The olm objects are serialized as byte[] instead of strings.

12 files changed, 81 insertions, 84 deletions

diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/CommonSerializeUtils.java b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/CommonSerializeUtils.java
index 72437e4..b8c7215 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/CommonSerializeUtils.java
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/CommonSerializeUtils.java
@@ -39,11 +39,11 @@ abstract class CommonSerializeUtils {
         aOutStream.defaultWriteObject();
 
         // generate serialization key
-        String key = OlmUtility.getRandomKey();
+        byte[] key = OlmUtility.getRandomKey();
 
         // compute pickle string
         StringBuffer errorMsg = new StringBuffer();
-        String pickledData = serialize(key, errorMsg);
+        byte[] pickledData = serialize(key, errorMsg);
 
         if(null == pickledData) {
             throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_SERIALIZATION, String.valueOf(errorMsg));
@@ -62,12 +62,12 @@ abstract class CommonSerializeUtils {
     protected void deserialize(ObjectInputStream aInStream) throws IOException, ClassNotFoundException {
         aInStream.defaultReadObject();
 
-        String key = (String) aInStream.readObject();
-        String pickledData = (String) aInStream.readObject();
+        byte[] key = (byte[]) aInStream.readObject();
+        byte[] pickledData = (byte[]) aInStream.readObject();
 
-        if (TextUtils.isEmpty(key)) {
+        if (null == key) {
             throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_DESERIALIZATION, OlmException.EXCEPTION_MSG_INVALID_PARAMS_DESERIALIZATION+" key");
-        } else if (TextUtils.isEmpty(pickledData)) {
+        } else if (null == pickledData) {
             throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_DESERIALIZATION, OlmException.EXCEPTION_MSG_INVALID_PARAMS_DESERIALIZATION+" pickle");
         }
 
@@ -75,6 +75,6 @@ abstract class CommonSerializeUtils {
         Log.d(LOG_TAG,"## deserializeObject(): success");
     }
 
-    protected abstract String serialize(String aKey, StringBuffer aErrorMsg);
-    protected abstract void deserialize(String aSerializedData, String aKey) throws IOException;
+    protected abstract byte[] serialize(byte[] aKey, StringBuffer aErrorMsg);
+    protected abstract void deserialize(byte[] aSerializedData, byte[] aKey) throws IOException;
 }
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java
index 9d8e6d6..3a78365 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java
@@ -418,27 +418,27 @@ public class OlmAccount extends CommonSerializeUtils implements Serializable {
     }
 
     /**
-     * Return an account as a base64 string.<br>
+     * Return an account as a bytes buffer.<br>
      * The account is serialized and encrypted with aKey.
      * In case of failure, an error human readable
      * description is provide in aErrorMsg.
      * @param aKey encryption key
      * @param aErrorMsg error message description
-     * @return pickled base64 string if operation succeed, null otherwise
+     * @return the account as bytes buffer
      */
     @Override
-    protected String serialize(String aKey, StringBuffer aErrorMsg) {
-        String pickleRetValue = null;
+    protected byte[] serialize(byte[] aKey, StringBuffer aErrorMsg) {
+        byte[] pickleRetValue = null;
 
         // sanity check
         if(null == aErrorMsg) {
             Log.e(LOG_TAG,"## serialize(): invalid parameter - aErrorMsg=null");
-        } else if(TextUtils.isEmpty(aKey)) {
+        } else if (null ==  aKey) {
             aErrorMsg.append("Invalid input parameters in serializeDataWithKey()");
         } else {
             aErrorMsg.setLength(0);
             try {
-                pickleRetValue = new String(serializeJni(aKey.getBytes("UTF-8")), "UTF-8");
+                pickleRetValue = serializeJni(aKey);
             } catch (Exception e) {
                 Log.e(LOG_TAG, "## serialize() failed " + e.getMessage());
                 aErrorMsg.append(e.getMessage());
@@ -451,13 +451,13 @@ public class OlmAccount extends CommonSerializeUtils implements Serializable {
     private native byte[] serializeJni(byte[] aKey);
 
     /**
-     * Loads an account from a pickled base64 string.<br>
-     * See {@link #serialize(String, StringBuffer)}
-     * @param aSerializedData pickled account in a base64 string format
+     * Loads an account from a pickled bytes buffer.<br>
+     * See {@link #serialize(byte[], StringBuffer)}
+     * @param aSerializedData bytes buffer
      * @param aKey key used to encrypted
      */
     @Override
-    protected void deserialize(String aSerializedData, String aKey) throws IOException {
+    protected void deserialize(byte[] aSerializedData, byte[] aKey) throws IOException {
         if (!createNewAccount()) {
             throw new OlmException(OlmException.EXCEPTION_CODE_INIT_ACCOUNT_CREATION,OlmException.EXCEPTION_MSG_INIT_ACCOUNT_CREATION);
         }
@@ -466,10 +466,10 @@ public class OlmAccount extends CommonSerializeUtils implements Serializable {
 
         try {
             String jniError;
-            if (TextUtils.isEmpty(aSerializedData) || TextUtils.isEmpty(aKey)) {
+            if ((null == aSerializedData) || (null == aKey)) {
                 Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
                 errorMsg.append("invalid input parameters");
-            } else if (null != (jniError = deserializeJni(aSerializedData.getBytes("UTF-8"), aKey.getBytes("UTF-8")))) {
+            } else if (null != (jniError = deserializeJni(aSerializedData, aKey))) {
                 errorMsg.append(jniError);
             }
         } catch (Exception e) {
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
index 41eeba1..dc1b80d 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
@@ -44,7 +44,7 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
     /**
      * Result in {@link #decryptMessage(String)}
      */
-    static class DecryptMessageResult {
+    public static class DecryptMessageResult {
         /** decrypt message **/
         public String mDecryptedMessage;
 
@@ -135,6 +135,7 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
     /**
      * Retrieve the base64-encoded identifier for this inbound group session.
      * @return the session ID
+     * @throws OlmException the failure reason
      */
     public String sessionIdentifier() throws OlmException {
         try {
@@ -197,28 +198,28 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
     }
 
     /**
-     * Return the current inbound group session as a base64 serialized string.<br>
+     * Return the current inbound group session as a bytes buffer.<br>
      * The session is serialized and encrypted with aKey.
      * In case of failure, an error human readable
      * description is provide in aErrorMsg.
      * @param aKey encryption key
      * @param aErrorMsg error message description
-     * @return pickled base64 string if operation succeed, null otherwise
+     * @return pickled bytes buffer if operation succeed, null otherwise
      */
     @Override
-    protected String serialize(String aKey, StringBuffer aErrorMsg) {
-        String pickleRetValue = null;
+    protected byte[] serialize(byte[] aKey, StringBuffer aErrorMsg) {
+        byte[] pickleRetValue = null;
 
         // sanity check
         if(null == aErrorMsg) {
             Log.e(LOG_TAG,"## serialize(): invalid parameter - aErrorMsg=null");
             aErrorMsg.append("aErrorMsg=null");
-        } else if(TextUtils.isEmpty(aKey)) {
+        } else if (null == aKey) {
             aErrorMsg.append("Invalid input parameters in serialize()");
         } else {
             aErrorMsg.setLength(0);
             try {
-                pickleRetValue = new String(serializeJni(aKey.getBytes("UTF-8")), "UTF-8");
+                pickleRetValue = serializeJni(aKey);
             } catch (Exception e) {
                 Log.e(LOG_TAG, "## serialize() failed " + e.getMessage());
                 aErrorMsg.append(e.getMessage());
@@ -228,7 +229,7 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
         return pickleRetValue;
     }
     /**
-     * JNI counter part of {@link #serialize(String, StringBuffer)}.
+     * JNI counter part of {@link #serialize(byte[], StringBuffer)}.
      * @param aKey encryption key
      * @return pickled base64 string if operation succeed, null otherwise
      */
@@ -236,12 +237,12 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
 
     /**
      * Loads an account from a pickled base64 string.<br>
-     * See {@link #serialize(String, StringBuffer)}
-     * @param aSerializedData pickled account in a base64 string format
+     * See {@link #serialize(byte[], StringBuffer)}
+     * @param aSerializedData pickled account in a bytes buffer
      * @param aKey key used to encrypted
      */
     @Override
-    protected void deserialize(String aSerializedData, String aKey) throws IOException {
+    protected void deserialize(byte[] aSerializedData, byte[] aKey) throws IOException {
         if (!createNewSession()) {
             throw new OlmException(OlmException.EXCEPTION_CODE_INIT_ACCOUNT_CREATION,OlmException.EXCEPTION_MSG_INIT_ACCOUNT_CREATION);
         }
@@ -250,10 +251,10 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
 
         try {
             String jniError;
-            if (TextUtils.isEmpty(aSerializedData) || TextUtils.isEmpty(aKey)) {
+            if ((null == aSerializedData) || (null == aKey)) {
                 Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
                 errorMsg.append("invalid input parameters");
-            } else if (null != (jniError = deserializeJni(aSerializedData.getBytes("UTF-8"), aKey.getBytes("UTF-8")))) {
+            } else if (null != (jniError = deserializeJni(aSerializedData, aKey))) {
                 errorMsg.append(jniError);
             }
         } catch (Exception e) {
@@ -268,9 +269,9 @@ public class OlmInboundGroupSession extends CommonSerializeUtils implements Seri
     }
 
     /**
-     * JNI counter part of {@link #deserialize(String, String)}.
-     * @param aSerializedData pickled session in a base64 string format
-     * @param aKey key used to encrypted in {@link #serialize(String, StringBuffer)}
+     * JNI counter part of {@link #deserialize(byte[], byte[])}.
+     * @param aSerializedData pickled session in a base64 sbytes buffer
+     * @param aKey key used to encrypted in {@link #serialize(byte[], StringBuffer)}
      * @return null if operation succeed, an error message if operation failed
      */
     private native String deserializeJni(byte[] aSerializedData, byte[] aKey);
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java
index c27addb..534636c 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java
@@ -117,6 +117,7 @@ public class OlmOutboundGroupSession extends CommonSerializeUtils implements Ser
     /**
      * Get a base64-encoded identifier for this session.
      * @return session identifier
+     * @throws OlmException the failure reason
      */
     public String sessionIdentifier() throws OlmException {
         try {
@@ -210,26 +211,26 @@ public class OlmOutboundGroupSession extends CommonSerializeUtils implements Ser
     }
 
     /**
-     * Return the current outbound group session as a base64 serialized string.<br>
+     * Return the current outbound group session as a base64 byte buffers.<br>
      * The session is serialized and encrypted with aKey.
      * In case of failure, an error human readable
      * description is provide in aErrorMsg.
      * @param aKey encryption key
      * @param aErrorMsg error message description
-     * @return pickled base64 string if operation succeed, null otherwise
+     * @return pickled base64 bytes buffer if operation succeed, null otherwise
      */
     @Override
-    protected String serialize(String aKey, StringBuffer aErrorMsg) {
-        String pickleRetValue = null;
+    protected byte[] serialize(byte[] aKey, StringBuffer aErrorMsg) {
+        byte[] pickleRetValue = null;
 
         // sanity check
         if(null == aErrorMsg) {
             Log.e(LOG_TAG,"## serialize(): invalid parameter - aErrorMsg=null");
-        } else if(TextUtils.isEmpty(aKey)) {
+        } else if (null == aKey) {
             aErrorMsg.append("Invalid input parameters in serialize()");
         } else {
             try {
-                pickleRetValue = serializeJni(aKey.getBytes("UTF-8"));
+                pickleRetValue = serializeJni(aKey);
             } catch (Exception e) {
                 Log.e(LOG_TAG,"## serialize(): failed " + e.getMessage());
                 aErrorMsg.append(e.getMessage());
@@ -238,17 +239,17 @@ public class OlmOutboundGroupSession extends CommonSerializeUtils implements Ser
 
         return pickleRetValue;
     }
-    private native String serializeJni(byte[] aKey);
+    private native byte[] serializeJni(byte[] aKey);
 
 
     /**
      * Loads an account from a pickled base64 string.<br>
-     * See {@link #serialize(String, StringBuffer)}
-     * @param aSerializedData pickled account in a base64 string format
+     * See {@link #serialize(byte[], StringBuffer)}
+     * @param aSerializedData pickled account in a base64 bytes buffer
      * @param aKey key used to encrypted
      */
     @Override
-    protected void deserialize(String aSerializedData, String aKey) throws IOException {
+    protected void deserialize(byte[] aSerializedData, byte[] aKey) throws IOException {
         if (!createNewSession()) {
             throw new OlmException(OlmException.EXCEPTION_CODE_INIT_ACCOUNT_CREATION,OlmException.EXCEPTION_MSG_INIT_ACCOUNT_CREATION);
         }
@@ -257,10 +258,10 @@ public class OlmOutboundGroupSession extends CommonSerializeUtils implements Ser
 
         try {
             String jniError;
-            if (TextUtils.isEmpty(aSerializedData) || TextUtils.isEmpty(aKey)) {
+            if ((null == aSerializedData) || (null == aKey)) {
                 Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
                 errorMsg.append("invalid input parameters");
-            } else if (null != (jniError = deserializeJni(aSerializedData.getBytes("UTF-8"), aKey.getBytes("UTF-8")))) {
+            } else if (null != (jniError = deserializeJni(aSerializedData, aKey))) {
                 errorMsg.append(jniError);
             }
         } catch (Exception e) {
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
index 9138309..bc190ed 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
@@ -336,27 +336,27 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
     }
 
     /**
-     * Return a session as a base64 string.<br>
+     * Return a session as a bytes buffer.<br>
      * The account is serialized and encrypted with aKey.
      * In case of failure, an error human readable
      * description is provide in aErrorMsg.
      * @param aKey encryption key
      * @param aErrorMsg error message description
-     * @return pickled base64 string if operation succeed, null otherwise
+     * @return session as a bytes buffer
      */
     @Override
-    protected String serialize(String aKey, StringBuffer aErrorMsg) {
-        String pickleRetValue = null;
+    protected byte[] serialize(byte[] aKey, StringBuffer aErrorMsg) {
+        byte[] pickleRetValue = null;
 
         // sanity check
         if(null == aErrorMsg) {
             Log.e(LOG_TAG,"## serializeDataWithKey(): invalid parameter - aErrorMsg=null");
-        } else if(TextUtils.isEmpty(aKey)) {
+        } else if (null == aKey) {
             aErrorMsg.append("Invalid input parameters in serializeDataWithKey()");
         } else {
             aErrorMsg.setLength(0);
             try {
-                pickleRetValue = serializeJni(aKey.getBytes("UTF-8"));
+                pickleRetValue = serializeJni(aKey);
             } catch (Exception e) {
                 Log.e(LOG_TAG,"## serializeDataWithKey(): failed " + e.getMessage());
                 aErrorMsg.append(e.getMessage());
@@ -365,16 +365,16 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
 
         return pickleRetValue;
     }
-    private native String serializeJni(byte[] aKey);
+    private native byte[] serializeJni(byte[] aKey);
 
     /**
      * Loads an account from a pickled base64 string.<br>
-     * See {@link #serialize(String, StringBuffer)}
+     * See {@link #serialize(byte[], StringBuffer)}
      * @param aSerializedData pickled account in a base64 string format
      * @param aKey key used to encrypted
      */
     @Override
-    protected void deserialize(String aSerializedData, String aKey) throws IOException {
+    protected void deserialize(byte[] aSerializedData, byte[] aKey) throws IOException {
         if (!createNewSession()) {
             throw new OlmException(OlmException.EXCEPTION_CODE_INIT_ACCOUNT_CREATION,OlmException.EXCEPTION_MSG_INIT_ACCOUNT_CREATION);
         }
@@ -383,10 +383,10 @@ public class OlmSession extends CommonSerializeUtils implements Serializable {
 
         try {
             String jniError;
-            if (TextUtils.isEmpty(aSerializedData) || TextUtils.isEmpty(aKey)) {
+            if ((null == aSerializedData) || (null == aKey)) {
                 Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
                 errorMsg.append("invalid input parameters");
-            } else if (null != (jniError = deserializeJni(aSerializedData.getBytes("UTF-8"), aKey.getBytes("UTF-8")))) {
+            } else if (null != (jniError = deserializeJni(aSerializedData, aKey))) {
                 errorMsg.append(jniError);
             }
         } catch (Exception e) {
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmUtility.java b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmUtility.java
index d3c185f..28d8b58 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmUtility.java
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/java/org/matrix/olm/OlmUtility.java
@@ -135,13 +135,13 @@ public class OlmUtility {
 
     /**
      * Helper method to compute a string based on random integers.
-     * @return string containing randoms integer values
+     * @return bytes buffer containing randoms integer values
      */
-    public static String getRandomKey() {
+    public static byte[] getRandomKey() {
         SecureRandom secureRandom = new SecureRandom();
         byte[] buffer = new byte[RANDOM_KEY_SIZE];
         secureRandom.nextBytes(buffer);
-        return new String(buffer);
+        return buffer;
     }
 
     /**
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_account.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_account.cpp
index bac8b34..53eace7 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_account.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_account.cpp
@@ -558,7 +558,6 @@ JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thi
         size_t pickledLength = olm_pickle_account_length(accountPtr);
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## serializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
-        LOGD(" ## serializeJni(): key=%s",(char const *)keyPtr);
 
         void *pickledPtr = malloc((pickledLength+1)*sizeof(uint8_t));
 
@@ -586,8 +585,8 @@ JNIEXPORT jbyteArray OLM_ACCOUNT_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thi
 
                 LOGD(" ## serializeJni(): success - result=%lu pickled=%s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
 
-                pickledDataRetValue = env->NewByteArray(pickledLength+1);
-                env->SetByteArrayRegion(pickledDataRetValue, 0 , pickledLength+1, (jbyte*)pickledPtr);
+                pickledDataRetValue = env->NewByteArray(pickledLength);
+                env->SetByteArrayRegion(pickledDataRetValue, 0 , pickledLength, (jbyte*)pickledPtr);
             }
 
             free(pickledPtr);
@@ -643,7 +642,6 @@ JNIEXPORT jstring OLM_ACCOUNT_FUNC_DEF(deserializeJni)(JNIEnv *env, jobject thiz
         size_t pickledLength = (size_t)env->GetArrayLength(aSerializedDataBuffer);
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## deserializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
-        LOGD(" ## deserializeJni(): key=%s",(char const *)keyPtr);
         LOGD(" ## deserializeJni(): pickled=%s",(char const *)pickledPtr);
 
         size_t result = olm_unpickle_account(accountPtr,
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
index 223b3d8..315f607 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp
@@ -361,7 +361,6 @@ JNIEXPORT jbyteArray OLM_INBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *en
         size_t pickledLength = olm_pickle_inbound_group_session_length(sessionPtr);
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## serializeJni(): pickledLength=%lu keyLength=%lu", static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
-        LOGD(" ## serializeJni(): key=%s",(char const *)keyPtr);
 
         void *pickledPtr = malloc((pickledLength+1)*sizeof(uint8_t));
 
@@ -444,7 +443,6 @@ JNIEXPORT jstring OLM_INBOUND_GROUP_SESSION_FUNC_DEF(deserializeJni)(JNIEnv *env
         size_t pickledLength = (size_t)env->GetArrayLength(aSerializedDataBuffer);
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## deserializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
-        LOGD(" ## deserializeJni(): key=%s",(char const *)keyPtr);
         LOGD(" ## deserializeJni(): pickled=%s",(char const *)pickledPtr);
 
         size_t result = olm_unpickle_inbound_group_session(sessionPtr,
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
index 982840c..e8fd38b 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp
@@ -381,11 +381,11 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIE
 * @param aKey key used to encrypt the serialized session data
 * @return a base64 string if operation succeed, null otherwise
 **/
-JNIEXPORT jstring OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKeyBuffer)
+JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKeyBuffer)
 {
     const char* errorMessage = NULL;
+    jbyteArray returnValue = 0;
 
-    jstring pickledDataRetValue = 0;
     jbyte* keyPtr = NULL;
     OlmOutboundGroupSession* sessionPtr = NULL;
 
@@ -411,7 +411,6 @@ JNIEXPORT jstring OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env,
         size_t pickledLength = olm_pickle_outbound_group_session_length(sessionPtr);
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## serializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
-        LOGD(" ## serializeJni(): key=%s",(char const *)keyPtr);
 
         void *pickledPtr = malloc((pickledLength+1)*sizeof(uint8_t));
 
@@ -436,8 +435,10 @@ JNIEXPORT jstring OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env,
             {
                 // build success output
                 (static_cast<char*>(pickledPtr))[pickledLength] = static_cast<char>('\0');
-                pickledDataRetValue = env->NewStringUTF((const char*)pickledPtr);
                 LOGD(" ## serializeJni(): success - result=%lu pickled=%s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
+
+                returnValue = env->NewByteArray(pickledLength);
+                env->SetByteArrayRegion(returnValue, 0 , pickledLength, (jbyte*)pickledPtr);
             }
         }
 
@@ -455,7 +456,7 @@ JNIEXPORT jstring OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env,
         env->ThrowNew(env->FindClass("java/lang/Exception"), errorMessage);
     }
 
-    return pickledDataRetValue;
+    return returnValue;
 }
 
 
@@ -493,7 +494,6 @@ JNIEXPORT jstring OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(deserializeJni)(JNIEnv *en
         size_t pickledLength = (size_t)env->GetArrayLength(aSerializedDataBuffer);
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## deserializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
-        LOGD(" ## deserializeJni(): key=%s",(char const *)keyPtr);
         LOGD(" ## deserializeJni(): pickled=%s",(char const *)pickledPtr);
 
         size_t result = olm_unpickle_outbound_group_session(sessionPtr,
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.h b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.h
index 1156b77..fb3bf87 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.h
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.h
@@ -40,7 +40,7 @@ JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(sessionKeyJni)(JNIEnv *
 JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(encryptMessageJni)(JNIEnv *env, jobject thiz, jbyteArray aClearMsgBuffer);
 
 // serialization
-JNIEXPORT jstring OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKey);
+JNIEXPORT jbyteArray OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKey);
 JNIEXPORT jstring OLM_OUTBOUND_GROUP_SESSION_FUNC_DEF(deserializeJni)(JNIEnv *env, jobject thiz, jbyteArray aSerializedData, jbyteArray aKey);
 
 #ifdef __cplusplus
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp
index f09ace6..7cde2cd 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp
@@ -754,7 +754,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobjec
 */
 JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(getSessionIdentifierJni)(JNIEnv *env, jobject thiz)
 {
-    const char* errorMessage = NULL;
+     const char* errorMessage = NULL;
      jbyteArray returnValue = 0;
 
      LOGD("## getSessionIdentifierJni(): IN ");
@@ -817,11 +817,11 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(getSessionIdentifierJni)(JNIEnv *env,
 * @param aKey key used to encrypt the serialized session data
 * @return a base64 string if operation succeed, null otherwise
 **/
-JNIEXPORT jstring OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKeyBuffer)
+JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKeyBuffer)
 {
     const char* errorMessage = NULL;
+    jbyteArray returnValue = 0;
 
-    jstring pickledDataRetValue = 0;
     jbyte* keyPtr = NULL;
     OlmSession* sessionPtr = NULL;
 
@@ -847,7 +847,6 @@ JNIEXPORT jstring OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz,
         size_t pickledLength = olm_pickle_session_length(sessionPtr);
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## serializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
-        LOGD(" ## serializeJni(): key=%s",(char const *)keyPtr);
 
         void *pickledPtr = malloc((pickledLength+1)*sizeof(uint8_t));
 
@@ -872,8 +871,10 @@ JNIEXPORT jstring OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz,
             {
                 // build success output
                 (static_cast<char*>(pickledPtr))[pickledLength] = static_cast<char>('\0');
-                pickledDataRetValue = env->NewStringUTF((const char*)pickledPtr);
                 LOGD(" ## serializeJni(): success - result=%lu pickled=%s", static_cast<long unsigned int>(result), static_cast<char*>(pickledPtr));
+
+                returnValue = env->NewByteArray(pickledLength);
+                env->SetByteArrayRegion(returnValue, 0 , pickledLength, (jbyte*)pickledPtr);
             }
 
             free(pickledPtr);
@@ -891,10 +892,9 @@ JNIEXPORT jstring OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz,
         env->ThrowNew(env->FindClass("java/lang/Exception"), errorMessage);
     }
 
-    return pickledDataRetValue;
+    return returnValue;
 }
 
-
 JNIEXPORT jstring OLM_SESSION_FUNC_DEF(deserializeJni)(JNIEnv *env, jobject thiz, jbyteArray aSerializedDataBuffer, jbyteArray aKeyBuffer)
 {
     OlmSession* sessionPtr = NULL;
@@ -929,7 +929,6 @@ JNIEXPORT jstring OLM_SESSION_FUNC_DEF(deserializeJni)(JNIEnv *env, jobject thiz
         size_t pickledLength = (size_t)env->GetArrayLength(aSerializedDataBuffer);
         size_t keyLength = (size_t)env->GetArrayLength(aKeyBuffer);
         LOGD(" ## deserializeJni(): pickledLength=%lu keyLength=%lu",static_cast<long unsigned int>(pickledLength), static_cast<long unsigned int>(keyLength));
-        LOGD(" ## deserializeJni(): key=%s",(char const *)keyPtr);
         LOGD(" ## deserializeJni(): pickled=%s",(char const *)pickledPtr);
 
         size_t result = olm_unpickle_session(sessionPtr,
diff --git a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.h b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.h
index 004031e..ef92395 100644
--- a/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.h
+++ b/java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.h
@@ -50,7 +50,7 @@ JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(decryptMessageJni)(JNIEnv *env, jobjec
 JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(getSessionIdentifierJni)(JNIEnv *env, jobject thiz);
 
 // serialization
-JNIEXPORT jstring OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKey);
+JNIEXPORT jbyteArray OLM_SESSION_FUNC_DEF(serializeJni)(JNIEnv *env, jobject thiz, jbyteArray aKey);
 JNIEXPORT jstring OLM_SESSION_FUNC_DEF(deserializeJni)(JNIEnv *env, jobject thiz, jbyteArray aSerializedData, jbyteArray aKey);
 
 #ifdef __cplusplus