Added some POW code, it probably doesn't work yet

(takes very long and uses lots of battery, but I didn't get a result yet)

domain/build.gradle

@@ -9,5 +9,6 @@ repositories {
 
 dependencies {
     compile 'org.slf4j:slf4j-api:1.7.12'
+    compile 'org.bouncycastle:bcprov-jdk15on:1.52'
     testCompile group: 'junit', name: 'junit', version: '4.11'
 }

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

@@ -20,6 +20,7 @@ import ch.dissem.bitmessage.entity.payload.ObjectPayload;
 import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
 import ch.dissem.bitmessage.utils.Encode;
 
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 
@@ -27,7 +28,7 @@ import java.io.OutputStream;
  * The 'object' command sends an object that is shared throughout the network.
  */
 public class ObjectMessage implements MessagePayload {
-    private long nonce;
+    private byte[] nonce;
     private long expiresTime;
     private long objectType;
     /**
@@ -37,6 +38,7 @@ public class ObjectMessage implements MessagePayload {
     private long streamNumber;
 
     private ObjectPayload payload;
+    private byte[] payloadBytes;
 
     private ObjectMessage(Builder builder) {
         nonce = builder.nonce;
@@ -52,6 +54,14 @@ public class ObjectMessage implements MessagePayload {
         return Command.OBJECT;
     }
 
+    public byte[] getNonce() {
+        return nonce;
+    }
+
+    public long getExpiresTime() {
+        return expiresTime;
+    }
+
     public ObjectPayload getPayload() {
         return payload;
     }
@@ -63,16 +73,29 @@ public class ObjectMessage implements MessagePayload {
 
     @Override
     public void write(OutputStream stream) throws IOException {
-        Encode.int64(nonce, stream);
+        stream.write(nonce);
-        Encode.int64(expiresTime, stream);
+        stream.write(getPayloadBytes());
-        Encode.int32(objectType, stream);
+    }
-        Encode.varInt(version, stream);
+
-        Encode.varInt(streamNumber, stream);
+    public byte[] getPayloadBytes() throws IOException {
-        payload.write(stream);
+        if (payloadBytes == null) {
+            ByteArrayOutputStream stream = new ByteArrayOutputStream();
+            Encode.int64(expiresTime, stream);
+            Encode.int32(objectType, stream);
+            Encode.varInt(version, stream);
+            Encode.varInt(streamNumber, stream);
+            payload.write(stream);
+            payloadBytes = stream.toByteArray();
+        }
+        return payloadBytes;
+    }
+
+    public void setNonce(byte[] nonce) {
+        this.nonce = nonce;
     }
 
     public static final class Builder {
-        private long nonce;
+        private byte[] nonce;
         private long expiresTime;
         private long objectType;
         private long version;
@@ -82,7 +105,7 @@ public class ObjectMessage implements MessagePayload {
         public Builder() {
         }
 
-        public Builder nonce(long nonce) {
+        public Builder nonce(byte[] nonce) {
             this.nonce = nonce;
             return this;
         }

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

@@ -27,8 +27,8 @@ import java.io.OutputStream;
 public class V2Pubkey implements Pubkey {
     protected long stream;
     protected int behaviorBitfield;
-    protected byte[] publicSigningKey;
+    protected byte[] publicSigningKey; // 64 Bytes
-    protected byte[] publicEncryptionKey;
+    protected byte[] publicEncryptionKey; // 64 Bytes
 
     protected V2Pubkey() {
     }

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

@@ -63,14 +63,14 @@ public class Factory {
             case 2:
                 return new V2Pubkey.Builder()
                         .streamNumber(streamNumber)
-                        .behaviorBitfield(Decode.int64(stream))
+                        .behaviorBitfield((int) Decode.int64(stream))
                         .publicSigningKey(Decode.bytes(stream, 64))
                         .publicEncryptionKey(Decode.bytes(stream, 64))
                         .build();
             case 3:
                 V3Pubkey.Builder v3 = new V3Pubkey.Builder()
                         .streamNumber(streamNumber)
-                        .behaviorBitfield(Decode.int64(stream))
+                        .behaviorBitfield((int) Decode.int64(stream))
                         .publicSigningKey(Decode.bytes(stream, 64))
                         .publicEncryptionKey(Decode.bytes(stream, 64))
                         .nonceTrialsPerByte(Decode.varInt(stream))

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

@@ -76,7 +76,7 @@ class V3MessageFactory {
     }
 
     private ObjectMessage parseObject(InputStream stream, int length) throws IOException {
-        long nonce = Decode.int64(stream);
+        byte nonce[] = Decode.bytes(stream, 8);
         long expiresTime = Decode.int64(stream);
         long objectType = Decode.uint32(stream);
         long version = Decode.varInt(stream);

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

@@ -0,0 +1,51 @@
+/*
+ * 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;
+
+/**
+ * A helper class for working with byte arrays interpreted as unsigned big endian integers.
+ */
+public class Bytes {
+    public static void inc(byte[] nonce) {
+        for (int i = nonce.length - 1; i >= 0; i--) {
+            nonce[i]++;
+            if (nonce[i] != 0) break;
+        }
+    }
+
+    public static boolean lt(byte[] a, byte[] b) {
+        byte[] max = (a.length > b.length ? a : b);
+        byte[] min = (max == a ? b : a);
+        int diff = max.length - min.length;
+
+        for (int i = 0; i < max.length - min.length; i++) {
+            if (max[i] != 0) return a != max;
+        }
+        for (int i = diff; i < max.length; i++) {
+            if (max[i] != min[i - diff]) {
+                return lt(max[i], min[i - diff]) == (a == max);
+            }
+        }
+        return false;
+    }
+
+    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;
+    }
+}

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

@@ -16,9 +16,13 @@
 
 package ch.dissem.bitmessage.utils;
 
+import ch.dissem.bitmessage.entity.Streamable;
+
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
+import java.util.Arrays;
 
 /**
  * This class handles encoding simple types from byte stream, according to
@@ -76,4 +80,27 @@ public class Encode {
         varInt(bytes.length, stream);
         stream.write(bytes);
     }
+
+    /**
+     * Returns an array of bytes representing the given streamable object.
+     */
+    public static byte[] bytes(Streamable streamable) throws IOException {
+        ByteArrayOutputStream stream = new ByteArrayOutputStream();
+        streamable.write(stream);
+        return stream.toByteArray();
+    }
+
+    /**
+     * Returns the bytes of the given streamable object, 0-padded such that the final
+     * length is x*padding.
+     */
+    public static byte[] bytes(Streamable streamable, int padding) throws IOException {
+        ByteArrayOutputStream stream = new ByteArrayOutputStream();
+        streamable.write(stream);
+        int offset = padding - stream.size() % padding;
+        int length = stream.size() + offset;
+        byte[] result = new byte[length];
+        stream.write(result, offset, stream.size());
+        return result;
+    }
 }

domain/src/main/java/ch/dissem/bitmessage/utils/Security.java

@@ -16,37 +16,128 @@
 
 package ch.dissem.bitmessage.utils;
 
+import ch.dissem.bitmessage.entity.ObjectMessage;
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.security.GeneralSecurityException;
 import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+
+import static ch.dissem.bitmessage.utils.Bytes.inc;
 
 /**
  * Provides some methods to help with hashing and encryption.
  */
 public class Security {
-    public static byte[] sha512(byte[] data) {
+    private static final SecureRandom RANDOM = new SecureRandom();
+    private static final BigInteger TWO = BigInteger.valueOf(2);
+
+    static {
+        java.security.Security.addProvider(new BouncyCastleProvider());
+    }
+
+    public static byte[] sha512(byte[]... data) {
+        return hash("SHA-512", data);
+    }
+
+    public static byte[] doubleSha512(byte[]... data) {
+        MessageDigest mda = md("SHA-512");
+        for (byte[] d : data) {
+            mda.update(d);
+        }
+        return mda.digest(mda.digest());
+    }
+
+    public static byte[] ripemd160(byte[]... data) {
+        return hash("RIPEMD160", data);
+    }
+
+    public static byte[] sha1(byte[]... data) {
+        return hash("SHA-1", data);
+    }
+
+    public static byte[] randomBytes(int length) {
+        byte[] result = new byte[length];
+        RANDOM.nextBytes(result);
+        return result;
+    }
+
+    public static void doProofOfWork(ObjectMessage object, long nonceTrialsPerByte, long extraBytes) throws IOException {
+        // payload = embeddedTime + encodedObjectVersion + encodedStreamNumber + encrypted
+        byte[] payload = object.getPayloadBytes();
+        // payloadLength = the length of payload, in bytes, + 8 (to account for the nonce which we will append later)
+        // TTL = the number of seconds in between now and the object expiresTime.
+        //        initialHash = hash(payload)
+        byte[] initialHash = getInitialHash(object);
+
+        byte[] target = getProofOfWorkTarget(object, nonceTrialsPerByte, extraBytes);
+        // start with trialValue = 99999999999999999999
+        byte[] trialValue;
+        // also start with nonce = 0 where nonce is 8 bytes in length and can be hashed as if it is a string.
+        byte[] nonce = new byte[8];
+        MessageDigest mda = md("SHA-512");
+        do {
+            inc(nonce);
+            mda.update(nonce);
+            mda.update(initialHash);
+            trialValue = bytes(mda.digest(mda.digest()), 8);
+        } while (Bytes.lt(target, trialValue));
+        object.setNonce(nonce);
+    }
+
+    /**
+     * @param object
+     * @param nonceTrialsPerByte
+     * @param extraBytes
+     * @throws IOException if proof of work doesn't check out
+     */
+    public static void checkProofOfWork(ObjectMessage object, long nonceTrialsPerByte, long extraBytes) throws IOException {
+        // nonce = the first 8 bytes of payload
+        byte[] nonce = object.getNonce();
+        byte[] initialHash = getInitialHash(object);
+        // resultHash = hash(hash( nonce || initialHash ))
+        byte[] resultHash = Security.doubleSha512(nonce, initialHash);
+        // POWValue = the first eight bytes of resultHash converted to an integer
+        byte[] powValue = bytes(resultHash, 8);
+
+        if (Bytes.lt(getProofOfWorkTarget(object, nonceTrialsPerByte, extraBytes), powValue)) {
+            throw new IOException("Insufficient proof of work");
+        }
+    }
+
+    private static byte[] getInitialHash(ObjectMessage object) throws IOException {
+        return Security.sha512(object.getPayloadBytes());
+    }
+
+    private static byte[] getProofOfWorkTarget(ObjectMessage object, long nonceTrialsPerByte, long extraBytes) throws IOException {
+        BigInteger TTL = BigInteger.valueOf(object.getExpiresTime() - (System.currentTimeMillis() / 1000));
+        BigInteger numerator = TWO.pow(64);
+        BigInteger powLength = BigInteger.valueOf(object.getPayloadBytes().length + extraBytes);
+        BigInteger denominator = BigInteger.valueOf(nonceTrialsPerByte).multiply(powLength.add(powLength.multiply(TTL).divide(BigInteger.valueOf(2).pow(16))));
+        return numerator.divide(denominator).toByteArray();
+    }
+
+    private static byte[] hash(String algorithm, byte[]... data) {
+        MessageDigest mda = md(algorithm);
+        for (byte[] d : data) {
+            mda.update(d);
+        }
+        return mda.digest();
+    }
+
+    private static MessageDigest md(String algorithm) {
         try {
-            MessageDigest mda = MessageDigest.getInstance("SHA-512");
+            return MessageDigest.getInstance(algorithm, "BC");
-            return mda.digest(data);
+        } catch (GeneralSecurityException e) {
-        } catch (NoSuchAlgorithmException e) {
             throw new RuntimeException(e);
         }
     }
 
-    public static byte[] doubleSha512(byte[] data) {
+    private static byte[] bytes(byte[] data, int count) {
-        try {
+        byte[] result = new byte[count];
-            MessageDigest mda = MessageDigest.getInstance("SHA-512");
+        System.arraycopy(data, 0, result, 0, count);
-            return mda.digest(mda.digest(data));
+        return result;
-        } catch (NoSuchAlgorithmException e) {
-            throw new RuntimeException(e);
-        }
-    }
-
-    public static byte[] ripemd160(byte[] data) {
-        try {
-            MessageDigest mda = MessageDigest.getInstance("RIPEMD-160");
-            return mda.digest(data);
-        } catch (NoSuchAlgorithmException e) {
-            throw new RuntimeException(e);
-        }
     }
 }

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

@@ -0,0 +1,53 @@
+/*
+ * 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 org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.math.BigInteger;
+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 {
+    @Test
+    public void testIncrement() throws IOException {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Encode.int16(256, out);
+
+        byte[] bytes = {0, -1};
+        Bytes.inc(bytes);
+        assertArrayEquals(out.toByteArray(), bytes);
+    }
+
+    @Test
+    public void testLowerThan() {
+        Random rnd = new Random();
+        for (int i = 0; i < 1000; i++) {
+            BigInteger a = BigInteger.valueOf(rnd.nextLong()).pow((rnd.nextInt(5) + 1)).abs();
+            BigInteger b = BigInteger.valueOf(rnd.nextLong()).pow((rnd.nextInt(5) + 1)).abs();
+            System.out.println("a = " + a.toString(16) + "\tb = " + b.toString(16));
+            assertEquals(a.compareTo(b) == -1, Bytes.lt(a.toByteArray(), b.toByteArray()));
+        }
+    }
+}

domain/src/test/java/ch/dissem/bitmessage/utils/SecurityTest.java

@@ -0,0 +1,90 @@
+/*
+ * 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.entity.ObjectMessage;
+import ch.dissem.bitmessage.entity.payload.GenericPayload;
+import org.junit.Test;
+
+import javax.xml.bind.DatatypeConverter;
+import java.io.IOException;
+import java.util.Calendar;
+import java.util.GregorianCalendar;
+
+import static org.junit.Assert.assertArrayEquals;
+
+/**
+ * Created by chris on 10.04.15.
+ */
+public class SecurityTest {
+    public static final byte[] TEST_VALUE = "teststring".getBytes();
+    public static final byte[] TEST_SHA1 = DatatypeConverter.parseHexBinary(""
+            + "b8473b86d4c2072ca9b08bd28e373e8253e865c4");
+    public static final byte[] TEST_SHA512 = DatatypeConverter.parseHexBinary(""
+            + "6253b39071e5df8b5098f59202d414c37a17d6a38a875ef5f8c7d89b0212b028"
+            + "692d3d2090ce03ae1de66c862fa8a561e57ed9eb7935ce627344f742c0931d72");
+    public static final byte[] TEST_RIPEMD160 = DatatypeConverter.parseHexBinary(""
+            + "cd566972b5e50104011a92b59fa8e0b1234851ae");
+
+    @Test
+    public void testRipemd160() {
+        assertArrayEquals(TEST_RIPEMD160, Security.ripemd160(TEST_VALUE));
+    }
+
+    @Test
+    public void testSha1() {
+        assertArrayEquals(TEST_SHA1, Security.sha1(TEST_VALUE));
+    }
+
+    @Test
+    public void testSha512() {
+        assertArrayEquals(TEST_SHA512, Security.sha512(TEST_VALUE));
+    }
+
+    @Test
+    public void testChaining() {
+        assertArrayEquals(TEST_SHA512, Security.sha512("test".getBytes(), "string".getBytes()));
+    }
+
+    @Test
+    public void testDoubleHash() {
+        assertArrayEquals(Security.sha512(TEST_SHA512), Security.doubleSha512(TEST_VALUE));
+    }
+
+    @Test(expected = IOException.class)
+    public void testProofOfWorkFails() throws IOException {
+        ObjectMessage objectMessage = new ObjectMessage.Builder()
+                .nonce(new byte[8])
+                .expiresTime(300 + (System.currentTimeMillis() / 1000)) // 5 minutes
+                .payload(new GenericPayload(1, new byte[0]))
+                .build();
+        Security.checkProofOfWork(objectMessage, 1000, 1000);
+    }
+
+    @Test
+    public void testDoProofOfWork() throws IOException {
+        Calendar expires = new GregorianCalendar();
+        expires.add(1, Calendar.HOUR);
+        ObjectMessage objectMessage = new ObjectMessage.Builder()
+                .nonce(new byte[8])
+                .expiresTime(expires.getTimeInMillis() / 1000)
+                .payload(new GenericPayload(1, new byte[0]))
+                .build();
+        Security.doProofOfWork(objectMessage, 1000, 1000);
+        Security.checkProofOfWork(objectMessage, 1000, 1000);
+    }
+}