diff --git a/app/build.gradle b/app/build.gradle
index 41b9321..330ee5d 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -14,8 +14,11 @@ if (project.hasProperty("project.configs")
 //noinspection GroovyMissingReturnStatement
 android {
     compileSdkVersion 27
-    buildToolsVersion "26.0.2"
+    buildToolsVersion "27.0.3"
 
+    signingConfigs {
+        release
+    }
     defaultConfig {
         applicationId "ch.dissem.apps.${appName.toLowerCase()}"
         minSdkVersion 19
@@ -69,10 +72,11 @@ dependencies {
 
     implementation "ch.dissem.jabit:jabit-core:$jabitVersion"
     implementation "ch.dissem.jabit:jabit-networking:$jabitVersion"
-    implementation "ch.dissem.jabit:jabit-cryptography-spongy:$jabitVersion"
     implementation "ch.dissem.jabit:jabit-extensions:$jabitVersion"
     implementation "ch.dissem.jabit:jabit-wif:$jabitVersion"
     implementation "ch.dissem.jabit:jabit-exports:$jabitVersion"
+    implementation "ch.dissem.jabit:jabit-cryptography-spongy:$jabitVersion"
+    testImplementation "ch.dissem.jabit:jabit-cryptography-bouncy:$jabitVersion"
 
     implementation 'org.slf4j:slf4j-android:1.7.25'
 
diff --git a/app/src/test/java/ch/dissem/bitmessage/repository/AndroidMessageRepositoryTest.kt b/app/src/test/java/ch/dissem/bitmessage/repository/AndroidMessageRepositoryTest.kt
index ead5c9d..de5acd2 100644
--- a/app/src/test/java/ch/dissem/bitmessage/repository/AndroidMessageRepositoryTest.kt
+++ b/app/src/test/java/ch/dissem/bitmessage/repository/AndroidMessageRepositoryTest.kt
@@ -21,7 +21,7 @@ import ch.dissem.apps.abit.repository.AndroidAddressRepository
 import ch.dissem.apps.abit.repository.AndroidLabelRepository
 import ch.dissem.apps.abit.repository.AndroidMessageRepository
 import ch.dissem.apps.abit.repository.SqlHelper
-import ch.dissem.bitmessage.cryptography.sc.SpongyCryptography
+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
@@ -69,7 +69,7 @@ class AndroidMessageRepositoryTest : TestBase() {
         val labelRepo = AndroidLabelRepository(sqlHelper, RuntimeEnvironment.application)
         repo = AndroidMessageRepository(sqlHelper)
         mockedInternalContext(
-            cryptography = SpongyCryptography(),
+            cryptography = BouncyCryptography(),
             addressRepository = addressRepo,
             labelRepository = labelRepo,
             messageRepository = repo,
diff --git a/app/src/test/java/ch/dissem/bitmessage/repository/AndroidProofOfWorkRepositoryTest.kt b/app/src/test/java/ch/dissem/bitmessage/repository/AndroidProofOfWorkRepositoryTest.kt
index 5c06974..a86baa7 100644
--- a/app/src/test/java/ch/dissem/bitmessage/repository/AndroidProofOfWorkRepositoryTest.kt
+++ b/app/src/test/java/ch/dissem/bitmessage/repository/AndroidProofOfWorkRepositoryTest.kt
@@ -59,7 +59,6 @@ class AndroidProofOfWorkRepositoryTest : TestBase() {
     fun setUp() {
         RuntimeEnvironment.application.deleteDatabase(SqlHelper.DATABASE_NAME)
         val sqlHelper = SqlHelper(RuntimeEnvironment.application)
-
         addressRepo = AndroidAddressRepository(sqlHelper)
         messageRepo = AndroidMessageRepository(sqlHelper)
         repo = AndroidProofOfWorkRepository(sqlHelper)
@@ -94,12 +93,14 @@ class AndroidProofOfWorkRepositoryTest : TestBase() {
         messageRepo.save(plaintext)
         plaintext.ackMessage!!.let { ackMessage ->
             initialHash2 = cryptography().getInitialHash(ackMessage)
-            repo.putObject(ProofOfWorkRepository.Item(
-                objectMessage = ackMessage,
-                nonceTrialsPerByte = 1000, extraBytes = 1000,
-                expirationTime = UnixTime.now + 10 * UnixTime.MINUTE,
-                message = plaintext
-            ))
+            repo.putObject(
+                ProofOfWorkRepository.Item(
+                    objectMessage = ackMessage,
+                    nonceTrialsPerByte = 1000, extraBytes = 1000,
+                    expirationTime = UnixTime.now + 10 * UnixTime.MINUTE,
+                    message = plaintext
+                )
+            )
         }
     }
 
@@ -132,13 +133,15 @@ class AndroidProofOfWorkRepositoryTest : TestBase() {
             .build()
         messageRepo.save(plaintext)
         plaintext.ackMessage!!.let { ackMessage ->
-            repo.putObject(ProofOfWorkRepository.Item(
-                objectMessage = ackMessage,
-                nonceTrialsPerByte = 1000,
-                extraBytes = 1000,
-                expirationTime = UnixTime.now + 10 * UnixTime.MINUTE,
-                message = plaintext
-            ))
+            repo.putObject(
+                ProofOfWorkRepository.Item(
+                    objectMessage = ackMessage,
+                    nonceTrialsPerByte = 1000,
+                    extraBytes = 1000,
+                    expirationTime = UnixTime.now + 10 * UnixTime.MINUTE,
+                    message = plaintext
+                )
+            )
         }
         assertThat(repo.getItems().size, `is`(sizeBefore + 1))
     }
@@ -147,7 +150,10 @@ class AndroidProofOfWorkRepositoryTest : TestBase() {
     fun `ensure item can be retrieved`() {
         val item = repo.getItem(initialHash1)
         assertThat(item, notNullValue())
-        assertThat<ObjectPayload>(item.objectMessage.payload, instanceOf<ObjectPayload>(GetPubkey::class.java))
+        assertThat<ObjectPayload>(
+            item.objectMessage.payload,
+            instanceOf<ObjectPayload>(GetPubkey::class.java)
+        )
         assertThat(item.nonceTrialsPerByte, `is`(1000L))
         assertThat(item.extraBytes, `is`(1000L))
     }
@@ -156,7 +162,10 @@ class AndroidProofOfWorkRepositoryTest : TestBase() {
     fun `ensure ack item can be retrieved`() {
         val item = repo.getItem(initialHash2)
         assertThat(item, notNullValue())
-        assertThat<ObjectPayload>(item.objectMessage.payload, instanceOf<ObjectPayload>(GenericPayload::class.java))
+        assertThat<ObjectPayload>(
+            item.objectMessage.payload,
+            instanceOf<ObjectPayload>(GenericPayload::class.java)
+        )
         assertThat(item.nonceTrialsPerByte, `is`(1000L))
         assertThat(item.extraBytes, `is`(1000L))
         assertThat(item.expirationTime, not<Number>(0))
diff --git a/build.gradle b/build.gradle
index bcaecb5..ed23df1 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,12 +1,12 @@
 buildscript {
-    ext.kotlin_version = '1.2.30'
+    ext.kotlin_version = '1.2.31'
     ext.anko_version = '0.10.4'
     repositories {
         jcenter()
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.1'
+        classpath 'com.android.tools.build:gradle:3.1.0'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath 'com.github.ben-manes:gradle-versions-plugin:0.17.0'