * A helper method to calculate SHA-512 hashes. Please note that a new {@link MessageDigest} object is created at
+     * each call (to ensure thread safety), so you shouldn't use this if you need to do many hash calculations in
+     * success on the same thread.
+     *
+     * @param data   to get hashed
+     * @param offset of the data to be hashed
+     * @param length of the data to be hashed
+     * @return SHA-512 hash of data within the given range
+     */
+    byte[] sha512(byte[] data, int offset, int length);
+
+    /**
+     * A helper method to calculate SHA-512 hashes. Please note that a new {@link MessageDigest} object is created at
+     * each call (to ensure thread safety), so you shouldn't use this if you need to do many hash calculations in
+     * success on the same thread.
+     *
+     * @param data to get hashed
+     * @return SHA-512 hash of data
+     */
+    byte[] sha512(byte[]... data);
+
+    /**
+     * A helper method to calculate doubleSHA-512 hashes. Please note that a new {@link MessageDigest} object is created
+     * at each call (to ensure thread safety), so you shouldn't use this if you need to do many hash calculations in
+     * success on the same thread.
+     *
+     * @param data to get hashed
+     * @return SHA-512 hash of data
+     */
+    byte[] doubleSha512(byte[]... data);
+
+    /**
+     * A helper method to calculate double SHA-512 hashes. This method allows to only use a part of the available bytes
+     * to use for the hash calculation.
+     * <p>
+     * Please note that a new {@link MessageDigest} object is created at each call (to ensure thread safety), so you
+     * shouldn't use this if you need to do many hash calculations in short order on the same thread.
+     * </p>
+     *
+     * @param data   to get hashed
+     * @param length number of bytes to be taken into account
+     * @return SHA-512 hash of data
+     */
+    byte[] doubleSha512(byte[] data, int length);
+
+    /**
+     * A helper method to calculate RIPEMD-160 hashes. Supplying multiple byte arrays has the same result as a
+     * concatenation of all arrays, but might perform better.
+     * <p>
+     * Please note that a new {@link MessageDigest} object is created at
+     * each call (to ensure thread safety), so you shouldn't use this if you need to do many hash calculations in short
+     * order on the same thread.
+     * </p>
+     *
+     * @param data to get hashed
+     * @return RIPEMD-160 hash of data
+     */
+    byte[] ripemd160(byte[]... data);
+
+    /**
+     * A helper method to calculate double SHA-256 hashes. This method allows to only use a part of the available bytes
+     * to use for the hash calculation.
+     * <p>
+     * Please note that a new {@link MessageDigest} object is created at
+     * each call (to ensure thread safety), so you shouldn't use this if you need to do many hash calculations in short
+     * order on the same thread.
+     * </p>
+     *
+     * @param data   to get hashed
+     * @param length number of bytes to be taken into account
+     * @return SHA-256 hash of data
+     */
+    byte[] doubleSha256(byte[] data, int length);
+
+    /**
+     * A helper method to calculate SHA-1 hashes. Supplying multiple byte arrays has the same result as a
+     * concatenation of all arrays, but might perform better.
+     * <p>
+     * Please note that a new {@link MessageDigest} object is created at
+     * each call (to ensure thread safety), so you shouldn't use this if you need to do many hash calculations in short
+     * order on the same thread.
+     * </p>
+     *
+     * @param data to get hashed
+     * @return SHA hash of data
+     */
+    byte[] sha1(byte[]... data);
+
+    /**
+     * @param length number of bytes to return
+     * @return an array of the given size containing random bytes
+     */
+    byte[] randomBytes(int length);
+
+    /**
+     * Calculates the proof of work. This might take a long time, depending on the hardware, message size and time to
+     * live.
+     *
+     * @param object             to do the proof of work for
+     * @param nonceTrialsPerByte difficulty
+     * @param extraBytes         bytes to add to the object size (makes it more difficult to send small messages)
+     * @param callback           to handle nonce once it's calculated
+     */
+    void doProofOfWork(ObjectMessage object, long nonceTrialsPerByte,
+                       long extraBytes, ProofOfWorkEngine.Callback callback);
+
+    /**
+     * @param object             to be checked
+     * @param nonceTrialsPerByte difficulty
+     * @param extraBytes         bytes to add to the object size
+     * @throws InsufficientProofOfWorkException if proof of work doesn't check out (makes it more difficult to send small messages)
+     */
+    void checkProofOfWork(ObjectMessage object, long nonceTrialsPerByte, long extraBytes)
+            throws IOException;
+
+    byte[] getInitialHash(ObjectMessage object);
+
+    byte[] getProofOfWorkTarget(ObjectMessage object, long nonceTrialsPerByte, long extraBytes);
+
+    /**
+     * Calculates the MAC for a message (data)
+     *
+     * @param key_m the symmetric key used
+     * @param data  the message data to calculate the MAC for
+     * @return the MAC
+     */
+    byte[] mac(byte[] key_m, byte[] data);
+
+    /**
+     * @param encrypt if true, encrypts data, otherwise tries to decrypt it.
+     * @param data
+     * @param key_e
+     * @return
+     */
+    byte[] crypt(boolean encrypt, byte[] data, byte[] key_e, byte[] initializationVector);
+
+    /**
+     * Create a new public key fom given private keys.
+     *
+     * @param version              of the public key / address
+     * @param stream               of the address
+     * @param privateSigningKey    private key used for signing
+     * @param privateEncryptionKey private key used for encryption
+     * @param nonceTrialsPerByte   proof of work difficulty
+     * @param extraBytes           bytes to add for the proof of work (make it harder for small messages)
+     * @param features             of the address
+     * @return a public key object
+     */
+    Pubkey createPubkey(long version, long stream, byte[] privateSigningKey, byte[] privateEncryptionKey,
+                        long nonceTrialsPerByte, long extraBytes, Pubkey.Feature... features);
+
+    /**
+     * @param privateKey private key as byte array
+     * @return a public key corresponding to the given private key
+     */
+    byte[] createPublicKey(byte[] privateKey);
+
+    /**
+     * @param privateKey private key as byte array
+     * @return a big integer representation (unsigned) of the given bytes
+     */
+    BigInteger keyToBigInt(byte[] privateKey);
+
+    /**
+     * @param data      to check
+     * @param signature the signature of the message
+     * @param pubkey    the sender's public key
+     * @return true if the signature is valid, false otherwise
+     */
+    boolean isSignatureValid(byte[] data, byte[] signature, Pubkey pubkey);
+
+    /**
+     * Calculate the signature of data, using the given private key.
+     *
+     * @param data       to be signed
+     * @param privateKey to be used for signing
+     * @return the signature
+     */
+    byte[] getSignature(byte[] data, ch.dissem.bitmessage.entity.valueobject.PrivateKey privateKey);
+
+    /**
+     * @return a random number of type long
+     */
+    long randomNonce();
+
+    byte[] multiply(byte[] k, byte[] r);
+
+    byte[] createPoint(byte[] x, byte[] y);
+}

core/src/main/java/ch/dissem/bitmessage/ports/CustomCommandHandler.java

@@ -16,25 +16,12 @@
 
 package ch.dissem.bitmessage.ports;
 
-import ch.dissem.bitmessage.entity.ObjectMessage;
-import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
-import ch.dissem.bitmessage.utils.Property;
-
-import java.io.IOException;
+import ch.dissem.bitmessage.entity.CustomMessage;
+import ch.dissem.bitmessage.entity.MessagePayload;
 
 /**
- * Handles incoming messages
+ * @author Christian Basler
  */
-public interface NetworkHandler {
-    void start(MessageListener listener);
-
-    void stop();
-
-    void offer(InventoryVector iv);
-
-    Property getNetworkStatus();
-
-    interface MessageListener {
-        void receive(ObjectMessage object) throws IOException;
-    }
+public interface CustomCommandHandler {
+    MessagePayload handle(CustomMessage request);
 }

core/src/main/java/ch/dissem/bitmessage/ports/DefaultLabeler.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.InternalContext;
+import ch.dissem.bitmessage.entity.Plaintext;
+import ch.dissem.bitmessage.entity.valueobject.Label;
+
+import static ch.dissem.bitmessage.entity.Plaintext.Status.*;
+
+public class DefaultLabeler implements Labeler, InternalContext.ContextHolder {
+    private InternalContext ctx;
+
+    @Override
+    public void setLabels(Plaintext msg) {
+        msg.setStatus(RECEIVED);
+        if (msg.getType() == Plaintext.Type.BROADCAST) {
+            msg.addLabels(ctx.getMessageRepository().getLabels(Label.Type.INBOX, Label.Type.BROADCAST, Label.Type.UNREAD));
+        } else {
+            msg.addLabels(ctx.getMessageRepository().getLabels(Label.Type.INBOX, Label.Type.UNREAD));
+        }
+    }
+
+    @Override
+    public void markAsDraft(Plaintext msg) {
+        msg.setStatus(DRAFT);
+        msg.addLabels(ctx.getMessageRepository().getLabels(Label.Type.DRAFT));
+    }
+
+    @Override
+    public void markAsSending(Plaintext msg) {
+        if (msg.getTo() != null && msg.getTo().getPubkey() == null) {
+            msg.setStatus(PUBKEY_REQUESTED);
+        } else {
+            msg.setStatus(DOING_PROOF_OF_WORK);
+        }
+        msg.removeLabel(Label.Type.DRAFT);
+        msg.addLabels(ctx.getMessageRepository().getLabels(Label.Type.OUTBOX));
+    }
+
+    @Override
+    public void markAsSent(Plaintext msg) {
+        msg.setStatus(SENT);
+        msg.removeLabel(Label.Type.OUTBOX);
+        msg.addLabels(ctx.getMessageRepository().getLabels(Label.Type.SENT));
+    }
+
+    @Override
+    public void markAsAcknowledged(Plaintext msg) {
+        msg.setStatus(SENT_ACKNOWLEDGED);
+    }
+
+    @Override
+    public void markAsRead(Plaintext msg) {
+        msg.removeLabel(Label.Type.UNREAD);
+    }
+
+    @Override
+    public void markAsUnread(Plaintext msg) {
+        msg.addLabels(ctx.getMessageRepository().getLabels(Label.Type.UNREAD));
+    }
+
+    @Override
+    public void delete(Plaintext msg) {
+        msg.getLabels().clear();
+        msg.addLabels(ctx.getMessageRepository().getLabels(Label.Type.TRASH));
+    }
+
+    @Override
+    public void archive(Plaintext msg) {
+        msg.getLabels().clear();
+    }
+
+    @Override
+    public void setContext(InternalContext ctx) {
+        this.ctx = ctx;
+    }
+}

core/src/main/java/ch/dissem/bitmessage/ports/Inventory.java

@@ -26,15 +26,32 @@ import java.util.List;
  * The Inventory stores and retrieves objects, cleans up outdated objects and can tell which objects are still missing.
  */
 public interface Inventory {
+    /**
+     * Returns the IVs of all valid objects we have for the given streams
+     */
     List<InventoryVector> getInventory(long... streams);
 
+    /**
+     * Returns the IVs of all objects in the offer that we don't have already. Implementations are allowed to
+     * ignore the streams parameter, but it must be set when calling this method.
+     */
     List<InventoryVector> getMissing(List<InventoryVector> offer, long... streams);
 
     ObjectMessage getObject(InventoryVector vector);
 
+    /**
+     * This method is mainly used to search for public keys to newly added addresses or broadcasts from new
+     * subscriptions.
+     */
     List<ObjectMessage> getObjects(long stream, long version, ObjectType... types);
 
     void storeObject(ObjectMessage object);
 
+    boolean contains(ObjectMessage object);
+
+    /**
+     * Deletes all objects that expired 5 minutes ago or earlier
+     * (so we don't accidentally request objects we just deleted)
+     */
     void cleanup();
 }

core/src/main/java/ch/dissem/bitmessage/ports/Labeler.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.entity.Plaintext;
+
+/**
+ * Defines and sets labels. Note that it should also update the status field of a message.
+ * Generally it's highly advised to override the {@link DefaultLabeler} whenever possible,
+ * instead of directly implementing the interface.
+ * <p>
+ * As the labeler gets called whenever the state of a message changes, it can also be used
+ * as a listener.
+ * </p>
+ */
+public interface Labeler {
+    /**
+     * Sets the labels of a newly received message.
+     *
+     * @param msg an unlabeled message or broadcast
+     */
+    void setLabels(Plaintext msg);
+
+    void markAsDraft(Plaintext msg);
+
+    /**
+     * It is paramount that this methods marks the {@link Plaintext} object with status
+     * {@link Plaintext.Status#PUBKEY_REQUESTED} (see {@link DefaultLabeler})
+     */
+    void markAsSending(Plaintext msg);
+
+    void markAsSent(Plaintext msg);
+
+    void markAsAcknowledged(Plaintext msg);
+
+    void markAsRead(Plaintext msg);
+
+    void markAsUnread(Plaintext msg);
+
+    void delete(Plaintext msg);
+
+    void archive(Plaintext msg);
+}

core/src/main/java/ch/dissem/bitmessage/ports/MessageRepository.java

@@ -28,12 +28,24 @@ public interface MessageRepository {
 
     List<Label> getLabels(Label.Type... types);
 
+    int countUnread(Label label);
+
+    Plaintext getMessage(Object id);
+
+    Plaintext getMessage(byte[] initialHash);
+
+    Plaintext getMessageForAck(byte[] ackData);
+
     List<Plaintext> findMessages(Label label);
 
     List<Plaintext> findMessages(Status status);
 
     List<Plaintext> findMessages(Status status, BitmessageAddress recipient);
 
+    List<Plaintext> findMessages(BitmessageAddress sender);
+
+    List<Plaintext> findMessagesToResend();
+
     void save(Plaintext message);
 
     void remove(Plaintext message);

core/src/main/java/ch/dissem/bitmessage/ports/MultiThreadedPOWEngine.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.utils.Bytes;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.*;
+
+import static ch.dissem.bitmessage.utils.Bytes.inc;
+import static ch.dissem.bitmessage.utils.ThreadFactoryBuilder.pool;
+
+/**
+ * A POW engine using all available CPU cores.
+ */
+public class MultiThreadedPOWEngine implements ProofOfWorkEngine {
+    private static final Logger LOG = LoggerFactory.getLogger(MultiThreadedPOWEngine.class);
+    private final ExecutorService waiterPool = Executors.newSingleThreadExecutor(pool("POW-waiter").daemon().build());
+    private final ExecutorService workerPool = Executors.newCachedThreadPool(pool("POW-worker").daemon().build());
+
+    /**
+     * This method will block until all pending nonce calculations are done, but not wait for its own calculation
+     * to finish.
+     * (This implementation becomes very inefficient if multiple nonce are calculated at the same time.)
+     *
+     * @param initialHash the SHA-512 hash of the object to send, sans nonce
+     * @param target      the target, representing an unsigned long
+     * @param callback    called with the calculated nonce as argument. The ProofOfWorkEngine implementation must make
+     */
+    @Override
+    public void calculateNonce(final byte[] initialHash, final byte[] target, final Callback callback) {
+        waiterPool.execute(new Runnable() {
+            @Override
+            public void run() {
+                long startTime = System.currentTimeMillis();
+
+                int cores = Runtime.getRuntime().availableProcessors();
+                if (cores > 255) cores = 255;
+                LOG.info("Doing POW using " + cores + " cores");
+                List<Worker> workers = new ArrayList<>(cores);
+                for (int i = 0; i < cores; i++) {
+                    Worker w = new Worker((byte) cores, i, initialHash, target);
+                    workers.add(w);
+                }
+                List<Future<byte[]>> futures = new ArrayList<>(cores);
+                for (Worker w : workers) {
+                    // Doing this in the previous loop might cause a ConcurrentModificationException in the worker
+                    // if a worker finds a nonce while new ones are still being added.
+                    futures.add(workerPool.submit(w));
+                }
+                try {
+                    while (!Thread.interrupted()) {
+                        for (Future<byte[]> future : futures) {
+                            if (future.isDone()) {
+                                callback.onNonceCalculated(initialHash, future.get());
+                                LOG.info("Nonce calculated in " + ((System.currentTimeMillis() - startTime) / 1000) + " seconds");
+                                for (Future<byte[]> f : futures) {
+                                    f.cancel(true);
+                                }
+                                return;
+                            }
+                        }
+                        Thread.sleep(100);
+                    }
+                    LOG.error("POW waiter thread interrupted - this should not happen!");
+                } catch (ExecutionException e) {
+                    LOG.error(e.getMessage(), e);
+                } catch (InterruptedException e) {
+                    LOG.error("POW waiter thread interrupted - this should not happen!", e);
+                }
+            }
+        });
+    }
+
+    private class Worker implements Callable<byte[]> {
+        private final byte numberOfCores;
+        private final byte[] initialHash;
+        private final byte[] target;
+        private final MessageDigest mda;
+        private final byte[] nonce = new byte[8];
+
+        Worker(byte numberOfCores, int core, byte[] initialHash, byte[] target) {
+            this.numberOfCores = numberOfCores;
+            this.initialHash = initialHash;
+            this.target = target;
+            this.nonce[7] = (byte) core;
+            try {
+                mda = MessageDigest.getInstance("SHA-512");
+            } catch (NoSuchAlgorithmException e) {
+                LOG.error(e.getMessage(), e);
+                throw new ApplicationException(e);
+            }
+        }
+
+        @Override
+        public byte[] call() throws Exception {
+            do {
+                inc(nonce, numberOfCores);
+                mda.update(nonce);
+                mda.update(initialHash);
+                if (!Bytes.lt(target, mda.digest(mda.digest()), 8)) {
+                    return nonce;
+                }
+            } while (!Thread.interrupted());
+            return null;
+        }
+    }
+}

core/src/main/java/ch/dissem/bitmessage/ports/NetworkHandler.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.entity.CustomMessage;
+import ch.dissem.bitmessage.entity.ObjectMessage;
+import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
+import ch.dissem.bitmessage.utils.Property;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.util.Collection;
+import java.util.concurrent.Future;
+
+/**
+ * Handles incoming messages
+ */
+public interface NetworkHandler {
+    int NETWORK_MAGIC_NUMBER = 8;
+    int HEADER_SIZE = 24;
+    int MAX_PAYLOAD_SIZE = 1600003;
+    int MAX_MESSAGE_SIZE = HEADER_SIZE + MAX_PAYLOAD_SIZE;
+
+    /**
+     * Connects to the trusted host, fetches and offers new messages and disconnects afterwards.
+     * <p>
+     * An implementation should disconnect if either the timeout is reached or the returned thread is interrupted.
+     * </p>
+     */
+    Future<?> synchronize(InetAddress server, int port, long timeoutInSeconds);
+
+    /**
+     * Send a custom message to a specific node (that should implement handling for this message type) and returns
+     * the response, which in turn is expected to be a {@link CustomMessage}.
+     *
+     * @param server  the node's address
+     * @param port    the node's port
+     * @param request the request
+     * @return the response
+     */
+    CustomMessage send(InetAddress server, int port, CustomMessage request);
+
+    /**
+     * Start a full network node, accepting incoming connections and relaying objects.
+     */
+    void start();
+
+    /**
+     * Stop the full network node.
+     */
+    void stop();
+
+    /**
+     * Offer new objects to up to 8 random nodes.
+     */
+    void offer(InventoryVector iv);
+
+    /**
+     * Request each of those objects from a node that knows of the requested object.
+     *
+     * @param inventoryVectors of the objects to be requested
+     */
+    void request(Collection<InventoryVector> inventoryVectors);
+
+    Property getNetworkStatus();
+
+    boolean isRunning();
+
+    interface MessageListener {
+        void receive(ObjectMessage object) throws IOException;
+    }
+}

core/src/main/java/ch/dissem/bitmessage/ports/NodeRegistryHelper.java

@@ -0,0 +1,54 @@
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.entity.valueobject.NetworkAddress;
+import ch.dissem.bitmessage.exception.ApplicationException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.InetAddress;
+import java.util.*;
+
+/**
+ * Helper class to kick start node registries.
+ */
+public class NodeRegistryHelper {
+    private static final Logger LOG = LoggerFactory.getLogger(NodeRegistryHelper.class);
+
+    public static Map<Long, Set<NetworkAddress>> loadStableNodes() {
+        try (InputStream in = NodeRegistryHelper.class.getClassLoader().getResourceAsStream("nodes.txt")) {
+            Scanner scanner = new Scanner(in);
+            long stream = 0;
+            Map<Long, Set<NetworkAddress>> result = new HashMap<>();
+            Set<NetworkAddress> streamSet = null;
+            while (scanner.hasNext()) {
+                try {
+                    String line = scanner.nextLine().trim();
+                    if (line.startsWith("[stream")) {
+                        stream = Long.parseLong(line.substring(8, line.lastIndexOf(']')));
+                        streamSet = new HashSet<>();
+                        result.put(stream, streamSet);
+                    } else if (streamSet != null && !line.isEmpty() && !line.startsWith("#")) {
+                        int portIndex = line.lastIndexOf(':');
+                        InetAddress[] inetAddresses = InetAddress.getAllByName(line.substring(0, portIndex));
+                        int port = Integer.valueOf(line.substring(portIndex + 1));
+                        for (InetAddress inetAddress : inetAddresses) {
+                            streamSet.add(new NetworkAddress.Builder().ip(inetAddress).port(port).stream(stream).build());
+                        }
+                    }
+                } catch (IOException e) {
+                    LOG.warn(e.getMessage(), e);
+                }
+            }
+            if (LOG.isDebugEnabled()) {
+                for (Map.Entry<Long, Set<NetworkAddress>> e : result.entrySet()) {
+                    LOG.debug("Stream " + e.getKey() + ": loaded " + e.getValue().size() + " bootstrap nodes.");
+                }
+            }
+            return result;
+        } catch (IOException e) {
+            throw new ApplicationException(e);
+        }
+    }
+}

core/src/main/java/ch/dissem/bitmessage/ports/ProofOfWorkEngine.java

@@ -24,9 +24,17 @@ public interface ProofOfWorkEngine {
      * Returns a nonce, such that the first 8 bytes from sha512(sha512(nonce||initialHash)) represent a unsigned long
      * smaller than target.
      *
-     * @param initialHash        the SHA-512 hash of the object to send, sans nonce
-     * @param target             the target, representing an unsigned long
-     * @return 8 bytes nonce
+     * @param initialHash the SHA-512 hash of the object to send, sans nonce
+     * @param target      the target, representing an unsigned long
+     * @param callback    called with the calculated nonce as argument. The ProofOfWorkEngine implementation must make
+     *                    sure this is only called once.
      */
-    byte[] calculateNonce(byte[] initialHash, byte[] target);
+    void calculateNonce(byte[] initialHash, byte[] target, Callback callback);
+
+    interface Callback {
+        /**
+         * @param nonce 8 bytes nonce
+         */
+        void onNonceCalculated(byte[] initialHash, byte[] nonce);
+    }
 }

core/src/main/java/ch/dissem/bitmessage/ports/ProofOfWorkRepository.java

@@ -0,0 +1,45 @@
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.entity.ObjectMessage;
+import ch.dissem.bitmessage.entity.Plaintext;
+
+import java.util.List;
+
+/**
+ * Objects that proof of work is currently being done for.
+ *
+ * @author Christian Basler
+ */
+public interface ProofOfWorkRepository {
+    Item getItem(byte[] initialHash);
+
+    List<byte[]> getItems();
+
+    void putObject(ObjectMessage object, long nonceTrialsPerByte, long extraBytes);
+
+    void putObject(Item item);
+
+    void removeObject(byte[] initialHash);
+
+    class Item {
+        public final ObjectMessage object;
+        public final long nonceTrialsPerByte;
+        public final long extraBytes;
+
+        // Needed for ACK POW calculation
+        public final Long expirationTime;
+        public final Plaintext message;
+
+        public Item(ObjectMessage object, long nonceTrialsPerByte, long extraBytes) {
+            this(object, nonceTrialsPerByte, extraBytes, 0, null);
+        }
+
+        public Item(ObjectMessage object, long nonceTrialsPerByte, long extraBytes, long expirationTime, Plaintext message) {
+            this.object = object;
+            this.nonceTrialsPerByte = nonceTrialsPerByte;
+            this.extraBytes = extraBytes;
+            this.expirationTime = expirationTime;
+            this.message = message;
+        }
+    }
+}

core/src/main/java/ch/dissem/bitmessage/ports/SimplePOWEngine.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.exception.ApplicationException;
+import ch.dissem.bitmessage.utils.Bytes;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+import static ch.dissem.bitmessage.utils.Bytes.inc;
+
+/**
+ * You should really use the MultiThreadedPOWEngine, but this one might help you grok the other one.
+ * <p>
+ * <strong>Warning:</strong> implementations probably depend on POW being asynchronous, that's
+ * another reason not to use this one.
+ * </p>
+ */
+public class SimplePOWEngine implements ProofOfWorkEngine {
+    @Override
+    public void calculateNonce(byte[] initialHash, byte[] target, Callback callback) {
+        try {
+            MessageDigest mda = MessageDigest.getInstance("SHA-512");
+            byte[] nonce = new byte[8];
+            do {
+                inc(nonce);
+                mda.update(nonce);
+                mda.update(initialHash);
+            } while (Bytes.lt(target, mda.digest(mda.digest()), 8));
+            callback.onNonceCalculated(initialHash, nonce);
+        } catch (NoSuchAlgorithmException e) {
+            throw new ApplicationException(e);
+        }
+    }
+}

core/src/main/java/ch/dissem/bitmessage/utils/Base58.java

@@ -18,6 +18,7 @@
 package ch.dissem.bitmessage.utils;
 
 import ch.dissem.bitmessage.exception.AddressFormatException;
+import ch.dissem.bitmessage.exception.ApplicationException;
 
 import java.io.UnsupportedEncodingException;
 
@@ -30,7 +31,7 @@ import static java.util.Arrays.copyOfRange;
  */
 public class Base58 {
     private static final int[] INDEXES = new int[128];
-    private static char[] ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz".toCharArray();
+    private static final char[] ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz".toCharArray();
 
     static {
         for (int i = 0; i < INDEXES.length; i++) {
@@ -44,27 +45,27 @@ public class Base58 {
     /**
      * Encodes the given bytes in base58. No checksum is appended.
      *
-     * @param input to encode
+     * @param data to encode
      * @return base58 encoded input
      */
-    public static String encode(byte[] input) {
-        if (input.length == 0) {
+    public static String encode(byte[] data) {
+        if (data.length == 0) {
             return "";
         }
-        input = copyOfRange(input, 0, input.length);
+        final byte[] bytes = copyOfRange(data, 0, data.length);
         // Count leading zeroes.
         int zeroCount = 0;
-        while (zeroCount < input.length && input[zeroCount] == 0) {
+        while (zeroCount < bytes.length && bytes[zeroCount] == 0) {
             ++zeroCount;
         }
         // The actual encoding.
-        byte[] temp = new byte[input.length * 2];
+        byte[] temp = new byte[bytes.length * 2];
         int j = temp.length;
 
         int startAt = zeroCount;
-        while (startAt < input.length) {
-            byte mod = divmod58(input, startAt);
-            if (input[startAt] == 0) {
+        while (startAt < bytes.length) {
+            byte mod = divmod58(bytes, startAt);
+            if (bytes[startAt] == 0) {
                 ++startAt;
             }
             temp[--j] = (byte) ALPHABET[mod];
@@ -83,7 +84,7 @@ public class Base58 {
         try {
             return new String(output, "US-ASCII");
         } catch (UnsupportedEncodingException e) {
-            throw new RuntimeException(e);  // Cannot happen.
+            throw new ApplicationException(e);  // Cannot happen.
         }
     }
 
@@ -97,7 +98,7 @@ public class Base58 {
             char c = input.charAt(i);
 
             int digit58 = -1;
-            if (c >= 0 && c < 128) {
+            if (c < 128) {
                 digit58 = INDEXES[c];
             }
             if (digit58 < 0) {

core/src/main/java/ch/dissem/bitmessage/utils/Bytes.java

@@ -16,12 +16,6 @@
 
 package ch.dissem.bitmessage.utils;
 
-import ch.dissem.bitmessage.entity.Streamable;
-
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.util.Arrays;
-
 /**
  * A helper class for working with byte arrays interpreted as unsigned big endian integers.
  * This is one part due to the fact that Java doesn't support unsigned numbers, and another
@@ -29,6 +23,8 @@ import java.util.Arrays;
  * situations.
  */
 public class Bytes {
+    public static final byte BYTE_0x80 = (byte) 0x80;
+
     public static void inc(byte[] nonce) {
         for (int i = nonce.length - 1; i >= 0; i--) {
             nonce[i]++;
@@ -88,9 +84,7 @@ public class Bytes {
     }
 
     private static boolean lt(byte a, byte b) {
-        if (a < 0) return b < 0 && a < b;
-        if (b < 0) return a >= 0 || a < b;
-        return a < b;
+        return (a ^ BYTE_0x80) < (b ^ BYTE_0x80);
     }
 
     /**

core/src/main/java/ch/dissem/bitmessage/utils/CallbackWaiter.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.utils;
+
+/**
+ * Waits for a value within a callback method to be set.
+ */
+public class CallbackWaiter<T> {
+    private final long startTime = System.currentTimeMillis();
+    private volatile boolean isSet;
+    private T value;
+    private long time;
+
+    public void setValue(T value) {
+        synchronized (this) {
+            this.time = System.currentTimeMillis() - startTime;
+            this.value = value;
+            this.isSet = true;
+        }
+    }
+
+    public T waitForValue() throws InterruptedException {
+        while (!isSet) {
+            Thread.sleep(100);
+        }
+        synchronized (this) {
+            return value;
+        }
+    }
+
+    public long getTime() {
+        return time;
+    }
+}

core/src/main/java/ch/dissem/bitmessage/utils/Decode.java

@@ -0,0 +1,152 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.utils;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.ByteBuffer;
+
+import static ch.dissem.bitmessage.utils.AccessCounter.inc;
+
+/**
+ * This class handles decoding simple types from byte stream, according to
+ * https://bitmessage.org/wiki/Protocol_specification#Common_structures
+ */
+public class Decode {
+    public static byte[] shortVarBytes(InputStream in, AccessCounter counter) throws IOException {
+        int length = uint16(in, counter);
+        return bytes(in, length, counter);
+    }
+
+    public static byte[] varBytes(InputStream in) throws IOException {
+        return varBytes(in, null);
+    }
+
+    public static byte[] varBytes(InputStream in, AccessCounter counter) throws IOException {
+        int length = (int) varInt(in, counter);
+        return bytes(in, length, counter);
+    }
+
+    public static byte[] bytes(InputStream in, int count) throws IOException {
+        return bytes(in, count, null);
+    }
+
+    public static byte[] bytes(InputStream in, int count, AccessCounter counter) throws IOException {
+        byte[] result = new byte[count];
+        int off = 0;
+        while (off < count) {
+            int read = in.read(result, off, count - off);
+            if (read < 0) {
+                throw new IOException("Unexpected end of stream, wanted to read " + count + " bytes but only got " + off);
+            }
+            off += read;
+        }
+        inc(counter, count);
+        return result;
+    }
+
+    public static long[] varIntList(InputStream in) throws IOException {
+        int length = (int) varInt(in);
+        long[] result = new long[length];
+
+        for (int i = 0; i < length; i++) {
+            result[i] = varInt(in);
+        }
+        return result;
+    }
+
+    public static long varInt(InputStream in) throws IOException {
+        return varInt(in, null);
+    }
+
+    public static long varInt(InputStream in, AccessCounter counter) throws IOException {
+        int first = in.read();
+        inc(counter);
+        switch (first) {
+            case 0xfd:
+                return uint16(in, counter);
+            case 0xfe:
+                return uint32(in, counter);
+            case 0xff:
+                return int64(in, counter);
+            default:
+                return first;
+        }
+    }
+
+    public static int uint8(InputStream in) throws IOException {
+        return in.read();
+    }
+
+    public static int uint16(InputStream in) throws IOException {
+        return uint16(in, null);
+    }
+
+    public static int uint16(InputStream in, AccessCounter counter) throws IOException {
+        inc(counter, 2);
+        return in.read() << 8 | in.read();
+    }
+
+    public static long uint32(InputStream in) throws IOException {
+        return uint32(in, null);
+    }
+
+    public static long uint32(InputStream in, AccessCounter counter) throws IOException {
+        inc(counter, 4);
+        return in.read() << 24 | in.read() << 16 | in.read() << 8 | in.read();
+    }
+
+    public static long uint32(ByteBuffer in) {
+        return u(in.get()) << 24 | u(in.get()) << 16 | u(in.get()) << 8 | u(in.get());
+    }
+
+    public static int int32(InputStream in) throws IOException {
+        return int32(in, null);
+    }
+
+    public static int int32(InputStream in, AccessCounter counter) throws IOException {
+        inc(counter, 4);
+        return ByteBuffer.wrap(bytes(in, 4)).getInt();
+    }
+
+    public static long int64(InputStream in) throws IOException {
+        return int64(in, null);
+    }
+
+    public static long int64(InputStream in, AccessCounter counter) throws IOException {
+        inc(counter, 8);
+        return ByteBuffer.wrap(bytes(in, 8)).getLong();
+    }
+
+    public static String varString(InputStream in) throws IOException {
+        return varString(in, null);
+    }
+
+    public static String varString(InputStream in, AccessCounter counter) throws IOException {
+        int length = (int) varInt(in, counter);
+        // FIXME: technically, it says the length in characters, but I think this one might be correct
+        // otherwise it will get complicated, as we'll need to read UTF-8 char by char...
+        return new String(bytes(in, length, counter), "utf-8");
+    }
+
+    /**
+     * Returns the given byte as if it were unsigned.
+     */
+    private static int u(byte b) {
+        return b & 0xFF;
+    }
+}

core/src/main/java/ch/dissem/bitmessage/utils/Encode.java

@@ -17,10 +17,13 @@
 package ch.dissem.bitmessage.utils;
 
 import ch.dissem.bitmessage.entity.Streamable;
+import ch.dissem.bitmessage.exception.ApplicationException;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.UnsupportedEncodingException;
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 
 import static ch.dissem.bitmessage.utils.AccessCounter.inc;
@@ -37,36 +40,54 @@ public class Encode {
         }
     }
 
+    public static void varIntList(long[] values, ByteBuffer buffer) {
+        varInt(values.length, buffer);
+        for (long value : values) {
+            varInt(value, buffer);
+        }
+    }
+
     public static void varInt(long value, OutputStream stream) throws IOException {
         varInt(value, stream, null);
     }
 
-    public static void varInt(long value, OutputStream stream, AccessCounter counter) throws IOException {
+    public static void varInt(long value, ByteBuffer buffer) {
         if (value < 0) {
             // This is due to the fact that Java doesn't really support unsigned values.
             // Please be aware that this might be an error due to a smaller negative value being cast to long.
-            // Normally, negative values shouldn't occur within the protocol, and I large enough longs
-            // to being recognized as negatives aren't realistic.
-            stream.write(0xff);
-            inc(counter);
-            int64(value, stream, counter);
+            // Normally, negative values shouldn't occur within the protocol, and longs large enough for being
+            // recognized as negatives aren't realistic.
+            buffer.put((byte) 0xff);
+            buffer.putLong(value);
         } else if (value < 0xfd) {
-            int8(value, stream, counter);
+            buffer.put((byte) value);
         } else if (value <= 0xffffL) {
-            stream.write(0xfd);
-            inc(counter);
-            int16(value, stream, counter);
+            buffer.put((byte) 0xfd);
+            buffer.putShort((short) value);
         } else if (value <= 0xffffffffL) {
-            stream.write(0xfe);
-            inc(counter);
-            int32(value, stream, counter);
+            buffer.put((byte) 0xfe);
+            buffer.putInt((int) value);
         } else {
-            stream.write(0xff);
-            inc(counter);
-            int64(value, stream, counter);
+            buffer.put((byte) 0xff);
+            buffer.putLong(value);
         }
     }
 
+    public static byte[] varInt(long value) {
+        ByteBuffer buffer = ByteBuffer.allocate(9);
+        varInt(value, buffer);
+        buffer.flip();
+        return Bytes.truncate(buffer.array(), buffer.limit());
+    }
+
+    public static void varInt(long value, OutputStream stream, AccessCounter counter) throws IOException {
+        ByteBuffer buffer = ByteBuffer.allocate(9);
+        varInt(value, buffer);
+        buffer.flip();
+        stream.write(buffer.array(), 0, buffer.limit());
+        inc(counter, buffer.limit());
+    }
+
     public static void int8(long value, OutputStream stream) throws IOException {
         int8(value, stream, null);
     }
@@ -81,10 +102,14 @@ public class Encode {
     }
 
     public static void int16(long value, OutputStream stream, AccessCounter counter) throws IOException {
-        stream.write(ByteBuffer.allocate(4).putInt((int) value).array(), 2, 2);
+        stream.write(ByteBuffer.allocate(2).putShort((short) value).array());
         inc(counter, 2);
     }
 
+    public static void int16(long value, ByteBuffer buffer) {
+        buffer.putShort((short) value);
+    }
+
     public static void int32(long value, OutputStream stream) throws IOException {
         int32(value, stream, null);
     }
@@ -94,6 +119,10 @@ public class Encode {
         inc(counter, 4);
     }
 
+    public static void int32(long value, ByteBuffer buffer) {
+        buffer.putInt((int) value);
+    }
+
     public static void int64(long value, OutputStream stream) throws IOException {
         int64(value, stream, null);
     }
@@ -103,22 +132,57 @@ public class Encode {
         inc(counter, 8);
     }
 
-    public static void varString(String value, OutputStream stream) throws IOException {
+    public static void int64(long value, ByteBuffer buffer) {
+        buffer.putLong(value);
+    }
+
+    public static void varString(String value, OutputStream out) throws IOException {
         byte[] bytes = value.getBytes("utf-8");
-        // FIXME: technically, it says the length in characters, but I think this one might be correct
+        // Technically, it says the length in characters, but I think this one might be correct.
+        // It doesn't really matter, as only ASCII characters are being used.
         // see also Decode#varString()
-        varInt(bytes.length, stream);
-        stream.write(bytes);
+        varInt(bytes.length, out);
+        out.write(bytes);
+    }
+
+    public static void varString(String value, ByteBuffer buffer) {
+        try {
+            byte[] bytes = value.getBytes("utf-8");
+            // Technically, it says the length in characters, but I think this one might be correct.
+            // It doesn't really matter, as only ASCII characters are being used.
+            // see also Decode#varString()
+            buffer.put(varInt(bytes.length));
+            buffer.put(bytes);
+        } catch (UnsupportedEncodingException e) {
+            throw new ApplicationException(e);
+        }
+    }
+
+    public static void varBytes(byte[] data, OutputStream out) throws IOException {
+        varInt(data.length, out);
+        out.write(data);
+    }
+
+    public static void varBytes(byte[] data, ByteBuffer buffer) {
+        varInt(data.length, buffer);
+        buffer.put(data);
     }
 
     /**
+     * Serializes a {@link Streamable} object and returns the byte array.
+     *
      * @param streamable the object to be serialized
      * @return an array of bytes representing the given streamable object.
-     * @throws IOException if an I/O error occurs.
      */
-    public static byte[] bytes(Streamable streamable) throws IOException {
+    public static byte[] bytes(Streamable streamable) {
+        if (streamable == null) return null;
+
         ByteArrayOutputStream stream = new ByteArrayOutputStream();
-        streamable.write(stream);
+        try {
+            streamable.write(stream);
+        } catch (IOException e) {
+            throw new ApplicationException(e);
+        }
         return stream.toByteArray();
     }
 
@@ -126,11 +190,14 @@ public class Encode {
      * @param streamable the object to be serialized
      * @param padding    the result will be padded such that its length is a multiple of <em>padding</em>
      * @return the bytes of the given {@link Streamable} object, 0-padded such that the final length is x*padding.
-     * @throws IOException if an I/O error occurs.
      */
-    public static byte[] bytes(Streamable streamable, int padding) throws IOException {
+    public static byte[] bytes(Streamable streamable, int padding) {
         ByteArrayOutputStream stream = new ByteArrayOutputStream();
-        streamable.write(stream);
+        try {
+            streamable.write(stream);
+        } catch (IOException e) {
+            throw new ApplicationException(e);
+        }
         int offset = padding - stream.size() % padding;
         int length = stream.size() + offset;
         byte[] result = new byte[length];

core/src/main/java/ch/dissem/bitmessage/utils/Numbers.java

@@ -0,0 +1,10 @@
+package ch.dissem.bitmessage.utils;
+
+/**
+ * @author Christian Basler
+ */
+public class Numbers {
+    public static long max(long a, long b) {
+        return a > b ? a : b;
+    }
+}

core/src/main/java/ch/dissem/bitmessage/utils/Points.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.utils;
+
+import java.util.Arrays;
+
+/**
+ * Created by chris on 20.07.15.
+ */
+public class Points {
+    public static byte[] getX(byte[] P) {
+        return Arrays.copyOfRange(P, 1, ((P.length - 1) / 2) + 1);
+    }
+
+    public static byte[] getY(byte[] P) {
+        return Arrays.copyOfRange(P, ((P.length - 1) / 2) + 1, P.length);
+    }
+}

core/src/main/java/ch/dissem/bitmessage/utils/Property.java

@@ -16,8 +16,16 @@
 
 package ch.dissem.bitmessage.utils;
 
+import java.util.Arrays;
+import java.util.Objects;
+
 /**
- * Created by chris on 14.06.15.
+ * Some property that has a name, a value and/or other properties. This can be used for any purpose, but is for now
+ * used to contain different status information. It is by default displayed in some JSON inspired human readable
+ * notation, but you might only want to rely on the 'human readable' part.
+ * <p>
+ * If you need a real JSON representation, please add a method <code>toJson()</code>.
+ * </p>
  */
 public class Property {
     private String name;
@@ -30,6 +38,36 @@ public class Property {
         this.properties = properties;
     }
 
+    public String getName() {
+        return name;
+    }
+
+    public Object getValue() {
+        return value;
+    }
+
+    /**
+     * Returns the property if available or <code>null</code> otherwise.
+     * Subproperties can be requested by submitting the sequence of properties.
+     */
+    public Property getProperty(String... name) {
+        if (name == null || name.length == 0) return null;
+
+        for (Property p : properties) {
+            if (Objects.equals(name[0], p.name)) {
+                if (name.length == 1)
+                    return p;
+                else
+                    return p.getProperty(Arrays.copyOfRange(name, 1, name.length));
+            }
+        }
+        return null;
+    }
+
+    public Property[] getProperties() {
+        return properties;
+    }
+
     @Override
     public String toString() {
         return toString("");

core/src/main/java/ch/dissem/bitmessage/utils/Singleton.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.utils;
+
+import ch.dissem.bitmessage.ports.Cryptography;
+
+/**
+ * @author Christian Basler
+ */
+public class Singleton {
+    private static Cryptography cryptography;
+
+    public static void initialize(Cryptography cryptography) {
+        synchronized (Singleton.class) {
+            Singleton.cryptography = cryptography;
+        }
+    }
+
+    public static Cryptography cryptography() {
+        return cryptography;
+    }
+}

core/src/main/java/ch/dissem/bitmessage/utils/SqlStrings.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.utils;
+
+import ch.dissem.bitmessage.entity.payload.ObjectType;
+
+import static ch.dissem.bitmessage.utils.Strings.hex;
+
+public class SqlStrings {
+    public static StringBuilder join(long... objects) {
+        StringBuilder streamList = new StringBuilder();
+        for (int i = 0; i < objects.length; i++) {
+            if (i > 0) streamList.append(", ");
+            streamList.append(objects[i]);
+        }
+        return streamList;
+    }
+
+    public static StringBuilder join(byte[]... objects) {
+        StringBuilder streamList = new StringBuilder();
+        for (int i = 0; i < objects.length; i++) {
+            if (i > 0) streamList.append(", ");
+            streamList.append(hex(objects[i]));
+        }
+        return streamList;
+    }
+
+    public static StringBuilder join(ObjectType... types) {
+        StringBuilder streamList = new StringBuilder();
+        for (int i = 0; i < types.length; i++) {
+            if (i > 0) streamList.append(", ");
+            streamList.append(types[i].getNumber());
+        }
+        return streamList;
+    }
+
+    public static StringBuilder join(Enum... types) {
+        StringBuilder streamList = new StringBuilder();
+        for (int i = 0; i < types.length; i++) {
+            if (i > 0) streamList.append(", ");
+            streamList.append('\'').append(types[i].name()).append('\'');
+        }
+        return streamList;
+    }
+}

core/src/main/java/ch/dissem/bitmessage/utils/Strings.java

@@ -16,8 +16,6 @@
 
 package ch.dissem.bitmessage.utils;
 
-import ch.dissem.bitmessage.entity.payload.ObjectType;
-
 /**
  * Some utilities to handle strings.
  * TODO: Probably this should be split in a GUI related and an SQL related utility class.

core/src/main/java/ch/dissem/bitmessage/utils/TTL.java

@@ -0,0 +1,40 @@
+package ch.dissem.bitmessage.utils;
+
+import static ch.dissem.bitmessage.utils.UnixTime.DAY;
+
+/**
+ * Stores times to live for different object types. Usually this shouldn't be messed with,
+ * but for tests it might be a good idea to reduce it to a minimum, and on mobile clients
+ * you might want to optimize it as well.
+ *
+ * @author Christian Basler
+ */
+public class TTL {
+    private static long msg = 2 * DAY;
+    private static long getpubkey = 2 * DAY;
+    private static long pubkey = 28 * DAY;
+
+    public static long msg() {
+        return msg;
+    }
+
+    public static void msg(long msg) {
+        TTL.msg = msg;
+    }
+
+    public static long getpubkey() {
+        return getpubkey;
+    }
+
+    public static void getpubkey(long getpubkey) {
+        TTL.getpubkey = getpubkey;
+    }
+
+    public static long pubkey() {
+        return pubkey;
+    }
+
+    public static void pubkey(long pubkey) {
+        TTL.pubkey = pubkey;
+    }
+}

core/src/main/java/ch/dissem/bitmessage/utils/ThreadFactoryBuilder.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.utils;
+
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class ThreadFactoryBuilder {
+    private final String namePrefix;
+    private int prio = Thread.NORM_PRIORITY;
+    private boolean daemon = false;
+
+    private ThreadFactoryBuilder(String pool) {
+        this.namePrefix = pool + "-thread-";
+    }
+
+
+    public static ThreadFactoryBuilder pool(String name) {
+        return new ThreadFactoryBuilder(name);
+    }
+
+    public ThreadFactoryBuilder lowPrio() {
+        prio = Thread.MIN_PRIORITY;
+        return this;
+    }
+
+    public ThreadFactoryBuilder daemon() {
+        daemon = true;
+        return this;
+    }
+
+    public ThreadFactory build() {
+        SecurityManager s = System.getSecurityManager();
+        final ThreadGroup group = (s != null) ? s.getThreadGroup() :
+                Thread.currentThread().getThreadGroup();
+
+        return new ThreadFactory() {
+            private final AtomicInteger threadNumber = new AtomicInteger(1);
+
+            @Override
+            public Thread newThread(Runnable r) {
+                Thread t = new Thread(group, r,
+                        namePrefix + threadNumber.getAndIncrement(),
+                        0);
+                t.setPriority(prio);
+                t.setDaemon(daemon);
+                return t;
+            }
+        };
+    }
+}

core/src/main/resources/nodes.txt

@@ -0,0 +1,8 @@
+[stream 1]
+
+dissem.ch:8444
+bootstrap8080.bitmessage.org:8080
+bootstrap8444.bitmessage.org:8444
+
+[stream 2]
+# none yet

core/src/test/java/ch/dissem/bitmessage/BitmessageContextTest.java

@@ -0,0 +1,315 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage;
+
+import ch.dissem.bitmessage.cryptography.bc.BouncyCryptography;
+import ch.dissem.bitmessage.entity.BitmessageAddress;
+import ch.dissem.bitmessage.entity.ObjectMessage;
+import ch.dissem.bitmessage.entity.Plaintext;
+import ch.dissem.bitmessage.entity.Plaintext.Type;
+import ch.dissem.bitmessage.entity.payload.ObjectType;
+import ch.dissem.bitmessage.entity.payload.Pubkey;
+import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
+import ch.dissem.bitmessage.ports.*;
+import ch.dissem.bitmessage.utils.MessageMatchers;
+import ch.dissem.bitmessage.utils.Singleton;
+import ch.dissem.bitmessage.utils.TTL;
+import ch.dissem.bitmessage.utils.TestUtils;
+import org.hamcrest.BaseMatcher;
+import org.hamcrest.Description;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.*;
+
+import static ch.dissem.bitmessage.entity.payload.ObjectType.*;
+import static ch.dissem.bitmessage.utils.MessageMatchers.object;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
+import static ch.dissem.bitmessage.utils.UnixTime.MINUTE;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+/**
+ * @author Christian Basler
+ */
+public class BitmessageContextTest {
+    private BitmessageContext ctx;
+    private BitmessageContext.Listener listener;
+
+    @Before
+    public void setUp() throws Exception {
+        Singleton.initialize(null);
+        listener = mock(BitmessageContext.Listener.class);
+        ctx = new BitmessageContext.Builder()
+                .addressRepo(mock(AddressRepository.class))
+                .cryptography(new BouncyCryptography())
+                .inventory(mock(Inventory.class))
+                .listener(listener)
+                .messageRepo(mock(MessageRepository.class))
+                .networkHandler(mock(NetworkHandler.class))
+                .nodeRegistry(mock(NodeRegistry.class))
+                .labeler(spy(new DefaultLabeler()))
+                .powRepo(spy(new ProofOfWorkRepository() {
+                    Map<InventoryVector, Item> items = new HashMap<>();
+
+                    @Override
+                    public Item getItem(byte[] initialHash) {
+                        return items.get(new InventoryVector(initialHash));
+                    }
+
+                    @Override
+                    public List<byte[]> getItems() {
+                        List<byte[]> result = new LinkedList<>();
+                        for (InventoryVector iv : items.keySet()) {
+                            result.add(iv.getHash());
+                        }
+                        return result;
+                    }
+
+                    @Override
+                    public void putObject(Item item) {
+                        items.put(new InventoryVector(cryptography().getInitialHash(item.object)), item);
+                    }
+
+                    @Override
+                    public void putObject(ObjectMessage object, long nonceTrialsPerByte, long extraBytes) {
+                        items.put(new InventoryVector(cryptography().getInitialHash(object)), new Item(object, nonceTrialsPerByte, extraBytes));
+                    }
+
+                    @Override
+                    public void removeObject(byte[] initialHash) {
+                        items.remove(initialHash);
+                    }
+                }))
+                .proofOfWorkEngine(spy(new ProofOfWorkEngine() {
+                    @Override
+                    public void calculateNonce(byte[] initialHash, byte[] target, Callback callback) {
+                        callback.onNonceCalculated(initialHash, new byte[8]);
+                    }
+                }))
+                .build();
+        TTL.msg(2 * MINUTE);
+    }
+
+    @Test
+    public void ensureContactIsSavedAndPubkeyRequested() {
+        BitmessageAddress contact = new BitmessageAddress("BM-opWQhvk9xtMFvQA2Kvetedpk8LkbraWHT");
+        ctx.addContact(contact);
+
+        verify(ctx.addresses(), times(2)).save(contact);
+        verify(ctx.internals().getProofOfWorkEngine())
+                .calculateNonce(any(byte[].class), any(byte[].class), any(ProofOfWorkEngine.Callback.class));
+    }
+
+    @Test
+    public void ensurePubkeyIsNotRequestedIfItExists() throws Exception {
+        ObjectMessage object = TestUtils.loadObjectMessage(2, "V2Pubkey.payload");
+        Pubkey pubkey = (Pubkey) object.getPayload();
+        BitmessageAddress contact = new BitmessageAddress("BM-opWQhvk9xtMFvQA2Kvetedpk8LkbraWHT");
+        contact.setPubkey(pubkey);
+
+        ctx.addContact(contact);
+
+        verify(ctx.addresses(), times(1)).save(contact);
+        verify(ctx.internals().getProofOfWorkEngine(), never())
+                .calculateNonce(any(byte[].class), any(byte[].class), any(ProofOfWorkEngine.Callback.class));
+    }
+
+    @Test
+    public void ensureV2PubkeyIsNotRequestedIfItExistsInInventory() throws Exception {
+        BitmessageAddress contact = new BitmessageAddress("BM-opWQhvk9xtMFvQA2Kvetedpk8LkbraWHT");
+        when(ctx.internals().getInventory().getObjects(anyLong(), anyLong(), any(ObjectType.class)))
+                .thenReturn(Collections.singletonList(
+                        TestUtils.loadObjectMessage(2, "V2Pubkey.payload")
+                ));
+
+        ctx.addContact(contact);
+
+        verify(ctx.addresses(), atLeastOnce()).save(contact);
+        verify(ctx.internals().getProofOfWorkEngine(), never())
+                .calculateNonce(any(byte[].class), any(byte[].class), any(ProofOfWorkEngine.Callback.class));
+    }
+
+    @Test
+    public void ensureV4PubkeyIsNotRequestedIfItExistsInInventory() throws Exception {
+        BitmessageAddress contact = new BitmessageAddress("BM-2cXxfcSetKnbHJX2Y85rSkaVpsdNUZ5q9h");
+        when(ctx.internals().getInventory().getObjects(anyLong(), anyLong(), any(ObjectType.class)))
+                .thenReturn(Collections.singletonList(
+                        TestUtils.loadObjectMessage(2, "V4Pubkey.payload")
+                ));
+        final BitmessageAddress stored = new BitmessageAddress(contact.getAddress());
+        stored.setAlias("Test");
+        when(ctx.addresses().getAddress(contact.getAddress())).thenReturn(stored);
+
+        ctx.addContact(contact);
+
+        verify(ctx.addresses(), atLeastOnce()).save(argThat(new BaseMatcher<BitmessageAddress>() {
+            @Override
+            public boolean matches(Object item) {
+                return item instanceof BitmessageAddress
+                        && ((BitmessageAddress) item).getPubkey() != null
+                        && stored.getAlias().equals(((BitmessageAddress) item).getAlias());
+            }
+
+            @Override
+            public void describeTo(Description description) {
+                description.appendText("pubkey must not be null and alias must be ").appendValue(stored.getAlias());
+            }
+        }));
+        verify(ctx.internals().getProofOfWorkEngine(), never())
+                .calculateNonce(any(byte[].class), any(byte[].class), any(ProofOfWorkEngine.Callback.class));
+    }
+
+    @Test
+    public void ensureSubscriptionIsAddedAndExistingBroadcastsRetrieved() throws Exception {
+        BitmessageAddress address = new BitmessageAddress("BM-2D9Vc5rFxxR5vTi53T9gkLfemViHRMVLQZ");
+
+        List<ObjectMessage> objects = new LinkedList<>();
+        objects.add(TestUtils.loadObjectMessage(4, "V4Broadcast.payload"));
+        objects.add(TestUtils.loadObjectMessage(5, "V5Broadcast.payload"));
+        when(ctx.internals().getInventory().getObjects(eq(address.getStream()), anyLong(), any(ObjectType.class)))
+                .thenReturn(objects);
+        when(ctx.addresses().getSubscriptions(anyLong())).thenReturn(Collections.singletonList(address));
+
+        ctx.addSubscribtion(address);
+
+        verify(ctx.addresses(), atLeastOnce()).save(address);
+        assertThat(address.isSubscribed(), is(true));
+        verify(ctx.internals().getInventory()).getObjects(eq(address.getStream()), anyLong(), any(ObjectType.class));
+        verify(listener).receive(any(Plaintext.class));
+    }
+
+    @Test
+    public void ensureIdentityIsCreated() {
+        assertThat(ctx.createIdentity(false), notNullValue());
+    }
+
+    @Test
+    public void ensureMessageIsSent() throws Exception {
+        ctx.send(TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8"), TestUtils.loadContact(),
+                "Subject", "Message");
+        assertEquals(2, ctx.internals().getProofOfWorkRepository().getItems().size());
+        verify(ctx.internals().getProofOfWorkRepository(), timeout(10000).atLeastOnce())
+                .putObject(object(MSG), eq(1000L), eq(1000L));
+        verify(ctx.messages(), timeout(10000).atLeastOnce()).save(MessageMatchers.plaintext(Type.MSG));
+    }
+
+    @Test
+    public void ensurePubkeyIsRequestedIfItIsMissing() throws Exception {
+        ctx.send(TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8"),
+                new BitmessageAddress("BM-opWQhvk9xtMFvQA2Kvetedpk8LkbraWHT"),
+                "Subject", "Message");
+        verify(ctx.internals().getProofOfWorkRepository(), timeout(10000).atLeastOnce())
+                .putObject(object(GET_PUBKEY), eq(1000L), eq(1000L));
+        verify(ctx.messages(), timeout(10000).atLeastOnce()).save(MessageMatchers.plaintext(Type.MSG));
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void ensureSenderMustBeIdentity() {
+        ctx.send(new BitmessageAddress("BM-opWQhvk9xtMFvQA2Kvetedpk8LkbraWHT"),
+                new BitmessageAddress("BM-opWQhvk9xtMFvQA2Kvetedpk8LkbraWHT"),
+                "Subject", "Message");
+    }
+
+    @Test
+    public void ensureBroadcastIsSent() throws Exception {
+        ctx.broadcast(TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8"),
+                "Subject", "Message");
+        verify(ctx.internals().getProofOfWorkRepository(), timeout(10000).atLeastOnce())
+                .putObject(object(BROADCAST), eq(1000L), eq(1000L));
+        verify(ctx.internals().getProofOfWorkEngine())
+                .calculateNonce(any(byte[].class), any(byte[].class), any(ProofOfWorkEngine.Callback.class));
+        verify(ctx.messages(), timeout(10000).atLeastOnce())
+                .save(MessageMatchers.plaintext(Type.BROADCAST));
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void ensureSenderWithoutPrivateKeyThrowsException() {
+        Plaintext msg = new Plaintext.Builder(Type.BROADCAST)
+                .from(new BitmessageAddress("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8"))
+                .message("Subject", "Message")
+                .build();
+        ctx.send(msg);
+    }
+
+    @Test
+    public void ensureChanIsJoined() {
+        String chanAddress = "BM-2cW67GEKkHGonXKZLCzouLLxnLym3azS8r";
+        BitmessageAddress chan = ctx.joinChan("general", chanAddress);
+        assertNotNull(chan);
+        assertEquals(chan.getAddress(), chanAddress);
+        assertTrue(chan.isChan());
+    }
+
+    @Test
+    public void ensureDeterministicAddressesAreCreated() {
+        final int expected_size = 8;
+        List<BitmessageAddress> addresses = ctx.createDeterministicAddresses("test", expected_size, 4, 1, false);
+        assertEquals(expected_size, addresses.size());
+        Set<String> expected = new HashSet<>(expected_size);
+        expected.add("BM-2cWFkyuXXFw6d393RGnin2RpSXj8wxtt6F");
+        expected.add("BM-2cX8TF9vuQZEWvT7UrEeq1HN9dgiSUPLEN");
+        expected.add("BM-2cUzX8f9CKUU7L8NeB8GExZvf54PrcXq1S");
+        expected.add("BM-2cU7MAoQd7KE8SPF7AKFPpoEZKjk86KRqE");
+        expected.add("BM-2cVm8ByVBacc2DVhdTNs6rmy5ZQK6DUsrt");
+        expected.add("BM-2cW2af1vB6kWon2WkygDHqGwfcpfAFm2Jk");
+        expected.add("BM-2cWdWD7UtUN4gWChgNX9pvyvNPjUZvU8BT");
+        expected.add("BM-2cXkYgYcUrv4fGxSHzyEScW955Cc8sDteo");
+        for (BitmessageAddress a : addresses) {
+            assertTrue(expected.contains(a.getAddress()));
+            expected.remove(a.getAddress());
+        }
+    }
+
+    @Test
+    public void ensureShortDeterministicAddressesAreCreated() {
+        final int expected_size = 1;
+        List<BitmessageAddress> addresses = ctx.createDeterministicAddresses("test", expected_size, 4, 1, true);
+        assertEquals(expected_size, addresses.size());
+        Set<String> expected = new HashSet<>(expected_size);
+        expected.add("BM-NBGyBAEp6VnBkFWKpzUSgxuTqVdWPi78");
+        for (BitmessageAddress a : addresses) {
+            assertTrue(expected.contains(a.getAddress()));
+            expected.remove(a.getAddress());
+        }
+    }
+
+    @Test
+    public void ensureChanIsCreated() {
+        BitmessageAddress chan = ctx.createChan("test");
+        assertNotNull(chan);
+        assertEquals(chan.getVersion(), Pubkey.LATEST_VERSION);
+        assertTrue(chan.isChan());
+    }
+
+    @Test
+    public void ensureUnacknowledgedMessageIsResent() throws Exception {
+        Plaintext plaintext = new Plaintext.Builder(Type.MSG)
+                .ttl(1)
+                .message("subject", "message")
+                .from(TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8"))
+                .to(TestUtils.loadContact())
+                .build();
+        assertTrue(plaintext.getTo().has(Pubkey.Feature.DOES_ACK));
+        when(ctx.messages().findMessagesToResend()).thenReturn(Collections.singletonList(plaintext));
+        when(ctx.messages().getMessage(any(byte[].class))).thenReturn(plaintext);
+        ctx.resendUnacknowledgedMessages();
+        verify(ctx.labeler(), timeout(1000).times(1)).markAsSent(eq(plaintext));
+    }
+}

core/src/test/java/ch/dissem/bitmessage/DecryptionTest.java

@@ -21,6 +21,7 @@ import ch.dissem.bitmessage.entity.ObjectMessage;
 import ch.dissem.bitmessage.entity.payload.V4Broadcast;
 import ch.dissem.bitmessage.entity.payload.V5Broadcast;
 import ch.dissem.bitmessage.exception.DecryptionFailedException;
+import ch.dissem.bitmessage.utils.TestBase;
 import ch.dissem.bitmessage.utils.TestUtils;
 import org.junit.Test;
 
@@ -29,7 +30,7 @@ import java.io.IOException;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
-public class DecryptionTest {
+public class DecryptionTest extends TestBase {
     @Test
     public void ensureV4BroadcastIsDecryptedCorrectly() throws IOException, DecryptionFailedException {
         BitmessageAddress address = new BitmessageAddress("BM-2D9Vc5rFxxR5vTi53T9gkLfemViHRMVLQZ");

core/src/test/java/ch/dissem/bitmessage/DefaultMessageListenerTest.java

@@ -0,0 +1,157 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage;
+
+import ch.dissem.bitmessage.cryptography.bc.BouncyCryptography;
+import ch.dissem.bitmessage.entity.BitmessageAddress;
+import ch.dissem.bitmessage.entity.ObjectMessage;
+import ch.dissem.bitmessage.entity.Plaintext;
+import ch.dissem.bitmessage.entity.payload.Broadcast;
+import ch.dissem.bitmessage.entity.payload.GetPubkey;
+import ch.dissem.bitmessage.entity.payload.Msg;
+import ch.dissem.bitmessage.factory.Factory;
+import ch.dissem.bitmessage.ports.*;
+import ch.dissem.bitmessage.utils.Singleton;
+import ch.dissem.bitmessage.utils.TestBase;
+import ch.dissem.bitmessage.utils.TestUtils;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.Collections;
+
+import static ch.dissem.bitmessage.entity.Plaintext.Status.PUBKEY_REQUESTED;
+import static ch.dissem.bitmessage.entity.Plaintext.Type.BROADCAST;
+import static ch.dissem.bitmessage.entity.Plaintext.Type.MSG;
+import static ch.dissem.bitmessage.utils.MessageMatchers.plaintext;
+import static org.mockito.Mockito.*;
+
+/**
+ * @author Christian Basler
+ */
+public class DefaultMessageListenerTest extends TestBase {
+    @Mock
+    private AddressRepository addressRepo;
+    @Mock
+    private MessageRepository messageRepo;
+    @Mock
+    private Inventory inventory;
+    @Mock
+    private NetworkHandler networkHandler;
+
+    private InternalContext ctx;
+    private DefaultMessageListener listener;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        ctx = mock(InternalContext.class);
+        Singleton.initialize(new BouncyCryptography());
+        when(ctx.getAddressRepository()).thenReturn(addressRepo);
+        when(ctx.getMessageRepository()).thenReturn(messageRepo);
+        when(ctx.getInventory()).thenReturn(inventory);
+        when(ctx.getNetworkHandler()).thenReturn(networkHandler);
+        when(ctx.getLabeler()).thenReturn(mock(Labeler.class));
+
+        listener = new DefaultMessageListener(mock(Labeler.class), mock(BitmessageContext.Listener.class));
+        when(ctx.getNetworkListener()).thenReturn(listener);
+        listener.setContext(ctx);
+    }
+
+    @Test
+    public void ensurePubkeyIsSentOnRequest() throws Exception {
+        BitmessageAddress identity = TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8");
+        when(addressRepo.findIdentity(any(byte[].class)))
+                .thenReturn(identity);
+        listener.receive(new ObjectMessage.Builder()
+                .stream(2)
+                .payload(new GetPubkey(new BitmessageAddress("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8")))
+                .build());
+        verify(ctx).sendPubkey(eq(identity), eq(2L));
+    }
+
+    @Test
+    public void ensureIncomingPubkeyIsAddedToContact() throws Exception {
+        BitmessageAddress identity = TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8");
+        BitmessageAddress contact = new BitmessageAddress(identity.getAddress());
+        when(addressRepo.findContact(any(byte[].class)))
+                .thenReturn(contact);
+        when(messageRepo.findMessages(eq(PUBKEY_REQUESTED), eq(contact)))
+                .thenReturn(Collections.singletonList(
+                        new Plaintext.Builder(MSG).from(identity).to(contact).message("S", "T").build()
+                ));
+
+        ObjectMessage objectMessage = new ObjectMessage.Builder()
+                .stream(2)
+                .payload(identity.getPubkey())
+                .build();
+        objectMessage.sign(identity.getPrivateKey());
+        objectMessage.encrypt(Singleton.cryptography().createPublicKey(identity.getPublicDecryptionKey()));
+        listener.receive(objectMessage);
+
+        verify(addressRepo).save(any(BitmessageAddress.class));
+    }
+
+    @Test
+    public void ensureIncomingMessageIsSaved() throws Exception {
+        BitmessageAddress identity = TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8");
+        BitmessageAddress contact = new BitmessageAddress(identity.getAddress());
+        contact.setPubkey(identity.getPubkey());
+
+        when(addressRepo.getIdentities()).thenReturn(Collections.singletonList(identity));
+
+        ObjectMessage objectMessage = new ObjectMessage.Builder()
+                .stream(2)
+                .payload(new Msg(new Plaintext.Builder(MSG)
+                        .from(identity)
+                        .to(contact)
+                        .message("S", "T")
+                        .build()))
+                .nonce(new byte[8])
+                .build();
+        objectMessage.sign(identity.getPrivateKey());
+        objectMessage.encrypt(identity.getPubkey());
+
+        listener.receive(objectMessage);
+
+        verify(messageRepo, atLeastOnce()).save(plaintext(MSG));
+    }
+
+    @Test
+    public void ensureIncomingBroadcastIsSaved() throws Exception {
+        BitmessageAddress identity = TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8");
+
+        when(addressRepo.getSubscriptions(anyLong())).thenReturn(Collections.singletonList(identity));
+
+        Broadcast broadcast = Factory.getBroadcast(new Plaintext.Builder(BROADCAST)
+                .from(identity)
+                .message("S", "T")
+                .build());
+        ObjectMessage objectMessage = new ObjectMessage.Builder()
+                .stream(2)
+                .payload(broadcast)
+                .nonce(new byte[8])
+                .build();
+        objectMessage.sign(identity.getPrivateKey());
+        broadcast.encrypt();
+
+        listener.receive(objectMessage);
+
+        verify(messageRepo, atLeastOnce()).save(plaintext(BROADCAST));
+    }
+}

core/src/test/java/ch/dissem/bitmessage/EncryptionTest.java

@@ -24,25 +24,25 @@ import ch.dissem.bitmessage.entity.payload.GenericPayload;
 import ch.dissem.bitmessage.entity.payload.Msg;
 import ch.dissem.bitmessage.entity.valueobject.PrivateKey;
 import ch.dissem.bitmessage.exception.DecryptionFailedException;
-import ch.dissem.bitmessage.utils.Security;
+import ch.dissem.bitmessage.utils.TestBase;
 import ch.dissem.bitmessage.utils.TestUtils;
 import org.junit.Test;
 
 import java.io.IOException;
 
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
 
-public class EncryptionTest {
+public class EncryptionTest extends TestBase {
     @Test
     public void ensureDecryptedDataIsSameAsBeforeEncryption() throws IOException, DecryptionFailedException {
-        GenericPayload before = new GenericPayload(0, 1, Security.randomBytes(100));
+        GenericPayload before = new GenericPayload(0, 1, cryptography().randomBytes(100));
 
         PrivateKey privateKey = new PrivateKey(false, 1, 1000, 1000);
         CryptoBox cryptoBox = new CryptoBox(before, privateKey.getPubkey().getEncryptionKey());
 
-        GenericPayload after = GenericPayload.read(0, cryptoBox.decrypt(privateKey.getPrivateEncryptionKey()), 1, 100);
+        GenericPayload after = GenericPayload.read(0, 1, cryptoBox.decrypt(privateKey.getPrivateEncryptionKey()), 100);
 
         assertEquals(before, after);
     }

core/src/test/java/ch/dissem/bitmessage/ProofOfWorkServiceTest.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2016 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage;
+
+import ch.dissem.bitmessage.cryptography.bc.BouncyCryptography;
+import ch.dissem.bitmessage.entity.BitmessageAddress;
+import ch.dissem.bitmessage.entity.ObjectMessage;
+import ch.dissem.bitmessage.entity.Plaintext;
+import ch.dissem.bitmessage.entity.payload.Msg;
+import ch.dissem.bitmessage.ports.*;
+import ch.dissem.bitmessage.utils.Singleton;
+import ch.dissem.bitmessage.utils.TestUtils;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.Arrays;
+
+import static ch.dissem.bitmessage.entity.Plaintext.Type.MSG;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertThat;
+import static org.mockito.Mockito.*;
+
+/**
+ * @author Christian Basler
+ */
+public class ProofOfWorkServiceTest {
+    private ProofOfWorkService proofOfWorkService;
+
+    private Cryptography cryptography;
+    @Mock
+    private InternalContext ctx;
+    @Mock
+    private ProofOfWorkRepository proofOfWorkRepo;
+    @Mock
+    private Inventory inventory;
+    @Mock
+    private NetworkHandler networkHandler;
+    @Mock
+    private MessageRepository messageRepo;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        cryptography = spy(new BouncyCryptography());
+        Singleton.initialize(cryptography);
+
+        ctx = mock(InternalContext.class);
+        when(ctx.getProofOfWorkRepository()).thenReturn(proofOfWorkRepo);
+        when(ctx.getInventory()).thenReturn(inventory);
+        when(ctx.getNetworkHandler()).thenReturn(networkHandler);
+        when(ctx.getMessageRepository()).thenReturn(messageRepo);
+        when(ctx.getLabeler()).thenReturn(mock(Labeler.class));
+        when(ctx.getNetworkListener()).thenReturn(mock(NetworkHandler.MessageListener.class));
+
+        proofOfWorkService = new ProofOfWorkService();
+        proofOfWorkService.setContext(ctx);
+    }
+
+    @Test
+    public void ensureMissingProofOfWorkIsDone() {
+        when(proofOfWorkRepo.getItems()).thenReturn(Arrays.asList(new byte[64]));
+        when(proofOfWorkRepo.getItem(any(byte[].class))).thenReturn(new ProofOfWorkRepository.Item(null, 1001, 1002));
+        doNothing().when(cryptography).doProofOfWork(any(ObjectMessage.class), anyLong(), anyLong(), any(ProofOfWorkEngine.Callback.class));
+
+        proofOfWorkService.doMissingProofOfWork(10);
+
+        verify(cryptography, timeout(1000)).doProofOfWork((ObjectMessage) isNull(), eq(1001L), eq(1002L),
+            any(ProofOfWorkEngine.Callback.class));
+    }
+
+    @Test
+    public void ensureCalculatedNonceIsStored() throws Exception {
+        BitmessageAddress identity = TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8");
+        BitmessageAddress address = TestUtils.loadContact();
+        Plaintext plaintext = new Plaintext.Builder(MSG).from(identity).to(address).message("", "").build();
+        ObjectMessage object = new ObjectMessage.Builder()
+            .payload(new Msg(plaintext))
+            .build();
+        object.sign(identity.getPrivateKey());
+        object.encrypt(address.getPubkey());
+        byte[] initialHash = new byte[64];
+        byte[] nonce = new byte[]{1, 2, 3, 4, 5, 6, 7, 8};
+
+        when(proofOfWorkRepo.getItem(initialHash)).thenReturn(new ProofOfWorkRepository.Item(object, 1001, 1002));
+        when(messageRepo.getMessage(initialHash)).thenReturn(plaintext);
+
+        proofOfWorkService.onNonceCalculated(initialHash, nonce);
+
+        verify(proofOfWorkRepo).removeObject(eq(initialHash));
+        verify(inventory).storeObject(eq(object));
+        verify(networkHandler).offer(eq(object.getInventoryVector()));
+        assertThat(plaintext.getInventoryVector(), equalTo(object.getInventoryVector()));
+    }
+}

core/src/test/java/ch/dissem/bitmessage/SignatureTest.java

@@ -22,18 +22,17 @@ import ch.dissem.bitmessage.entity.Plaintext;
 import ch.dissem.bitmessage.entity.payload.Msg;
 import ch.dissem.bitmessage.entity.payload.ObjectType;
 import ch.dissem.bitmessage.entity.payload.Pubkey;
-import ch.dissem.bitmessage.entity.payload.V4Pubkey;
 import ch.dissem.bitmessage.entity.valueobject.PrivateKey;
 import ch.dissem.bitmessage.exception.DecryptionFailedException;
+import ch.dissem.bitmessage.utils.TestBase;
 import ch.dissem.bitmessage.utils.TestUtils;
 import org.junit.Test;
 
 import java.io.IOException;
-import java.util.Date;
 
 import static org.junit.Assert.*;
 
-public class SignatureTest {
+public class SignatureTest extends TestBase {
     @Test
     public void ensureValidationWorks() throws IOException {
         ObjectMessage object = TestUtils.loadObjectMessage(3, "V3Pubkey.payload");

core/src/test/java/ch/dissem/bitmessage/entity/BitmessageAddressTest.java

@@ -27,9 +27,18 @@ import java.io.IOException;
 import java.util.Arrays;
 
 import static ch.dissem.bitmessage.entity.payload.Pubkey.Feature.DOES_ACK;
+import static ch.dissem.bitmessage.entity.payload.Pubkey.Feature.INCLUDE_DESTINATION;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
 import static org.junit.Assert.*;
 
-public class BitmessageAddressTest {
+public class BitmessageAddressTest extends TestBase {
+    @Test
+    public void ensureFeatureFlagIsCalculatedCorrectly() {
+        assertEquals(1, Pubkey.Feature.bitfield(DOES_ACK));
+        assertEquals(2, Pubkey.Feature.bitfield(INCLUDE_DESTINATION));
+        assertEquals(3, Pubkey.Feature.bitfield(DOES_ACK, INCLUDE_DESTINATION));
+    }
+
     @Test
     public void ensureBase58DecodesCorrectly() {
         assertHexEquals("800C28FCA386C7A227600B2FE50B7CAE11EC86D3BF1FBE471BE89827E19D72AA1D507A5B8D",
@@ -54,44 +63,59 @@ public class BitmessageAddressTest {
     }
 
     @Test
-    public void testCreateAddress() {
+    public void ensureIdentityCanBeCreated() {
         BitmessageAddress address = new BitmessageAddress(new PrivateKey(false, 1, 1000, 1000, DOES_ACK));
         assertNotNull(address.getPubkey());
+        assertTrue(address.has(DOES_ACK));
     }
 
     @Test
-    public void testV2PubkeyImport() throws IOException {
+    public void ensureV2PubkeyCanBeImported() throws IOException {
         ObjectMessage object = TestUtils.loadObjectMessage(2, "V2Pubkey.payload");
         Pubkey pubkey = (Pubkey) object.getPayload();
         BitmessageAddress address = new BitmessageAddress("BM-opWQhvk9xtMFvQA2Kvetedpk8LkbraWHT");
-        address.setPubkey(pubkey);
+        try {
+            address.setPubkey(pubkey);
+        } catch (Exception e) {
+            fail(e.getMessage());
+        }
     }
 
     @Test
-    public void testV3PubkeyImport() throws IOException {
+    public void ensureV3PubkeyCanBeImported() throws IOException {
         BitmessageAddress address = new BitmessageAddress("BM-2D9Vc5rFxxR5vTi53T9gkLfemViHRMVLQZ");
         assertArrayEquals(Bytes.fromHex("007402be6e76c3cb87caa946d0c003a3d4d8e1d5"), address.getRipe());
 
         ObjectMessage object = TestUtils.loadObjectMessage(3, "V3Pubkey.payload");
         Pubkey pubkey = (Pubkey) object.getPayload();
         assertTrue(object.isSignatureValid(pubkey));
-        address.setPubkey(pubkey);
+        try {
+            address.setPubkey(pubkey);
+        } catch (Exception e) {
+            fail(e.getMessage());
+        }
 
         assertArrayEquals(Bytes.fromHex("007402be6e76c3cb87caa946d0c003a3d4d8e1d5"), pubkey.getRipe());
+        assertTrue(address.has(DOES_ACK));
     }
 
     @Test
-    public void testV4PubkeyImport() throws IOException, DecryptionFailedException {
+    public void ensureV4PubkeyCanBeImported() throws IOException, DecryptionFailedException {
         BitmessageAddress address = new BitmessageAddress("BM-2cXxfcSetKnbHJX2Y85rSkaVpsdNUZ5q9h");
         ObjectMessage object = TestUtils.loadObjectMessage(4, "V4Pubkey.payload");
         object.decrypt(address.getPublicDecryptionKey());
         V4Pubkey pubkey = (V4Pubkey) object.getPayload();
         assertTrue(object.isSignatureValid(pubkey));
-        address.setPubkey(pubkey);
+        try {
+            address.setPubkey(pubkey);
+        } catch (Exception e) {
+            fail(e.getMessage());
+        }
+        assertTrue(address.has(DOES_ACK));
     }
 
     @Test
-    public void testV3AddressImport() throws IOException {
+    public void ensureV3IdentityCanBeImported() throws IOException {
         String address_string = "BM-2DAjcCFrqFrp88FUxExhJ9kPqHdunQmiyn";
         assertEquals(3, new BitmessageAddress(address_string).getVersion());
         assertEquals(1, new BitmessageAddress(address_string).getStream());
@@ -102,14 +126,22 @@ public class BitmessageAddressTest {
         System.out.println("\n\n" + Strings.hex(privsigningkey) + "\n\n");
 
         BitmessageAddress address = new BitmessageAddress(new PrivateKey(privsigningkey, privencryptionkey,
-                Security.createPubkey(3, 1, privsigningkey, privencryptionkey, 320, 14000)));
+                cryptography().createPubkey(3, 1, privsigningkey, privencryptionkey, 320, 14000)));
         assertEquals(address_string, address.getAddress());
     }
 
     @Test
-    public void testGetSecret() throws IOException {
-        assertHexEquals("0C28FCA386C7A227600B2FE50B7CAE11EC86D3BF1FBE471BE89827E19D72AA1D",
-                getSecret("5HueCGU8rMjxEXxiPuD5BDku4MkFqeZyd4dZ1jvhTVqvbTLvyTJ"));
+    public void ensureV4IdentityCanBeImported() throws IOException {
+        assertEquals(4, new BitmessageAddress("BM-2cV5f9EpzaYARxtoruSpa6pDoucSf9ZNke").getVersion());
+        byte[] privsigningkey = getSecret("5KMWqfCyJZGFgW6QrnPJ6L9Gatz25B51y7ErgqNr1nXUVbtZbdU");
+        byte[] privencryptionkey = getSecret("5JXXWEuhHQEPk414SzEZk1PHDRi8kCuZd895J7EnKeQSahJPxGz");
+        BitmessageAddress address = new BitmessageAddress(new PrivateKey(privsigningkey, privencryptionkey,
+                cryptography().createPubkey(4, 1, privsigningkey, privencryptionkey, 320, 14000)));
+        assertEquals("BM-2cV5f9EpzaYARxtoruSpa6pDoucSf9ZNke", address.getAddress());
+    }
+
+    private void assertHexEquals(String hex, byte[] bytes) {
+        assertEquals(hex.toLowerCase(), Strings.hex(bytes).toString().toLowerCase());
     }
 
     private byte[] getSecret(String walletImportFormat) throws IOException {
@@ -119,24 +151,10 @@ public class BitmessageAddressTest {
         if (bytes.length != 37)
             throw new IOException("Unknown format: 37 bytes expected, but secret " + walletImportFormat + " was " + bytes.length + " long");
 
-        byte[] hash = Security.doubleSha256(bytes, 33);
+        byte[] hash = cryptography().doubleSha256(bytes, 33);
         for (int i = 0; i < 4; i++) {
             if (hash[i] != bytes[33 + i]) throw new IOException("Hash check failed for secret " + walletImportFormat);
         }
         return Arrays.copyOfRange(bytes, 1, 33);
     }
-
-    @Test
-    public void testV4AddressImport() throws IOException {
-        assertEquals(4, new BitmessageAddress("BM-2cV5f9EpzaYARxtoruSpa6pDoucSf9ZNke").getVersion());
-        byte[] privsigningkey = getSecret("5KMWqfCyJZGFgW6QrnPJ6L9Gatz25B51y7ErgqNr1nXUVbtZbdU");
-        byte[] privencryptionkey = getSecret("5JXXWEuhHQEPk414SzEZk1PHDRi8kCuZd895J7EnKeQSahJPxGz");
-        BitmessageAddress address = new BitmessageAddress(new PrivateKey(privsigningkey, privencryptionkey,
-                Security.createPubkey(4, 1, privsigningkey, privencryptionkey, 320, 14000)));
-        assertEquals("BM-2cV5f9EpzaYARxtoruSpa6pDoucSf9ZNke", address.getAddress());
-    }
-
-    private void assertHexEquals(String hex, byte[] bytes) {
-        assertEquals(hex.toLowerCase(), Strings.hex(bytes).toString().toLowerCase());
-    }
 }

core/src/test/java/ch/dissem/bitmessage/entity/SerializationTest.java

@@ -17,21 +17,23 @@
 package ch.dissem.bitmessage.entity;
 
 import ch.dissem.bitmessage.entity.payload.*;
-import ch.dissem.bitmessage.exception.DecryptionFailedException;
+import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
+import ch.dissem.bitmessage.entity.valueobject.Label;
 import ch.dissem.bitmessage.factory.Factory;
+import ch.dissem.bitmessage.utils.TestBase;
 import ch.dissem.bitmessage.utils.TestUtils;
 import org.junit.Test;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
+import java.io.*;
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.Collections;
 
 import static ch.dissem.bitmessage.entity.Plaintext.Type.MSG;
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
+import static org.junit.Assert.*;
 
-public class SerializationTest {
+public class SerializationTest extends TestBase {
     @Test
     public void ensureGetPubkeyIsDeserializedAndSerializedCorrectly() throws IOException {
         doTest("V2GetPubkey.payload", 2, GetPubkey.class);
@@ -75,28 +77,96 @@ public class SerializationTest {
     }
 
     @Test
-    public void ensurePlaintextIsSerializedAndDeserializedCorrectly() throws IOException, DecryptionFailedException {
+    public void ensurePlaintextIsSerializedAndDeserializedCorrectly() throws Exception {
         Plaintext p1 = new Plaintext.Builder(MSG)
                 .from(TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8"))
                 .to(TestUtils.loadContact())
                 .message("Subject", "Message")
-                .ack("ack".getBytes())
+                .ackData("ackMessage".getBytes())
                 .signature(new byte[0])
                 .build();
         ByteArrayOutputStream out = new ByteArrayOutputStream();
         p1.write(out);
         ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
         Plaintext p2 = Plaintext.read(MSG, in);
+
+        // Received is automatically set on deserialization, so we'll need to set it to 0
+        Field received = Plaintext.class.getDeclaredField("received");
+        received.setAccessible(true);
+        received.set(p2, 0L);
+
         assertEquals(p1, p2);
     }
 
+    @Test
+    public void ensurePlaintextWithAckMessageIsSerializedAndDeserializedCorrectly() throws Exception {
+        Plaintext p1 = new Plaintext.Builder(MSG)
+                .from(TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8"))
+                .to(TestUtils.loadContact())
+                .message("Subject", "Message")
+                .ackData("ackMessage".getBytes())
+                .signature(new byte[0])
+                .build();
+        ObjectMessage ackMessage1 = p1.getAckMessage();
+        assertNotNull(ackMessage1);
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        p1.write(out);
+        ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
+        Plaintext p2 = Plaintext.read(MSG, in);
+
+        // Received is automatically set on deserialization, so we'll need to set it to 0
+        Field received = Plaintext.class.getDeclaredField("received");
+        received.setAccessible(true);
+        received.set(p2, 0L);
+
+        assertEquals(p1, p2);
+        assertEquals(ackMessage1, p2.getAckMessage());
+    }
+
+    @Test
+    public void ensureNetworkMessageIsSerializedAndDeserializedCorrectly() throws Exception {
+        ArrayList<InventoryVector> ivs = new ArrayList<>(50000);
+        for (int i = 0; i < 50000; i++) {
+            ivs.add(new InventoryVector(cryptography().randomBytes(32)));
+        }
+
+        Inv inv = new Inv.Builder().inventory(ivs).build();
+        NetworkMessage before = new NetworkMessage(inv);
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        before.write(out);
+
+        NetworkMessage after = Factory.getNetworkMessage(3, new ByteArrayInputStream(out.toByteArray()));
+        assertNotNull(after);
+        Inv invAfter = (Inv) after.getPayload();
+        assertEquals(ivs, invAfter.getInventory());
+    }
+
     private void doTest(String resourceName, int version, Class<?> expectedPayloadType) throws IOException {
         byte[] data = TestUtils.getBytes(resourceName);
         InputStream in = new ByteArrayInputStream(data);
         ObjectMessage object = Factory.getObjectMessage(version, in, data.length);
         ByteArrayOutputStream out = new ByteArrayOutputStream();
+        assertNotNull(object);
         object.write(out);
         assertArrayEquals(data, out.toByteArray());
         assertEquals(expectedPayloadType.getCanonicalName(), object.getPayload().getClass().getCanonicalName());
     }
+
+    @Test
+    public void ensureSystemSerializationWorks() throws Exception {
+        Plaintext plaintext = new Plaintext.Builder(MSG)
+                .from(TestUtils.loadContact())
+                .to(TestUtils.loadIdentity("BM-2cSqjfJ8xK6UUn5Rw3RpdGQ9RsDkBhWnS8"))
+                .labels(Collections.singletonList(new Label("Test", Label.Type.INBOX, 0)))
+                .message("Test", "Test Test.\nTest")
+                .build();
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        ObjectOutputStream oos = new ObjectOutputStream(out);
+        oos.writeObject(plaintext);
+
+        ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
+        ObjectInputStream ois = new ObjectInputStream(in);
+        assertEquals(plaintext, ois.readObject());
+    }
 }

core/src/test/java/ch/dissem/bitmessage/ports/ProofOfWorkEngineTest.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2015 Christian Basler
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ch.dissem.bitmessage.ports;
+
+import ch.dissem.bitmessage.utils.Bytes;
+import ch.dissem.bitmessage.utils.CallbackWaiter;
+import ch.dissem.bitmessage.utils.TestBase;
+import org.junit.Test;
+
+import static ch.dissem.bitmessage.utils.Singleton.cryptography;
+import static org.junit.Assert.assertTrue;
+
+public class ProofOfWorkEngineTest extends TestBase {
+    @Test(timeout = 90_000)
+    public void testSimplePOWEngine() throws InterruptedException {
+        testPOW(new SimplePOWEngine());
+    }
+
+    @Test(timeout = 90_000)
+    public void testThreadedPOWEngine() throws InterruptedException {
+        testPOW(new MultiThreadedPOWEngine());
+    }
+
+    private void testPOW(ProofOfWorkEngine engine) throws InterruptedException {
+        byte[] initialHash = cryptography().sha512(new byte[]{1, 3, 6, 4});
+        byte[] target = {0, 0, 0, -1, -1, -1, -1, -1};
+
+        final CallbackWaiter<byte[]> waiter1 = new CallbackWaiter<>();
+        engine.calculateNonce(initialHash, target,
+                new ProofOfWorkEngine.Callback() {
+                    @Override
+                    public void onNonceCalculated(byte[] initialHash, byte[] nonce) {
+                        waiter1.setValue(nonce);
+                    }
+                });
+        byte[] nonce = waiter1.waitForValue();
+        System.out.println("Calculating nonce took " + waiter1.getTime() + "ms");
+        assertTrue(Bytes.lt(cryptography().doubleSha512(nonce, initialHash), target, 8));
+
+        // Let's add a second (shorter) run to find possible multi threading issues
+        byte[] initialHash2 = cryptography().sha512(new byte[]{1, 3, 6, 5});
+        byte[] target2 = {0, 0, -1, -1, -1, -1, -1, -1};
+
+        final CallbackWaiter<byte[]> waiter2 = new CallbackWaiter<>();
+        engine.calculateNonce(initialHash2, target2,
+                new ProofOfWorkEngine.Callback() {
+                    @Override
+                    public void onNonceCalculated(byte[] initialHash, byte[] nonce) {
+                        waiter2.setValue(nonce);
+                    }
+                });
+        byte[] nonce2 = waiter2.waitForValue();
+        System.out.println("Calculating nonce took " + waiter2.getTime() + "ms");
+        assertTrue(Bytes.lt(cryptography().doubleSha512(nonce2, initialHash2), target2, 8));
+        assertTrue("Second nonce must be quicker to find", waiter1.getTime() > waiter2.getTime());
+    }
+
+}

core/src/test/java/ch/dissem/bitmessage/utils/BytesTest.java

@@ -16,6 +16,7 @@
 
 package ch.dissem.bitmessage.utils;
 
+import org.junit.Ignore;
 import org.junit.Test;
 
 import java.io.IOException;
@@ -25,16 +26,13 @@ import java.util.Random;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 
-/**
- * Created by chris on 10.04.15.
- */
 public class BytesTest {
     public static final Random rnd = new Random();
 
     @Test
     public void ensureExpandsCorrectly() {
         byte[] source = {1};
-        byte[] expected = {0,1};
+        byte[] expected = {0, 1};
         assertArrayEquals(expected, Bytes.expand(source, 2));
     }
 
@@ -56,6 +54,24 @@ public class BytesTest {
         }
     }
 
+    /**
+     * This test is used to compare different implementations of the single byte lt comparison. It an safely be ignored.
+     */
+    @Test
+    @Ignore
+    public void testLowerThanSingleByte() {
+        byte[] a = new byte[1];
+        byte[] b = new byte[1];
+        for (int i = 0; i < 255; i++) {
+            for (int j = 0; j < 255; j++) {
+                System.out.println("a = " + i + "\tb = " + j);
+                a[0] = (byte) i;
+                b[0] = (byte) j;
+                assertEquals(i < j, Bytes.lt(a, b));
+            }
+        }
+    }
+
     @Test
     public void testLowerThan() {
         for (int i = 0; i < 1000; i++) {