Move the android project from /Java/Android/OlmLibSdk

9 files changed, 1904 insertions, 0 deletions

diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/CommonSerializeUtils.java b/android/olm-sdk/src/main/java/org/matrix/olm/CommonSerializeUtils.java
new file mode 100644
index 0000000..229963f
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/CommonSerializeUtils.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2016 OpenMarket Ltd
+ * Copyright 2016 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+
+/**
+ * Helper class dedicated to serialization mechanism (template method pattern).
+ */
+abstract class CommonSerializeUtils {
+    private static final String LOG_TAG = "CommonSerializeUtils";
+
+    /**
+     * Kick off the serialization mechanism.
+     * @param aOutStream output stream for serializing
+     * @throws IOException exception
+     */
+    protected void serialize(ObjectOutputStream aOutStream) throws IOException {
+        aOutStream.defaultWriteObject();
+
+        // generate serialization key
+        byte[] key = OlmUtility.getRandomKey();
+
+        // compute pickle string
+        StringBuffer errorMsg = new StringBuffer();
+        byte[] pickledData = serialize(key, errorMsg);
+
+        if(null == pickledData) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_SERIALIZATION, String.valueOf(errorMsg));
+        } else {
+            aOutStream.writeObject(new String(key, "UTF-8"));
+            aOutStream.writeObject(new String(pickledData, "UTF-8"));
+        }
+    }
+
+    /**
+     * Kick off the deserialization mechanism.
+     * @param aInStream input stream
+     * @throws Exception the exception
+     */
+    protected void deserialize(ObjectInputStream aInStream) throws Exception {
+        aInStream.defaultReadObject();
+
+        String keyAsString = (String)aInStream.readObject();
+        String pickledDataAsString = (String)aInStream.readObject();
+
+        byte[] key;
+        byte[] pickledData;
+
+        try {
+            key = keyAsString.getBytes("UTF-8");
+            pickledData = pickledDataAsString.getBytes("UTF-8");
+
+            deserialize(pickledData, key);
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_DESERIALIZATION, e.getMessage());
+        }
+
+        Log.d(LOG_TAG,"## deserializeObject(): success");
+    }
+
+    protected abstract byte[] serialize(byte[] aKey, StringBuffer aErrorMsg);
+    protected abstract void deserialize(byte[] aSerializedData, byte[] aKey) throws Exception;
+}
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java
new file mode 100644
index 0000000..26c3e60
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java
@@ -0,0 +1,415 @@
+/*
+ * Copyright 2017 OpenMarket Ltd
+ * Copyright 2017 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.json.JSONObject;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.util.Map;
+
+/**
+ * Account class used to create Olm sessions in conjunction with {@link OlmSession} class.<br>
+ * OlmAccount provides APIs to retrieve the Olm keys.
+ *<br><br>Detailed implementation guide is available at <a href="http://matrix.org/docs/guides/e2e_implementation.html">Implementing End-to-End Encryption in Matrix clients</a>.
+ */
+public class OlmAccount extends CommonSerializeUtils implements Serializable {
+    private static final long serialVersionUID = 3497486121598434824L;
+    private static final String LOG_TAG = "OlmAccount";
+
+    // JSON keys used in the JSON objects returned by JNI
+    /** As well as the identity key, each device creates a number of Curve25519 key pairs which are
+     also used to establish Olm sessions, but can only be used once. Once again, the private part
+     remains on the device. but the public part is published to the Matrix network **/
+    public static final String JSON_KEY_ONE_TIME_KEY = "curve25519";
+
+    /** Curve25519 identity key is a public-key cryptographic system which can be used to establish a shared
+     secret.<br>In Matrix, each device has a long-lived Curve25519 identity key which is used to establish
+     Olm sessions with that device. The private key should never leave the device, but the
+     public part is signed with the Ed25519 fingerprint key ({@link #JSON_KEY_FINGER_PRINT_KEY}) and published to the network. **/
+    public static final String JSON_KEY_IDENTITY_KEY = "curve25519";
+
+    /** Ed25519 finger print is a public-key cryptographic system for signing messages.<br>In Matrix, each device has
+     an Ed25519 key pair which serves to identify that device. The private the key should
+     never leave the device, but the public part is published to the Matrix network. **/
+    public static final String JSON_KEY_FINGER_PRINT_KEY = "ed25519";
+
+    /** Account Id returned by JNI.
+     * This value identifies uniquely the native account instance.
+     */
+    private transient long mNativeId;
+
+    public OlmAccount() throws OlmException {
+        try {
+            mNativeId = createNewAccountJni();
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_INIT_ACCOUNT_CREATION, e.getMessage());
+        }
+    }
+
+    /**
+     * Create a new account and return it to JAVA side.<br>
+     * Since a C prt is returned as a jlong, special care will be taken
+     * to make the cast (OlmAccount* to jlong) platform independent.
+     * @return the initialized OlmAccount* instance or throw an exception if fails
+     **/
+    private native long createNewAccountJni();
+
+    /**
+     * Getter on the account ID.
+     * @return native account ID
+     */
+    long getOlmAccountId(){
+        return mNativeId;
+    }
+
+    /**
+     * Release native account and invalid its JAVA reference counter part.<br>
+     * Public API for {@link #releaseAccountJni()}.
+     */
+    public void releaseAccount() {
+        if (0 != mNativeId) {
+            releaseAccountJni();
+        }
+        mNativeId = 0;
+    }
+
+    /**
+     * Destroy the corresponding OLM account native object.<br>
+     * This method must ALWAYS be called when this JAVA instance
+     * is destroyed (ie. garbage collected) to prevent memory leak in native side.
+     * See {@link #createNewAccountJni()}.
+     */
+    private native void releaseAccountJni();
+
+    /**
+     * Return true the object resources have been released.<br>
+     * @return true the object resources have been released
+     */
+    public boolean isReleased() {
+        return (0 == mNativeId);
+    }
+
+    /**
+     * Return the identity keys (identity and fingerprint keys) in a dictionary.<br>
+     * Public API for {@link #identityKeysJni()}.<br>
+     * Ex:<tt>
+     * {
+     *  "curve25519":"Vam++zZPMqDQM6ANKpO/uAl5ViJSHxV9hd+b0/fwRAg",
+     *  "ed25519":"+v8SOlOASFTMrX3MCKBM4iVnYoZ+JIjpNt1fi8Z9O2I"
+     * }</tt>
+     * @return identity keys dictionary if operation succeeds, null otherwise
+     * @exception OlmException the failure reason
+     */
+    public Map<String, String> identityKeys() throws OlmException {
+        JSONObject identityKeysJsonObj = null;
+
+        byte[] identityKeysBuffer;
+
+        try {
+            identityKeysBuffer = identityKeysJni();
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## identityKeys(): Failure - " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_IDENTITY_KEYS, e.getMessage());
+        }
+
+        if (null != identityKeysBuffer) {
+            try {
+                identityKeysJsonObj = new JSONObject(new String(identityKeysBuffer, "UTF-8"));
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## identityKeys(): Exception - Msg=" + e.getMessage());
+            }
+        } else {
+            Log.e(LOG_TAG, "## identityKeys(): Failure - identityKeysJni()=null");
+        }
+
+        return OlmUtility.toStringMap(identityKeysJsonObj);
+    }
+
+    /**
+     * Get the public identity keys (Ed25519 fingerprint key and Curve25519 identity key).<br>
+     * Keys are Base64 encoded.
+     * These keys must be published on the server.
+     * @return the identity keys or throw an exception if it fails
+     */
+    private native byte[] identityKeysJni();
+
+    /**
+     * Return the largest number of "one time keys" this account can store.
+     * @return the max number of "one time keys", -1 otherwise
+     */
+    public long maxOneTimeKeys() {
+        return maxOneTimeKeysJni();
+    }
+
+    /**
+     * Return the largest number of "one time keys" this account can store.
+     * @return the max number of "one time keys", -1 otherwise
+     */
+    private native long maxOneTimeKeysJni();
+
+    /**
+     * Generate a number of new one time keys.<br> If total number of keys stored
+     * by this account exceeds {@link #maxOneTimeKeys()}, the old keys are discarded.<br>
+     * The corresponding keys are retrieved by {@link #oneTimeKeys()}.
+     * @param aNumberOfKeys number of keys to generate
+     * @exception OlmException the failure reason
+     */
+    public void generateOneTimeKeys(int aNumberOfKeys) throws OlmException {
+        try {
+            generateOneTimeKeysJni(aNumberOfKeys);
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_GENERATE_ONE_TIME_KEYS, e.getMessage());
+        }
+    }
+
+    /**
+     * Generate a number of new one time keys.<br> If total number of keys stored
+     * by this account exceeds {@link #maxOneTimeKeys()}, the old keys are discarded.
+     * An exception is thrown if the operation fails.<br>
+     * @param aNumberOfKeys number of keys to generate
+     */
+    private native void generateOneTimeKeysJni(int aNumberOfKeys);
+
+    /**
+     * Return the "one time keys" in a dictionary.<br>
+     * The number of "one time keys", is specified by {@link #generateOneTimeKeys(int)}<br>
+     * Ex:<tt>
+     * { "curve25519":
+     *  {
+     *      "AAAABQ":"qefVZd8qvjOpsFzoKSAdfUnJVkIreyxWFlipCHjSQQg",
+     *      "AAAABA":"/X8szMU+p+lsTnr56wKjaLgjTMQQkCk8EIWEAilZtQ8",
+     *      "AAAAAw":"qxNxxFHzevFntaaPdT0fhhO7tc7pco4+xB/5VRG81hA",
+     *  }
+     * }</tt><br>
+     * Public API for {@link #oneTimeKeysJni()}.<br>
+     * Note: these keys are to be published on the server.
+     * @return one time keys in string dictionary.
+     * @exception OlmException the failure reason
+     */
+    public Map<String, Map<String, String>> oneTimeKeys() throws OlmException {
+        JSONObject oneTimeKeysJsonObj = null;
+        byte[] oneTimeKeysBuffer;
+
+        try {
+            oneTimeKeysBuffer = oneTimeKeysJni();
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_ONE_TIME_KEYS, e.getMessage());
+        }
+
+        if( null != oneTimeKeysBuffer) {
+            try {
+                oneTimeKeysJsonObj = new JSONObject(new String(oneTimeKeysBuffer, "UTF-8"));
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## oneTimeKeys(): Exception - Msg=" + e.getMessage());
+            }
+        } else {
+            Log.e(LOG_TAG, "## oneTimeKeys(): Failure - identityKeysJni()=null");
+        }
+
+        return OlmUtility.toStringMapMap(oneTimeKeysJsonObj);
+    }
+
+    /**
+     * Get the public parts of the unpublished "one time keys" for the account.<br>
+     * The returned data is a JSON-formatted object with the single property
+     * <tt>curve25519</tt>, which is itself an object mapping key id to
+     * base64-encoded Curve25519 key.<br>
+     * @return byte array containing the one time keys or throw an exception if it fails
+     */
+    private native byte[] oneTimeKeysJni();
+
+    /**
+     * Remove the "one time keys" that the session used from the account.
+     * @param aSession session instance
+     * @throws OlmException the failure reason
+     */
+    public void removeOneTimeKeys(OlmSession aSession) throws OlmException {
+        if (null != aSession) {
+            try {
+                removeOneTimeKeysJni(aSession.getOlmSessionId());
+            } catch (Exception e) {
+                throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_REMOVE_ONE_TIME_KEYS, e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Remove the "one time keys" that the session used from the account.
+     * An exception is thrown if the operation fails.
+     * @param aNativeOlmSessionId native session instance identifier
+     */
+    private native void removeOneTimeKeysJni(long aNativeOlmSessionId);
+
+    /**
+     * Marks the current set of "one time keys" as being published.
+     * @exception OlmException the failure reason
+     */
+    public void markOneTimeKeysAsPublished() throws OlmException {
+        try {
+            markOneTimeKeysAsPublishedJni();
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_MARK_ONE_KEYS_AS_PUBLISHED, e.getMessage());
+        }
+    }
+
+    /**
+     * Marks the current set of "one time keys" as being published.
+     * An exception is thrown if the operation fails.
+     */
+    private native void markOneTimeKeysAsPublishedJni();
+
+    /**
+     * Sign a message with the ed25519 fingerprint key for this account.<br>
+     * The signed message is returned by the method.
+     * @param aMessage message to sign
+     * @return the signed message
+     * @exception OlmException the failure reason
+     */
+    public String signMessage(String aMessage) throws OlmException {
+        String result = null;
+
+        if (null != aMessage) {
+            try {
+                byte[] utf8String = aMessage.getBytes("UTF-8");
+
+                if (null != utf8String) {
+                    byte[] signedMessage = signMessageJni(utf8String);
+
+                    if (null != signedMessage) {
+                        result = new String(signedMessage, "UTF-8");
+                    }
+                }
+            } catch (Exception e) {
+                throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_SIGN_MESSAGE, e.getMessage());
+            }
+        }
+
+        return result;
+    }
+
+    /**
+     * Sign a message with the ed25519 fingerprint key for this account.<br>
+     * The signed message is returned by the method.
+     * @param aMessage message to sign
+     * @return the signed message
+     */
+    private native byte[] signMessageJni(byte[] aMessage);
+
+    //==============================================================================================================
+    // Serialization management
+    //==============================================================================================================
+
+    /**
+     * Kick off the serialization mechanism.
+     * @param aOutStream output stream for serializing
+     * @throws IOException exception
+     */
+    private void writeObject(ObjectOutputStream aOutStream) throws IOException {
+        serialize(aOutStream);
+    }
+
+    /**
+     * Kick off the deserialization mechanism.
+     * @param aInStream input stream
+     * @throws Exception exception
+     */
+    private void readObject(ObjectInputStream aInStream) throws Exception {
+        deserialize(aInStream);
+    }
+
+    /**
+     * 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 the account as bytes buffer
+     */
+    @Override
+    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 (null ==  aKey) {
+            aErrorMsg.append("Invalid input parameters in serializeDataWithKey()");
+        } else {
+            aErrorMsg.setLength(0);
+            try {
+                pickleRetValue = serializeJni(aKey);
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## serialize() failed " + e.getMessage());
+                aErrorMsg.append(e.getMessage());
+            }
+        }
+
+        return pickleRetValue;
+    }
+
+    /**
+     * Serialize and encrypt account instance.<br>
+     * @param aKeyBuffer key used to encrypt the serialized account data
+     * @return the serialised account as bytes buffer.
+     **/
+    private native byte[] serializeJni(byte[] aKeyBuffer);
+
+    /**
+     * Loads an account from a pickled bytes buffer.<br>
+     * See {@link #serialize(byte[], StringBuffer)}
+     * @param aSerializedData bytes buffer
+     * @param aKey key used to encrypted
+     * @exception Exception the exception
+     */
+    @Override
+    protected void deserialize(byte[] aSerializedData, byte[] aKey) throws Exception {
+        String errorMsg = null;
+
+        try {
+            if ((null == aSerializedData) || (null == aKey)) {
+                Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
+                errorMsg = "invalid input parameters";
+            } else {
+                mNativeId = deserializeJni(aSerializedData, aKey);
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## deserialize() failed " + e.getMessage());
+            errorMsg = e.getMessage();
+        }
+
+        if (!TextUtils.isEmpty(errorMsg)) {
+            releaseAccount();
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_DESERIALIZATION, errorMsg);
+        }
+    }
+
+    /**
+     * Allocate a new account and initialize it with the serialisation data.<br>
+     * @param aSerializedDataBuffer the account serialisation buffer
+     * @param aKeyBuffer the key used to encrypt the serialized account data
+     * @return the deserialized account
+     **/
+    private native long deserializeJni(byte[] aSerializedDataBuffer, byte[] aKeyBuffer);
+}
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmException.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmException.java
new file mode 100644
index 0000000..b0b1a6a
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmException.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2017 OpenMarket Ltd
+ * Copyright 2017 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+import java.io.IOException;
+
+/**
+ * Exception class to identify specific Olm SDK exceptions.
+ */
+public class OlmException extends IOException {
+    // exception codes
+
+    public static final int EXCEPTION_CODE_INIT_ACCOUNT_CREATION = 10;
+
+    public static final int EXCEPTION_CODE_ACCOUNT_SERIALIZATION = 100;
+    public static final int EXCEPTION_CODE_ACCOUNT_DESERIALIZATION = 101;
+    public static final int EXCEPTION_CODE_ACCOUNT_IDENTITY_KEYS = 102;
+    public static final int EXCEPTION_CODE_ACCOUNT_GENERATE_ONE_TIME_KEYS = 103;
+    public static final int EXCEPTION_CODE_ACCOUNT_ONE_TIME_KEYS = 104;
+    public static final int EXCEPTION_CODE_ACCOUNT_REMOVE_ONE_TIME_KEYS = 105;
+    public static final int EXCEPTION_CODE_ACCOUNT_MARK_ONE_KEYS_AS_PUBLISHED = 106;
+    public static final int EXCEPTION_CODE_ACCOUNT_SIGN_MESSAGE = 107;
+
+    public static final int EXCEPTION_CODE_CREATE_INBOUND_GROUP_SESSION = 200;
+    public static final int EXCEPTION_CODE_INIT_INBOUND_GROUP_SESSION = 201;
+    public static final int EXCEPTION_CODE_INBOUND_GROUP_SESSION_IDENTIFIER = 202;
+    public static final int EXCEPTION_CODE_INBOUND_GROUP_SESSION_DECRYPT_SESSION = 203;
+
+    public static final int EXCEPTION_CODE_CREATE_OUTBOUND_GROUP_SESSION = 300;
+    public static final int EXCEPTION_CODE_INIT_OUTBOUND_GROUP_SESSION = 301;
+    public static final int EXCEPTION_CODE_OUTBOUND_GROUP_SESSION_IDENTIFIER = 302;
+    public static final int EXCEPTION_CODE_OUTBOUND_GROUP_SESSION_KEY = 303;
+    public static final int EXCEPTION_CODE_OUTBOUND_GROUP_ENCRYPT_MESSAGE = 304;
+
+    public static final int EXCEPTION_CODE_INIT_SESSION_CREATION = 400;
+    public static final int EXCEPTION_CODE_SESSION_INIT_OUTBOUND_SESSION = 401;
+    public static final int EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION = 402;
+    public static final int EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION_FROM = 403;
+    public static final int EXCEPTION_CODE_SESSION_ENCRYPT_MESSAGE = 404;
+    public static final int EXCEPTION_CODE_SESSION_DECRYPT_MESSAGE = 405;
+    public static final int EXCEPTION_CODE_SESSION_SESSION_IDENTIFIER = 406;
+
+    public static final int EXCEPTION_CODE_UTILITY_CREATION = 500;
+    public static final int EXCEPTION_CODE_UTILITY_VERIFY_SIGNATURE = 501;
+
+    // exception human readable messages
+    public static final String EXCEPTION_MSG_INVALID_PARAMS_DESERIALIZATION = "invalid de-serialized parameters";
+
+    /** exception code to be taken from: {@link #EXCEPTION_CODE_CREATE_OUTBOUND_GROUP_SESSION}, {@link #EXCEPTION_CODE_CREATE_INBOUND_GROUP_SESSION},
+     * {@link #EXCEPTION_CODE_INIT_OUTBOUND_GROUP_SESSION}, {@link #EXCEPTION_CODE_INIT_INBOUND_GROUP_SESSION}..**/
+    private final int mCode;
+
+    /** Human readable message description **/
+    private final String mMessage;
+
+    public OlmException(int aExceptionCode, String aExceptionMessage) {
+        super();
+        mCode = aExceptionCode;
+        mMessage = aExceptionMessage;
+    }
+
+    public int getExceptionCode() {
+        return mCode;
+    }
+
+    @Override
+    public String getMessage() {
+        return mMessage;
+    }
+}
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
new file mode 100644
index 0000000..571bddb
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmInboundGroupSession.java
@@ -0,0 +1,260 @@
+/*
+ * Copyright 2017 OpenMarket Ltd
+ * Copyright 2017 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+import android.text.TextUtils;
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+
+/**
+ * Class used to create an inbound <a href="http://matrix.org/docs/guides/e2e_implementation.html#handling-an-m-room-key-event">Megolm session</a>.<br>
+ * Counter part of the outbound group session {@link OlmOutboundGroupSession}, this class decrypts the messages sent by the outbound side.
+ *
+ * <br><br>Detailed implementation guide is available at <a href="http://matrix.org/docs/guides/e2e_implementation.html">Implementing End-to-End Encryption in Matrix clients</a>.
+ */
+public class OlmInboundGroupSession extends CommonSerializeUtils implements Serializable {
+    private static final long serialVersionUID = -772028491251653253L;
+    private static final String LOG_TAG = "OlmInboundGroupSession";
+
+    /** Session Id returned by JNI.<br>
+     * This value uniquely identifies the native inbound group session instance.
+     */
+    private transient long mNativeId;
+
+    /**
+     * Result in {@link #decryptMessage(String)}
+     */
+    public static class DecryptMessageResult {
+        /** decrypt message **/
+        public String mDecryptedMessage;
+
+        /** decrypt index **/
+        public long mIndex;
+    }
+
+    /**
+     * Constructor.<br>
+     * Create and save a new native session instance ID and start a new inbound group session.
+     * The session key parameter is retrieved from an outbound group session.
+     * @param aSessionKey session key
+     * @throws OlmException constructor failure
+     */
+    public OlmInboundGroupSession(String aSessionKey) throws OlmException {
+        if (TextUtils.isEmpty(aSessionKey)) {
+            Log.e(LOG_TAG, "## initInboundGroupSession(): invalid session key");
+            throw new OlmException(OlmException.EXCEPTION_CODE_INIT_INBOUND_GROUP_SESSION, "invalid session key");
+        } else {
+            try {
+                mNativeId = createNewSessionJni(aSessionKey.getBytes("UTF-8"));
+            } catch (Exception e) {
+                throw new OlmException(OlmException.EXCEPTION_CODE_INIT_INBOUND_GROUP_SESSION, e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Initialize a new inbound group session and return it to JAVA side.<br>
+     * Since a C prt is returned as a jlong, special care will be taken
+     * to make the cast (OlmInboundGroupSession* to jlong) platform independent.
+     * @param aSessionKeyBuffer session key from an outbound session
+     * @return the initialized OlmInboundGroupSession* instance or throw an exception it fails.
+     **/
+    private native long createNewSessionJni(byte[] aSessionKeyBuffer);
+
+    /**
+     * Release native session and invalid its JAVA reference counter part.<br>
+     * Public API for {@link #releaseSessionJni()}.
+     */
+    public void releaseSession(){
+        if (0 != mNativeId) {
+            releaseSessionJni();
+        }
+        mNativeId = 0;
+    }
+
+    /**
+     * Destroy the corresponding OLM inbound group session native object.<br>
+     * This method must ALWAYS be called when this JAVA instance
+     * is destroyed (ie. garbage collected) to prevent memory leak in native side.
+     * See {@link #createNewSessionJni(byte[])}.
+     */
+    private native void releaseSessionJni();
+
+    /**
+     * Return true the object resources have been released.<br>
+     * @return true the object resources have been released
+     */
+    public boolean isReleased() {
+        return (0 == mNativeId);
+    }
+
+    /**
+     * 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 {
+            return new String(sessionIdentifierJni(), "UTF-8");
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## sessionIdentifier() failed " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_INBOUND_GROUP_SESSION_IDENTIFIER, e.getMessage());
+        }
+    }
+
+    /**
+     * Get a base64-encoded identifier for this inbound group session.
+     * An exception is thrown if the operation fails.
+     * @return the base64-encoded identifier
+     */
+    private native byte[] sessionIdentifierJni();
+
+    /**
+     * Decrypt the message passed in parameter.<br>
+     * In case of error, null is returned and an error message description is provided in aErrorMsg.
+     * @param aEncryptedMsg the message to be decrypted
+     * @return the decrypted message information
+     * @exception OlmException teh failure reason
+     */
+    public DecryptMessageResult decryptMessage(String aEncryptedMsg) throws OlmException {
+        DecryptMessageResult result = new DecryptMessageResult();
+
+        try {
+            byte[] decryptedMessageBuffer = decryptMessageJni(aEncryptedMsg.getBytes("UTF-8"), result);
+
+            if (null != decryptedMessageBuffer) {
+                result.mDecryptedMessage = new String(decryptedMessageBuffer, "UTF-8");
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## decryptMessage() failed " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_INBOUND_GROUP_SESSION_DECRYPT_SESSION, e.getMessage());
+        }
+
+        return result;
+    }
+
+    /**
+     * Decrypt a message.
+     * An exception is thrown if the operation fails.
+     * @param aEncryptedMsg the encrypted message
+     * @param aDecryptMessageResult the decryptMessage informaton
+     * @return the decrypted message
+     */
+    private native byte[] decryptMessageJni(byte[] aEncryptedMsg, DecryptMessageResult aDecryptMessageResult);
+
+    //==============================================================================================================
+    // Serialization management
+    //==============================================================================================================
+
+    /**
+     * Kick off the serialization mechanism.
+     * @param aOutStream output stream for serializing
+     * @throws IOException exception
+     */
+    private void writeObject(ObjectOutputStream aOutStream) throws IOException {
+        serialize(aOutStream);
+    }
+
+    /**
+     * Kick off the deserialization mechanism.
+     * @param aInStream input stream
+     * @throws Exception exception
+     */
+    private void readObject(ObjectInputStream aInStream) throws Exception {
+        deserialize(aInStream);
+    }
+
+    /**
+     * 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 bytes buffer if operation succeed, null otherwise
+     */
+    @Override
+    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 (null == aKey) {
+            aErrorMsg.append("Invalid input parameters in serialize()");
+        } else {
+            aErrorMsg.setLength(0);
+            try {
+                pickleRetValue = serializeJni(aKey);
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## serialize() failed " + e.getMessage());
+                aErrorMsg.append(e.getMessage());
+            }
+        }
+
+        return pickleRetValue;
+    }
+    /**
+     * JNI counter part of {@link #serialize(byte[], StringBuffer)}.
+     * @param aKey encryption key
+     * @return the serialized session
+     */
+    private native byte[] serializeJni(byte[] aKey);
+
+    /**
+     * Loads an account from a pickled base64 string.<br>
+     * See {@link #serialize(byte[], StringBuffer)}
+     * @param aSerializedData pickled account in a bytes buffer
+     * @param aKey key used to encrypted
+     */
+    @Override
+    protected void deserialize(byte[] aSerializedData, byte[] aKey) throws Exception {
+        String errorMsg = null;
+
+        try {
+            if ((null == aSerializedData) || (null == aKey)) {
+                Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
+                errorMsg = "invalid input parameters";
+            } else {
+                mNativeId = deserializeJni(aSerializedData, aKey);
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## deserialize() failed " + e.getMessage());
+            errorMsg = e.getMessage();
+        }
+
+        if (!TextUtils.isEmpty(errorMsg)) {
+            releaseSession();
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_DESERIALIZATION, errorMsg);
+        }
+    }
+
+    /**
+     * Allocate a new session and initialize it with the serialisation data.<br>
+     * An exception is thrown if the operation fails.
+     * @param aSerializedData the session serialisation buffer
+     * @param aKey the key used to encrypt the serialized account data
+     * @return the deserialized session
+     **/
+    private native long deserializeJni(byte[] aSerializedData, byte[] aKey);
+}
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmManager.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmManager.java
new file mode 100644
index 0000000..c1e6031
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmManager.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2016 OpenMarket Ltd
+ * Copyright 2016 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+import android.content.Context;
+import android.util.Log;
+
+/**
+ * Olm SDK entry point class.<br> An OlmManager instance must be created at first to enable native library load.
+ * <br><br>Detailed implementation guide is available at <a href="http://matrix.org/docs/guides/e2e_implementation.html">Implementing End-to-End Encryption in Matrix clients</a>.
+ */
+public class OlmManager {
+    private static final String LOG_TAG = "OlmManager";
+
+    /**
+     * Constructor.
+     */
+    public OlmManager() {
+    }
+
+    static {
+        try {
+            java.lang.System.loadLibrary("olm");
+        } catch(UnsatisfiedLinkError e) {
+            Log.e(LOG_TAG,"Exception loadLibrary() - Msg="+e.getMessage());
+        }
+    }
+
+    /**
+     * Provide the android library version
+     * @param context the context
+     * @return the library version
+     */
+    public String getSdkOlmVersion(Context context) {
+        String gitVersion = context.getResources().getString(R.string.git_olm_revision);
+        String date = context.getResources().getString(R.string.git_olm_revision_date);
+        return gitVersion + "-" + date;
+    }
+
+    /**
+     * Get the OLM lib version.
+     * @return the lib version as a string
+     */
+    public String getOlmLibVersion(){
+        return getOlmLibVersionJni();
+    }
+    public native String getOlmLibVersionJni();
+}
+
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmMessage.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmMessage.java
new file mode 100644
index 0000000..08db993
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmMessage.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2016 OpenMarket Ltd
+ * Copyright 2016 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+/**
+ * Message class used in Olm sessions to contain the encrypted data.<br>
+ * See {@link OlmSession#decryptMessage(OlmMessage)} and {@link OlmSession#encryptMessage(String)}.
+ * <br>Detailed implementation guide is available at <a href="http://matrix.org/docs/guides/e2e_implementation.html">Implementing End-to-End Encryption in Matrix clients</a>.
+ */
+public class OlmMessage {
+    /** PRE KEY message type (used to establish new Olm session) **/
+    public final static int MESSAGE_TYPE_PRE_KEY = 0;
+    /** normal message type **/
+    public final static int MESSAGE_TYPE_MESSAGE = 1;
+
+    /** the encrypted message **/
+    public String mCipherText;
+
+    /** defined by {@link #MESSAGE_TYPE_MESSAGE} or {@link #MESSAGE_TYPE_PRE_KEY}**/
+    public long mType;
+}
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java
new file mode 100644
index 0000000..0481824
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmOutboundGroupSession.java
@@ -0,0 +1,289 @@
+/*
+ * Copyright 2017 OpenMarket Ltd
+ * Copyright 2017 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+
+import android.text.TextUtils;
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+
+/**
+ * Class used to create an outbound a <a href="http://matrix.org/docs/guides/e2e_implementation.html#starting-a-megolm-session">Megolm session</a>.<br>
+ * To send a first message in an encrypted room, the client should start a new outbound Megolm session.
+ * The session ID and the session key must be shared with each device in the room within.
+ *
+ * <br><br>Detailed implementation guide is available at <a href="http://matrix.org/docs/guides/e2e_implementation.html">Implementing End-to-End Encryption in Matrix clients</a>.
+ */
+public class OlmOutboundGroupSession extends CommonSerializeUtils implements Serializable {
+    private static final long serialVersionUID = -3133097431283604416L;
+    private static final String LOG_TAG = "OlmOutboundGroupSession";
+
+    /** Session Id returned by JNI.<br>
+     * This value uniquely identifies the native outbound group session instance.
+     */
+    private transient long mNativeId;
+
+    /**
+     * Constructor.<br>
+     * Create and save a new session native instance ID and
+     * initialise a new outbound group session.<br>
+     * @throws OlmException constructor failure
+     */
+    public OlmOutboundGroupSession() throws OlmException {
+        try {
+            mNativeId = createNewSessionJni();
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_CREATE_OUTBOUND_GROUP_SESSION, e.getMessage());
+        }
+    }
+
+    /**
+     * Create the corresponding OLM outbound group session in native side.<br>
+     * An exception is thrown if the operation fails.
+     * Do not forget to call {@link #releaseSession()} when JAVA side is done.
+     * @return native session instance identifier (see {@link #mNativeId})
+     */
+    private native long createNewSessionJni();
+
+    /**
+     * Release native session and invalid its JAVA reference counter part.<br>
+     * Public API for {@link #releaseSessionJni()}.
+     */
+    public void releaseSession() {
+        if (0 != mNativeId) {
+            releaseSessionJni();
+        }
+        mNativeId = 0;
+    }
+
+    /**
+     * Destroy the corresponding OLM outbound group session native object.<br>
+     * This method must ALWAYS be called when this JAVA instance
+     * is destroyed (ie. garbage collected) to prevent memory leak in native side.
+     * See {@link #createNewSessionJni()}.
+     */
+    private native void releaseSessionJni();
+
+    /**
+     * Return true the object resources have been released.<br>
+     * @return true the object resources have been released
+     */
+    public boolean isReleased() {
+        return (0 == mNativeId);
+    }
+
+    /**
+     * Get a base64-encoded identifier for this session.
+     * @return session identifier
+     * @throws OlmException the failure reason
+     */
+    public String sessionIdentifier() throws OlmException {
+        try {
+            return new String(sessionIdentifierJni(), "UTF-8");
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## sessionIdentifier() failed " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_OUTBOUND_GROUP_SESSION_IDENTIFIER, e.getMessage());
+        }
+    }
+
+    /**
+     * Return the session identifier.
+     * An exception is thrown if the operation fails.
+     * @return the session identifier
+     */
+    private native byte[] sessionIdentifierJni();
+
+    /**
+     * Get the current message index for this session.<br>
+     * Each message is sent with an increasing index, this
+     * method returns the index for the next message.
+     * @return current session index
+     */
+    public int messageIndex() {
+        return messageIndexJni();
+    }
+
+    /**
+     * Get the current message index for this session.<br>
+     * Each message is sent with an increasing index, this
+     * method returns the index for the next message.
+     * An exception is thrown if the operation fails.
+     * @return current session index
+     */
+    private native int messageIndexJni();
+
+    /**
+     * Get the base64-encoded current ratchet key for this session.<br>
+     * Each message is sent with a different ratchet key. This method returns the
+     * ratchet key that will be used for the next message.
+     * @return outbound session key
+     * @exception OlmException the failure reason
+     */
+    public String sessionKey() throws OlmException {
+        try {
+            return new String(sessionKeyJni(), "UTF-8");
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## sessionKey() failed " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_OUTBOUND_GROUP_SESSION_KEY, e.getMessage());
+        }
+    }
+
+    /**
+     * Return the session key.
+     * An exception is thrown if the operation fails.
+     * @return the session key
+     */
+    private native byte[] sessionKeyJni();
+
+    /**
+     * Encrypt some plain-text message.<br>
+     * The message given as parameter is encrypted and returned as the return value.
+     * @param aClearMsg message to be encrypted
+     * @return the encrypted message
+     * @exception OlmException the encryption failure reason
+     */
+    public String encryptMessage(String aClearMsg) throws OlmException {
+        String retValue = null;
+
+        if (!TextUtils.isEmpty(aClearMsg)) {
+            try {
+                byte[] encryptedBuffer = encryptMessageJni(aClearMsg.getBytes("UTF-8"));
+
+                if (null != encryptedBuffer) {
+                    retValue = new String(encryptedBuffer , "UTF-8");
+                }
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## encryptMessage() failed " + e.getMessage());
+                throw new OlmException(OlmException.EXCEPTION_CODE_OUTBOUND_GROUP_ENCRYPT_MESSAGE, e.getMessage());
+            }
+        }
+
+        return retValue;
+    }
+
+    /**
+     * Encrypt a bytes buffer messages.
+     * An exception is thrown if the operation fails.
+     * @param aClearMsgBuffer  the message to encode
+     * @return the encoded message
+     */
+    private native byte[] encryptMessageJni(byte[] aClearMsgBuffer);
+
+    //==============================================================================================================
+    // Serialization management
+    //==============================================================================================================
+
+    /**
+     * Kick off the serialization mechanism.
+     * @param aOutStream output stream for serializing
+     * @throws IOException exception
+     */
+    private void writeObject(ObjectOutputStream aOutStream) throws IOException {
+        serialize(aOutStream);
+    }
+
+    /**
+     * Kick off the deserialization mechanism.
+     * @param aInStream input stream
+     * @throws Exception exception
+     */
+    private void readObject(ObjectInputStream aInStream) throws Exception {
+        deserialize(aInStream);
+    }
+
+    /**
+     * 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 bytes buffer if operation succeed, null otherwise
+     */
+    @Override
+    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 (null == aKey) {
+            aErrorMsg.append("Invalid input parameters in serialize()");
+        } else {
+            try {
+                pickleRetValue = serializeJni(aKey);
+            } catch (Exception e) {
+                Log.e(LOG_TAG,"## serialize(): failed " + e.getMessage());
+                aErrorMsg.append(e.getMessage());
+            }
+        }
+
+        return pickleRetValue;
+    }
+
+    /**
+     * JNI counter part of {@link #serialize(byte[], StringBuffer)}.
+     * An exception is thrown if the operation fails.
+     * @param aKey encryption key
+     * @return the serialized session
+     */
+    private native byte[] serializeJni(byte[] aKey);
+
+    /**
+     * Loads an account from a pickled base64 string.<br>
+     * See {@link #serialize(byte[], StringBuffer)}
+     * @param aSerializedData pickled account in a base64 bytes buffer
+     * @param aKey key used to encrypted
+     * @exception Exception the exception
+     */
+    @Override
+    protected void deserialize(byte[] aSerializedData, byte[] aKey) throws Exception {
+        String errorMsg = null;
+
+        try {
+            if ((null == aSerializedData) || (null == aKey)) {
+                Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
+                errorMsg = "invalid input parameters";
+            } else {
+                mNativeId = deserializeJni(aSerializedData, aKey);
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## deserialize() failed " + e.getMessage());
+            errorMsg = e.getMessage();
+        }
+
+        if (!TextUtils.isEmpty(errorMsg)) {
+            releaseSession();
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_DESERIALIZATION, errorMsg);
+        }
+    }
+
+    /**
+     * Allocate a new session and initialize it with the serialisation data.<br>
+     * An exception is thrown if the operation fails.
+     * @param aSerializedData the session serialisation buffer
+     * @param aKey the key used to encrypt the serialized account data
+     * @return the deserialized session
+     **/
+    private native long deserializeJni(byte[] aSerializedData, byte[] aKey);
+
+}
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
new file mode 100644
index 0000000..da2e963
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmSession.java
@@ -0,0 +1,445 @@
+/*
+ * Copyright 2016 OpenMarket Ltd
+ * Copyright 2016 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+import android.text.TextUtils;
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+
+/**
+ * Session class used to create Olm sessions in conjunction with {@link OlmAccount} class.<br>
+ * Olm session is used to encrypt data between devices, especially to create Olm group sessions (see {@link OlmOutboundGroupSession} and {@link OlmInboundGroupSession}).<br>
+ * To establish an Olm session with Bob, Alice calls {@link #initOutboundSession(OlmAccount, String, String)} with Bob's identity and onetime keys. Then Alice generates an encrypted PRE_KEY message ({@link #encryptMessage(String)})
+ * used by Bob to open the Olm session in his side with {@link #initOutboundSession(OlmAccount, String, String)}.
+ * From this step on, messages can be exchanged by using {@link #encryptMessage(String)} and {@link #decryptMessage(OlmMessage)}.
+ * <br><br>Detailed implementation guide is available at <a href="http://matrix.org/docs/guides/e2e_implementation.html">Implementing End-to-End Encryption in Matrix clients</a>.
+ */
+public class OlmSession extends CommonSerializeUtils implements Serializable {
+    private static final long serialVersionUID = -8975488639186976419L;
+    private static final String LOG_TAG = "OlmSession";
+
+    /** Session Id returned by JNI.
+     * This value uniquely identifies the native session instance.
+     **/
+    private transient long mNativeId;
+
+    public OlmSession() throws OlmException {
+        try {
+            mNativeId = createNewSessionJni();
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_INIT_SESSION_CREATION, e.getMessage());
+        }
+    }
+
+    /**
+     * Create an OLM session in native side.<br>
+     * Do not forget to call {@link #releaseSession()} when JAVA side is done.
+     * @return native account instance identifier or throw an exception.
+     */
+    private native long createNewSessionJni();
+
+    /**
+     * Getter on the session ID.
+     * @return native session ID
+     */
+    long getOlmSessionId(){
+        return mNativeId;
+    }
+
+    /**
+     * Destroy the corresponding OLM session native object.<br>
+     * This method must ALWAYS be called when this JAVA instance
+     * is destroyed (ie. garbage collected) to prevent memory leak in native side.
+     * See {@link #createNewSessionJni()}.
+     */
+    private native void releaseSessionJni();
+
+    /**
+     * Release native session and invalid its JAVA reference counter part.<br>
+     * Public API for {@link #releaseSessionJni()}.
+     */
+    public void releaseSession() {
+        if (0 != mNativeId) {
+            releaseSessionJni();
+        }
+        mNativeId = 0;
+    }
+
+    /**
+     * Return true the object resources have been released.<br>
+     * @return true the object resources have been released
+     */
+    public boolean isReleased() {
+        return (0 == mNativeId);
+    }
+
+    /**
+     * Creates a new out-bound session for sending messages to a recipient
+     * identified by an identity key and a one time key.<br>
+     * @param aAccount the account to associate with this session
+     * @param aTheirIdentityKey the identity key of the recipient
+     * @param aTheirOneTimeKey the one time key of the recipient
+     * @exception OlmException the failure reason
+     */
+    public void initOutboundSession(OlmAccount aAccount, String aTheirIdentityKey, String aTheirOneTimeKey) throws OlmException {
+        if ((null == aAccount) || TextUtils.isEmpty(aTheirIdentityKey) || TextUtils.isEmpty(aTheirOneTimeKey)) {
+            Log.e(LOG_TAG, "## initOutboundSession(): invalid input parameters");
+            throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_OUTBOUND_SESSION, "invalid input parameters");
+        } else {
+            try {
+                initOutboundSessionJni(aAccount.getOlmAccountId(), aTheirIdentityKey.getBytes("UTF-8"), aTheirOneTimeKey.getBytes("UTF-8"));
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## initOutboundSession(): " + e.getMessage());
+                throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_OUTBOUND_SESSION, e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Create a new in-bound session for sending/receiving messages from an
+     * incoming PRE_KEY message.<br> The recipient is defined as the entity
+     * with whom the session is established.
+     * An exception is thrown if the operation fails.
+     * @param aOlmAccountId account instance
+     * @param aTheirIdentityKey the identity key of the recipient
+     * @param aTheirOneTimeKey the one time key of the recipient
+     **/
+    private native void initOutboundSessionJni(long aOlmAccountId, byte[] aTheirIdentityKey, byte[] aTheirOneTimeKey);
+
+    /**
+     * Create a new in-bound session for sending/receiving messages from an
+     * incoming PRE_KEY message ({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}).<br>
+     * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
+     * @param aAccount the account to associate with this session
+     * @param aPreKeyMsg PRE KEY message
+     * @exception OlmException the failure reason
+     */
+    public void initInboundSession(OlmAccount aAccount, String aPreKeyMsg) throws OlmException {
+        if ((null == aAccount) || TextUtils.isEmpty(aPreKeyMsg)){
+            Log.e(LOG_TAG, "## initInboundSession(): invalid input parameters");
+            throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION, "invalid input parameters");
+        } else {
+            try {
+                initInboundSessionJni(aAccount.getOlmAccountId(), aPreKeyMsg.getBytes("UTF-8"));
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## initInboundSession(): " + e.getMessage());
+                throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION, e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Create a new in-bound session for sending/receiving messages from an
+     * incoming PRE_KEY message.<br>
+     * An exception is thrown if the operation fails.
+     * @param aOlmAccountId account instance
+     * @param aOneTimeKeyMsg PRE_KEY message
+     */
+    private native void initInboundSessionJni(long aOlmAccountId, byte[] aOneTimeKeyMsg);
+
+    /**
+     * Create a new in-bound session for sending/receiving messages from an
+     * incoming PRE_KEY({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}) message based on the sender identity key.<br>
+     * Public API for {@link #initInboundSessionFromIdKeyJni(long, byte[], byte[])}.
+     * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
+     * This method must only be called the first time a pre-key message is received from an inbound session.
+     * @param aAccount the account to associate with this session
+     * @param aTheirIdentityKey the sender identity key
+     * @param aPreKeyMsg PRE KEY message
+     * @exception OlmException the failure reason
+     */
+    public void initInboundSessionFrom(OlmAccount aAccount, String aTheirIdentityKey, String aPreKeyMsg) throws OlmException {
+        if ( (null==aAccount) || TextUtils.isEmpty(aPreKeyMsg)){
+            Log.e(LOG_TAG, "## initInboundSessionFrom(): invalid input parameters");
+            throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION_FROM, "invalid input parameters");
+        } else {
+            try {
+                initInboundSessionFromIdKeyJni(aAccount.getOlmAccountId(), aTheirIdentityKey.getBytes("UTF-8"), aPreKeyMsg.getBytes("UTF-8"));
+            } catch (Exception e) {
+                Log.e(LOG_TAG, "## initInboundSessionFrom(): " + e.getMessage());
+                throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_INIT_INBOUND_SESSION_FROM, e.getMessage());
+            }
+        }
+    }
+
+    /**
+     * Create a new in-bound session for sending/receiving messages from an
+     * incoming PRE_KEY message based on the recipient identity key.<br>
+     * An exception is thrown if the operation fails.
+     * @param aOlmAccountId account instance
+     * @param aTheirIdentityKey the identity key of the recipient
+     * @param aOneTimeKeyMsg encrypted message
+     */
+    private native void initInboundSessionFromIdKeyJni(long aOlmAccountId, byte[] aTheirIdentityKey, byte[] aOneTimeKeyMsg);
+
+    /**
+     * Get the session identifier.<br> Will be the same for both ends of the
+     * conversation. The session identifier is returned as a String object.
+     * Session Id sample: "session_id":"M4fOVwD6AABrkTKl"
+     * Public API for {@link #getSessionIdentifierJni()}.
+     * @return the session ID
+     * @exception OlmException the failure reason
+     */
+    public String sessionIdentifier() throws OlmException {
+        try {
+            byte[] buffer = getSessionIdentifierJni();
+
+            if (null != buffer) {
+                return new String(buffer, "UTF-8");
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## sessionIdentifier(): " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_SESSION_IDENTIFIER, e.getMessage());
+        }
+
+        return null;
+    }
+
+    /**
+     * Get the session identifier for this session.
+     * An exception is thrown if the operation fails.
+     * @return the session identifier
+     */
+    private native byte[] getSessionIdentifierJni();
+
+    /**
+     * Checks if the PRE_KEY({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}) message is for this in-bound session.<br>
+     * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
+     * Public API for {@link #matchesInboundSessionJni(byte[])}.
+     * @param aOneTimeKeyMsg PRE KEY message
+     * @return true if the one time key matches.
+     */
+    public boolean matchesInboundSession(String aOneTimeKeyMsg) {
+        boolean retCode = false;
+
+        try {
+            retCode = matchesInboundSessionJni(aOneTimeKeyMsg.getBytes("UTF-8"));
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## matchesInboundSession(): failed " + e.getMessage());
+        }
+
+        return retCode;
+    }
+
+    /**
+     * Checks if the PRE_KEY message is for this in-bound session.<br>
+     * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
+     * An exception is thrown if the operation fails.
+     * @param aOneTimeKeyMsg PRE KEY message
+     * @return true if the PRE_KEY message matches
+     */
+    private native boolean matchesInboundSessionJni(byte[] aOneTimeKeyMsg);
+
+    /**
+     * Checks if the PRE_KEY({@link OlmMessage#MESSAGE_TYPE_PRE_KEY}) message is for this in-bound session based on the sender identity key.<br>
+     * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
+     * Public API for {@link #matchesInboundSessionJni(byte[])}.
+     * @param aTheirIdentityKey the sender identity key
+     * @param aOneTimeKeyMsg PRE KEY message
+     * @return this if operation succeed, null otherwise
+     */
+    public boolean matchesInboundSessionFrom(String aTheirIdentityKey, String aOneTimeKeyMsg) {
+        boolean retCode = false;
+
+        try {
+            retCode = matchesInboundSessionFromIdKeyJni(aTheirIdentityKey.getBytes("UTF-8"), aOneTimeKeyMsg.getBytes("UTF-8"));
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## matchesInboundSessionFrom(): failed " + e.getMessage());
+        }
+
+        return retCode;
+    }
+
+    /**
+     * Checks if the PRE_KEY message is for this in-bound session based on the sender identity key.<br>
+     * This API may be used to process a "m.room.encrypted" event when type = 1 (PRE_KEY).
+     * An exception is thrown if the operation fails.
+     * @param aTheirIdentityKey the identity key of the sender
+     * @param aOneTimeKeyMsg PRE KEY message
+     * @return true if the PRE_KEY message matches.
+     */
+    private native boolean matchesInboundSessionFromIdKeyJni(byte[] aTheirIdentityKey, byte[] aOneTimeKeyMsg);
+
+    /**
+     * Encrypt a message using the session.<br>
+     * The encrypted message is returned in a OlmMessage object.
+     * Public API for {@link #encryptMessageJni(byte[], OlmMessage)}.
+     * @param aClearMsg message to encrypted
+     * @return the encrypted message
+     * @exception OlmException the failure reason
+     */
+    public OlmMessage encryptMessage(String aClearMsg) throws OlmException {
+        if (null == aClearMsg) {
+            return null;
+        }
+
+        OlmMessage encryptedMsgRetValue = new OlmMessage();
+
+        try {
+            byte[] encryptedMessageBuffer = encryptMessageJni(aClearMsg.getBytes("UTF-8"), encryptedMsgRetValue);
+
+            if (null != encryptedMessageBuffer) {
+                encryptedMsgRetValue.mCipherText = new String(encryptedMessageBuffer, "UTF-8");
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## encryptMessage(): failed " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_ENCRYPT_MESSAGE, e.getMessage());
+        }
+
+        return encryptedMsgRetValue;
+    }
+
+    /**
+     * Encrypt a message using the session.<br>
+     * An exception is thrown if the operation fails.
+     * @param aClearMsg clear text message
+     * @param aEncryptedMsg ciphered message
+     * @return the encrypted message
+     */
+    private native byte[] encryptMessageJni(byte[] aClearMsg, OlmMessage aEncryptedMsg);
+
+    /**
+     * Decrypt a message using the session.<br>
+     * The encrypted message is given as a OlmMessage object.
+     * @param aEncryptedMsg message to decrypt
+     * @return the decrypted message
+     * @exception OlmException the failure reason
+     */
+    public String decryptMessage(OlmMessage aEncryptedMsg) throws OlmException {
+        if (null == aEncryptedMsg) {
+            return null;
+        }
+
+        try {
+            return new String(decryptMessageJni(aEncryptedMsg), "UTF-8");
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## decryptMessage(): failed " + e.getMessage());
+            throw new OlmException(OlmException.EXCEPTION_CODE_SESSION_DECRYPT_MESSAGE, e.getMessage());
+        }
+    }
+    /**
+     * Decrypt a message using the session.<br>
+     * An exception is thrown if the operation fails.
+     * @param aEncryptedMsg message to decrypt
+     * @return the decrypted message
+     */
+    private native byte[] decryptMessageJni(OlmMessage aEncryptedMsg);
+
+    //==============================================================================================================
+    // Serialization management
+    //==============================================================================================================
+
+    /**
+     * Kick off the serialization mechanism.
+     * @param aOutStream output stream for serializing
+     * @throws IOException exception
+     */
+    private void writeObject(ObjectOutputStream aOutStream) throws IOException {
+        serialize(aOutStream);
+    }
+
+    /**
+     * Kick off the deserialization mechanism.
+     * @param aInStream input stream
+     * @throws IOException exception
+     * @throws ClassNotFoundException exception
+     */
+    private void readObject(ObjectInputStream aInStream) throws Exception {
+        deserialize(aInStream);
+    }
+
+    /**
+     * 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 session as a bytes buffer
+     */
+    @Override
+    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 (null == aKey) {
+            aErrorMsg.append("Invalid input parameters in serializeDataWithKey()");
+        } else {
+            aErrorMsg.setLength(0);
+            try {
+                pickleRetValue = serializeJni(aKey);
+            } catch (Exception e) {
+                Log.e(LOG_TAG,"## serializeDataWithKey(): failed " + e.getMessage());
+                aErrorMsg.append(e.getMessage());
+            }
+        }
+
+        return pickleRetValue;
+    }
+
+    /**
+     * Serialize and encrypt session instance.<br>
+     * An exception is thrown if the operation fails.
+     * @param aKeyBuffer key used to encrypt the serialized account data
+     * @return the serialised account as bytes buffer.
+     **/
+    private native byte[] serializeJni(byte[] aKeyBuffer);
+
+    /**
+     * Loads an account from a pickled base64 string.<br>
+     * See {@link #serialize(byte[], StringBuffer)}
+     * @param aSerializedData pickled account in a base64 string format
+     * @param aKey key used to encrypted
+     */
+    @Override
+    protected void deserialize(byte[] aSerializedData, byte[] aKey) throws Exception {
+        String errorMsg = null;
+
+        try {
+            if ((null == aSerializedData) || (null == aKey)) {
+                Log.e(LOG_TAG, "## deserialize(): invalid input parameters");
+                errorMsg = "invalid input parameters";
+            } else {
+                mNativeId = deserializeJni(aSerializedData, aKey);
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## deserialize() failed " + e.getMessage());
+            errorMsg = e.getMessage();
+        }
+
+        if (!TextUtils.isEmpty(errorMsg)) {
+            releaseSession();
+            throw new OlmException(OlmException.EXCEPTION_CODE_ACCOUNT_DESERIALIZATION, errorMsg);
+        }
+    }
+    /**
+     * Allocate a new session and initialize it with the serialisation data.<br>
+     * An exception is thrown if the operation fails.
+     * @param aSerializedData the session serialisation buffer
+     * @param aKey the key used to encrypt the serialized account data
+     * @return the deserialized session
+     **/
+    private native long deserializeJni(byte[] aSerializedData, byte[] aKey);
+}
+
diff --git a/android/olm-sdk/src/main/java/org/matrix/olm/OlmUtility.java b/android/olm-sdk/src/main/java/org/matrix/olm/OlmUtility.java
new file mode 100644
index 0000000..bf9ef90
--- /dev/null
+++ b/android/olm-sdk/src/main/java/org/matrix/olm/OlmUtility.java
@@ -0,0 +1,227 @@
+/*
+ * Copyright 2017 OpenMarket Ltd
+ * Copyright 2017 Vector Creations Ltd
+ *
+ * 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 org.matrix.olm;
+
+import android.text.TextUtils;
+import android.util.Log;
+
+import org.json.JSONObject;
+
+import java.security.SecureRandom;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+/**
+ * Olm SDK helper class.
+ */
+public class OlmUtility {
+    private static final String LOG_TAG = "OlmUtility";
+
+    public static final int RANDOM_KEY_SIZE = 32;
+
+    /** Instance Id returned by JNI.
+     * This value uniquely identifies this utility instance.
+     **/
+    private long mNativeId;
+
+    public OlmUtility() throws OlmException  {
+        initUtility();
+    }
+
+    /**
+     * Create a native utility instance.
+     * To be called before any other API call.
+     * @exception OlmException the exception
+     */
+    private void initUtility() throws OlmException {
+        try {
+            mNativeId = createUtilityJni();
+        } catch (Exception e) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_UTILITY_CREATION, e.getMessage());
+        }
+    }
+
+    private native long createUtilityJni();
+
+    /**
+     * Release native instance.<br>
+     * Public API for {@link #releaseUtilityJni()}.
+     */
+    public void releaseUtility() {
+        if (0 != mNativeId) {
+            releaseUtilityJni();
+        }
+        mNativeId = 0;
+    }
+    private native void releaseUtilityJni();
+
+    /**
+     * Verify an ed25519 signature.<br>
+     * An exception is thrown if the operation fails.
+     * @param aSignature the base64-encoded message signature to be checked.
+     * @param aFingerprintKey the ed25519 key (fingerprint key)
+     * @param aMessage the signed message
+     * @exception OlmException the failure reason
+     */
+    public void verifyEd25519Signature(String aSignature, String aFingerprintKey, String aMessage) throws OlmException {
+        String errorMessage;
+
+        try {
+            if (TextUtils.isEmpty(aSignature) || TextUtils.isEmpty(aFingerprintKey) || TextUtils.isEmpty(aMessage)) {
+                Log.e(LOG_TAG, "## verifyEd25519Signature(): invalid input parameters");
+                errorMessage = "JAVA sanity check failure - invalid input parameters";
+            } else {
+                errorMessage =  verifyEd25519SignatureJni(aSignature.getBytes("UTF-8"), aFingerprintKey.getBytes("UTF-8"), aMessage.getBytes("UTF-8"));
+            }
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "## verifyEd25519Signature(): failed " + e.getMessage());
+            errorMessage = e.getMessage();
+        }
+
+        if (!TextUtils.isEmpty(errorMessage)) {
+            throw new OlmException(OlmException.EXCEPTION_CODE_UTILITY_VERIFY_SIGNATURE, errorMessage);
+        }
+    }
+
+    /**
+     * Verify an ed25519 signature.
+     * Return a human readable error message in case of verification failure.
+     * @param aSignature the base64-encoded message signature to be checked.
+     * @param aFingerprintKey the ed25519 key
+     * @param aMessage the signed message
+     * @return null if validation succeed, the error message string if operation failed
+     */
+    private native String verifyEd25519SignatureJni(byte[] aSignature, byte[] aFingerprintKey, byte[] aMessage);
+
+    /**
+     * Compute the hash(SHA-256) value of the string given in parameter(aMessageToHash).<br>
+     * The hash value is the returned by the method.
+     * @param aMessageToHash message to be hashed
+     * @return hash value if operation succeed, null otherwise
+     */
+     public String sha256(String aMessageToHash) {
+         String hashRetValue = null;
+
+         if (null != aMessageToHash) {
+             try {
+                 hashRetValue = new String(sha256Jni(aMessageToHash.getBytes("UTF-8")), "UTF-8");
+             } catch (Exception e) {
+                 Log.e(LOG_TAG, "## sha256(): failed " + e.getMessage());
+             }
+         }
+
+        return hashRetValue;
+    }
+
+    /**
+     * Compute the digest (SHA 256) for the message passed in parameter.<br>
+     * The digest value is the function return value.
+     * An exception is thrown if the operation fails.
+     * @param aMessage the message
+     * @return digest of the message.
+     **/
+    private native byte[] sha256Jni(byte[] aMessage);
+
+    /**
+     * Helper method to compute a string based on random integers.
+     * @return bytes buffer containing randoms integer values
+     */
+    public static byte[] getRandomKey() {
+        SecureRandom secureRandom = new SecureRandom();
+        byte[] buffer = new byte[RANDOM_KEY_SIZE];
+        secureRandom.nextBytes(buffer);
+
+        // the key is saved as string
+        // so avoid the UTF8 marker bytes
+        for(int i = 0; i < RANDOM_KEY_SIZE; i++) {
+            buffer[i] = (byte)(buffer[i] & 0x7F);
+        }
+        return buffer;
+    }
+
+    /**
+     * Return true the object resources have been released.<br>
+     * @return true the object resources have been released
+     */
+    public boolean isReleased() {
+        return (0 == mNativeId);
+    }
+
+    /**
+     * Build a string-string dictionary from a jsonObject.<br>
+     * @param jsonObject the object to parse
+     * @return the map
+     */
+    public static Map<String, String> toStringMap(JSONObject jsonObject) {
+        if (null != jsonObject) {
+            HashMap<String, String> map = new HashMap<>();
+            Iterator<String> keysItr = jsonObject.keys();
+            while(keysItr.hasNext()) {
+                String key = keysItr.next();
+                try {
+                    Object value = jsonObject.get(key);
+
+                    if (value instanceof String) {
+                        map.put(key, (String) value);
+                    } else {
+                        Log.e(LOG_TAG, "## toStringMap(): unexpected type " + value.getClass());
+                    }
+                } catch (Exception e) {
+                    Log.e(LOG_TAG, "## toStringMap(): failed " + e.getMessage());
+                }
+            }
+
+            return map;
+        }
+
+        return null;
+    }
+
+    /**
+     * Build a string-string dictionary of string dictionary from a jsonObject.<br>
+     * @param jsonObject the object to parse
+     * @return the map
+     */
+    public static Map<String, Map<String, String>> toStringMapMap(JSONObject jsonObject) {
+        if (null != jsonObject) {
+            HashMap<String, Map<String, String>> map = new HashMap<>();
+
+            Iterator<String> keysItr = jsonObject.keys();
+            while(keysItr.hasNext()) {
+                String key = keysItr.next();
+                try {
+                    Object value = jsonObject.get(key);
+
+                    if (value instanceof JSONObject) {
+                        map.put(key, toStringMap((JSONObject) value));
+                    } else {
+                        Log.e(LOG_TAG, "## toStringMapMap(): unexpected type " + value.getClass());
+                    }
+                } catch (Exception e) {
+                    Log.e(LOG_TAG, "## toStringMapMap(): failed " + e.getMessage());
+                }
+            }
+
+            return map;
+        }
+
+        return null;
+    }
+}
+