8 files changed, 1239 insertions, 42 deletions

diff --git a/src/java/org/bitcoin/NativeSecp256k1.java b/src/java/org/bitcoin/NativeSecp256k1.java
index 90a498eaa2..1c67802fba 100644
--- a/src/java/org/bitcoin/NativeSecp256k1.java
+++ b/src/java/org/bitcoin/NativeSecp256k1.java
@@ -1,60 +1,446 @@
+/*
+ * Copyright 2013 Google Inc.
+ * Copyright 2014-2016 the libsecp256k1 contributors
+ *
+ * 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.bitcoin;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 
+import java.math.BigInteger;
 import com.google.common.base.Preconditions;
-
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import static org.bitcoin.NativeSecp256k1Util.*;
 
 /**
- * This class holds native methods to handle ECDSA verification.
- * You can find an example library that can be used for this at
- * https://github.com/sipa/secp256k1
+ * <p>This class holds native methods to handle ECDSA verification.</p>
+ *
+ * <p>You can find an example library that can be used for this at https://github.com/bitcoin/secp256k1</p>
+ *
+ * <p>To build secp256k1 for use with bitcoinj, run
+ * `./configure --enable-jni --enable-experimental --enable-module-ecdh`
+ * and `make` then copy `.libs/libsecp256k1.so` to your system library path
+ * or point the JVM to the folder containing it with -Djava.library.path
+ * </p>
  */
 public class NativeSecp256k1 {
-    public static final boolean enabled;
-    static {
-        boolean isEnabled = true;
-        try {
-            System.loadLibrary("javasecp256k1");
-        } catch (UnsatisfiedLinkError e) {
-            isEnabled = false;
-        }
-        enabled = isEnabled;
-    }
-    
+
+    private static final ReentrantReadWriteLock rwl = new ReentrantReadWriteLock();
+    private static final Lock r = rwl.readLock();
+    private static final Lock w = rwl.writeLock();
     private static ThreadLocal<ByteBuffer> nativeECDSABuffer = new ThreadLocal<ByteBuffer>();
     /**
      * Verifies the given secp256k1 signature in native code.
      * Calling when enabled == false is undefined (probably library not loaded)
-     * 
+     *
      * @param data The data which was signed, must be exactly 32 bytes
      * @param signature The signature
      * @param pub The public key which did the signing
      */
-    public static boolean verify(byte[] data, byte[] signature, byte[] pub) {
+    public static boolean verify(byte[] data, byte[] signature, byte[] pub) throws AssertFailException{
         Preconditions.checkArgument(data.length == 32 && signature.length <= 520 && pub.length <= 520);
 
         ByteBuffer byteBuff = nativeECDSABuffer.get();
-        if (byteBuff == null) {
-            byteBuff = ByteBuffer.allocateDirect(32 + 8 + 520 + 520);
+        if (byteBuff == null || byteBuff.capacity() < 520) {
+            byteBuff = ByteBuffer.allocateDirect(520);
             byteBuff.order(ByteOrder.nativeOrder());
             nativeECDSABuffer.set(byteBuff);
         }
         byteBuff.rewind();
         byteBuff.put(data);
-        byteBuff.putInt(signature.length);
-        byteBuff.putInt(pub.length);
         byteBuff.put(signature);
         byteBuff.put(pub);
-        return secp256k1_ecdsa_verify(byteBuff) == 1;
+
+        byte[][] retByteArray;
+
+        r.lock();
+        try {
+          return secp256k1_ecdsa_verify(byteBuff, Secp256k1Context.getContext(), signature.length, pub.length) == 1;
+        } finally {
+          r.unlock();
+        }
+    }
+
+    /**
+     * libsecp256k1 Create an ECDSA signature.
+     *
+     * @param data Message hash, 32 bytes
+     * @param key Secret key, 32 bytes
+     *
+     * Return values
+     * @param sig byte array of signature
+     */
+    public static byte[] sign(byte[] data, byte[] sec) throws AssertFailException{
+        Preconditions.checkArgument(data.length == 32 && sec.length <= 32);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < 32 + 32) {
+            byteBuff = ByteBuffer.allocateDirect(32 + 32);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(data);
+        byteBuff.put(sec);
+
+        byte[][] retByteArray;
+
+        r.lock();
+        try {
+          retByteArray = secp256k1_ecdsa_sign(byteBuff, Secp256k1Context.getContext());
+        } finally {
+          r.unlock();
+        }
+
+        byte[] sigArr = retByteArray[0];
+        int sigLen = new BigInteger(new byte[] { retByteArray[1][0] }).intValue();
+        int retVal = new BigInteger(new byte[] { retByteArray[1][1] }).intValue();
+
+        assertEquals(sigArr.length, sigLen, "Got bad signature length.");
+
+        return retVal == 0 ? new byte[0] : sigArr;
+    }
+
+    /**
+     * libsecp256k1 Seckey Verify - returns 1 if valid, 0 if invalid
+     *
+     * @param seckey ECDSA Secret key, 32 bytes
+     */
+    public static boolean secKeyVerify(byte[] seckey) {
+        Preconditions.checkArgument(seckey.length == 32);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < seckey.length) {
+            byteBuff = ByteBuffer.allocateDirect(seckey.length);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(seckey);
+
+        r.lock();
+        try {
+          return secp256k1_ec_seckey_verify(byteBuff,Secp256k1Context.getContext()) == 1;
+        } finally {
+          r.unlock();
+        }
+    }
+
+
+    /**
+     * libsecp256k1 Compute Pubkey - computes public key from secret key
+     *
+     * @param seckey ECDSA Secret key, 32 bytes
+     *
+     * Return values
+     * @param pubkey ECDSA Public key, 33 or 65 bytes
+     */
+    //TODO add a 'compressed' arg
+    public static byte[] computePubkey(byte[] seckey) throws AssertFailException{
+        Preconditions.checkArgument(seckey.length == 32);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < seckey.length) {
+            byteBuff = ByteBuffer.allocateDirect(seckey.length);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(seckey);
+
+        byte[][] retByteArray;
+
+        r.lock();
+        try {
+          retByteArray = secp256k1_ec_pubkey_create(byteBuff, Secp256k1Context.getContext());
+        } finally {
+          r.unlock();
+        }
+
+        byte[] pubArr = retByteArray[0];
+        int pubLen = new BigInteger(new byte[] { retByteArray[1][0] }).intValue();
+        int retVal = new BigInteger(new byte[] { retByteArray[1][1] }).intValue();
+
+        assertEquals(pubArr.length, pubLen, "Got bad pubkey length.");
+
+        return retVal == 0 ? new byte[0]: pubArr;
+    }
+
+    /**
+     * libsecp256k1 Cleanup - This destroys the secp256k1 context object
+     * This should be called at the end of the program for proper cleanup of the context.
+     */
+    public static synchronized void cleanup() {
+        w.lock();
+        try {
+          secp256k1_destroy_context(Secp256k1Context.getContext());
+        } finally {
+          w.unlock();
+        }
+    }
+
+    public static long cloneContext() {
+       r.lock();
+       try {
+        return secp256k1_ctx_clone(Secp256k1Context.getContext());
+       } finally { r.unlock(); }
+    }
+
+    /**
+     * libsecp256k1 PrivKey Tweak-Mul - Tweak privkey by multiplying to it
+     *
+     * @param tweak some bytes to tweak with
+     * @param seckey 32-byte seckey
+     */
+    public static byte[] privKeyTweakMul(byte[] privkey, byte[] tweak) throws AssertFailException{
+        Preconditions.checkArgument(privkey.length == 32);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < privkey.length + tweak.length) {
+            byteBuff = ByteBuffer.allocateDirect(privkey.length + tweak.length);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(privkey);
+        byteBuff.put(tweak);
+
+        byte[][] retByteArray;
+        r.lock();
+        try {
+          retByteArray = secp256k1_privkey_tweak_mul(byteBuff,Secp256k1Context.getContext());
+        } finally {
+          r.unlock();
+        }
+
+        byte[] privArr = retByteArray[0];
+
+        int privLen = (byte) new BigInteger(new byte[] { retByteArray[1][0] }).intValue() & 0xFF;
+        int retVal = new BigInteger(new byte[] { retByteArray[1][1] }).intValue();
+
+        assertEquals(privArr.length, privLen, "Got bad pubkey length.");
+
+        assertEquals(retVal, 1, "Failed return value check.");
+
+        return privArr;
+    }
+
+    /**
+     * libsecp256k1 PrivKey Tweak-Add - Tweak privkey by adding to it
+     *
+     * @param tweak some bytes to tweak with
+     * @param seckey 32-byte seckey
+     */
+    public static byte[] privKeyTweakAdd(byte[] privkey, byte[] tweak) throws AssertFailException{
+        Preconditions.checkArgument(privkey.length == 32);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < privkey.length + tweak.length) {
+            byteBuff = ByteBuffer.allocateDirect(privkey.length + tweak.length);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(privkey);
+        byteBuff.put(tweak);
+
+        byte[][] retByteArray;
+        r.lock();
+        try {
+          retByteArray = secp256k1_privkey_tweak_add(byteBuff,Secp256k1Context.getContext());
+        } finally {
+          r.unlock();
+        }
+
+        byte[] privArr = retByteArray[0];
+
+        int privLen = (byte) new BigInteger(new byte[] { retByteArray[1][0] }).intValue() & 0xFF;
+        int retVal = new BigInteger(new byte[] { retByteArray[1][1] }).intValue();
+
+        assertEquals(privArr.length, privLen, "Got bad pubkey length.");
+
+        assertEquals(retVal, 1, "Failed return value check.");
+
+        return privArr;
+    }
+
+    /**
+     * libsecp256k1 PubKey Tweak-Add - Tweak pubkey by adding to it
+     *
+     * @param tweak some bytes to tweak with
+     * @param pubkey 32-byte seckey
+     */
+    public static byte[] pubKeyTweakAdd(byte[] pubkey, byte[] tweak) throws AssertFailException{
+        Preconditions.checkArgument(pubkey.length == 33 || pubkey.length == 65);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < pubkey.length + tweak.length) {
+            byteBuff = ByteBuffer.allocateDirect(pubkey.length + tweak.length);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(pubkey);
+        byteBuff.put(tweak);
+
+        byte[][] retByteArray;
+        r.lock();
+        try {
+          retByteArray = secp256k1_pubkey_tweak_add(byteBuff,Secp256k1Context.getContext(), pubkey.length);
+        } finally {
+          r.unlock();
+        }
+
+        byte[] pubArr = retByteArray[0];
+
+        int pubLen = (byte) new BigInteger(new byte[] { retByteArray[1][0] }).intValue() & 0xFF;
+        int retVal = new BigInteger(new byte[] { retByteArray[1][1] }).intValue();
+
+        assertEquals(pubArr.length, pubLen, "Got bad pubkey length.");
+
+        assertEquals(retVal, 1, "Failed return value check.");
+
+        return pubArr;
+    }
+
+    /**
+     * libsecp256k1 PubKey Tweak-Mul - Tweak pubkey by multiplying to it
+     *
+     * @param tweak some bytes to tweak with
+     * @param pubkey 32-byte seckey
+     */
+    public static byte[] pubKeyTweakMul(byte[] pubkey, byte[] tweak) throws AssertFailException{
+        Preconditions.checkArgument(pubkey.length == 33 || pubkey.length == 65);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < pubkey.length + tweak.length) {
+            byteBuff = ByteBuffer.allocateDirect(pubkey.length + tweak.length);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(pubkey);
+        byteBuff.put(tweak);
+
+        byte[][] retByteArray;
+        r.lock();
+        try {
+          retByteArray = secp256k1_pubkey_tweak_mul(byteBuff,Secp256k1Context.getContext(), pubkey.length);
+        } finally {
+          r.unlock();
+        }
+
+        byte[] pubArr = retByteArray[0];
+
+        int pubLen = (byte) new BigInteger(new byte[] { retByteArray[1][0] }).intValue() & 0xFF;
+        int retVal = new BigInteger(new byte[] { retByteArray[1][1] }).intValue();
+
+        assertEquals(pubArr.length, pubLen, "Got bad pubkey length.");
+
+        assertEquals(retVal, 1, "Failed return value check.");
+
+        return pubArr;
     }
 
     /**
-     * @param byteBuff signature format is byte[32] data,
-     *        native-endian int signatureLength, native-endian int pubkeyLength,
-     *        byte[signatureLength] signature, byte[pubkeyLength] pub
-     * @returns 1 for valid signature, anything else for invalid
+     * libsecp256k1 create ECDH secret - constant time ECDH calculation
+     *
+     * @param seckey byte array of secret key used in exponentiaion
+     * @param pubkey byte array of public key used in exponentiaion
      */
-    private static native int secp256k1_ecdsa_verify(ByteBuffer byteBuff);
+    public static byte[] createECDHSecret(byte[] seckey, byte[] pubkey) throws AssertFailException{
+        Preconditions.checkArgument(seckey.length <= 32 && pubkey.length <= 65);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < 32 + pubkey.length) {
+            byteBuff = ByteBuffer.allocateDirect(32 + pubkey.length);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(seckey);
+        byteBuff.put(pubkey);
+
+        byte[][] retByteArray;
+        r.lock();
+        try {
+          retByteArray = secp256k1_ecdh(byteBuff, Secp256k1Context.getContext(), pubkey.length);
+        } finally {
+          r.unlock();
+        }
+
+        byte[] resArr = retByteArray[0];
+        int retVal = new BigInteger(new byte[] { retByteArray[1][0] }).intValue();
+
+        assertEquals(resArr.length, 32, "Got bad result length.");
+        assertEquals(retVal, 1, "Failed return value check.");
+
+        return resArr;
+    }
+
+    /**
+     * libsecp256k1 randomize - updates the context randomization
+     *
+     * @param seed 32-byte random seed
+     */
+    public static synchronized boolean randomize(byte[] seed) throws AssertFailException{
+        Preconditions.checkArgument(seed.length == 32 || seed == null);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < seed.length) {
+            byteBuff = ByteBuffer.allocateDirect(seed.length);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(seed);
+
+        w.lock();
+        try {
+          return secp256k1_context_randomize(byteBuff, Secp256k1Context.getContext()) == 1;
+        } finally {
+          w.unlock();
+        }
+    }
+
+    private static native long secp256k1_ctx_clone(long context);
+
+    private static native int secp256k1_context_randomize(ByteBuffer byteBuff, long context);
+
+    private static native byte[][] secp256k1_privkey_tweak_add(ByteBuffer byteBuff, long context);
+
+    private static native byte[][] secp256k1_privkey_tweak_mul(ByteBuffer byteBuff, long context);
+
+    private static native byte[][] secp256k1_pubkey_tweak_add(ByteBuffer byteBuff, long context, int pubLen);
+
+    private static native byte[][] secp256k1_pubkey_tweak_mul(ByteBuffer byteBuff, long context, int pubLen);
+
+    private static native void secp256k1_destroy_context(long context);
+
+    private static native int secp256k1_ecdsa_verify(ByteBuffer byteBuff, long context, int sigLen, int pubLen);
+
+    private static native byte[][] secp256k1_ecdsa_sign(ByteBuffer byteBuff, long context);
+
+    private static native int secp256k1_ec_seckey_verify(ByteBuffer byteBuff, long context);
+
+    private static native byte[][] secp256k1_ec_pubkey_create(ByteBuffer byteBuff, long context);
+
+    private static native byte[][] secp256k1_ec_pubkey_parse(ByteBuffer byteBuff, long context, int inputLen);
+
+    private static native byte[][] secp256k1_ecdh(ByteBuffer byteBuff, long context, int inputLen);
+
 }
diff --git a/src/java/org/bitcoin/NativeSecp256k1Test.java b/src/java/org/bitcoin/NativeSecp256k1Test.java
new file mode 100644
index 0000000000..c00d08899b
--- /dev/null
+++ b/src/java/org/bitcoin/NativeSecp256k1Test.java
@@ -0,0 +1,226 @@
+package org.bitcoin;
+
+import com.google.common.io.BaseEncoding;
+import java.util.Arrays;
+import java.math.BigInteger;
+import javax.xml.bind.DatatypeConverter;
+import static org.bitcoin.NativeSecp256k1Util.*;
+
+/**
+ * This class holds test cases defined for testing this library.
+ */
+public class NativeSecp256k1Test {
+
+    //TODO improve comments/add more tests
+    /**
+      * This tests verify() for a valid signature
+      */
+    public static void testVerifyPos() throws AssertFailException{
+        boolean result = false;
+        byte[] data = BaseEncoding.base16().lowerCase().decode("CF80CD8AED482D5D1527D7DC72FCEFF84E6326592848447D2DC0B0E87DFC9A90".toLowerCase()); //sha256hash of "testing"
+        byte[] sig = BaseEncoding.base16().lowerCase().decode("3044022079BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F817980220294F14E883B3F525B5367756C2A11EF6CF84B730B36C17CB0C56F0AAB2C98589".toLowerCase());
+        byte[] pub = BaseEncoding.base16().lowerCase().decode("040A629506E1B65CD9D2E0BA9C75DF9C4FED0DB16DC9625ED14397F0AFC836FAE595DC53F8B0EFE61E703075BD9B143BAC75EC0E19F82A2208CAEB32BE53414C40".toLowerCase());
+
+        result = NativeSecp256k1.verify( data, sig, pub);
+        assertEquals( result, true , "testVerifyPos");
+    }
+
+    /**
+      * This tests verify() for a non-valid signature
+      */
+    public static void testVerifyNeg() throws AssertFailException{
+        boolean result = false;
+        byte[] data = BaseEncoding.base16().lowerCase().decode("CF80CD8AED482D5D1527D7DC72FCEFF84E6326592848447D2DC0B0E87DFC9A91".toLowerCase()); //sha256hash of "testing"
+        byte[] sig = BaseEncoding.base16().lowerCase().decode("3044022079BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F817980220294F14E883B3F525B5367756C2A11EF6CF84B730B36C17CB0C56F0AAB2C98589".toLowerCase());
+        byte[] pub = BaseEncoding.base16().lowerCase().decode("040A629506E1B65CD9D2E0BA9C75DF9C4FED0DB16DC9625ED14397F0AFC836FAE595DC53F8B0EFE61E703075BD9B143BAC75EC0E19F82A2208CAEB32BE53414C40".toLowerCase());
+
+        result = NativeSecp256k1.verify( data, sig, pub);
+        //System.out.println(" TEST " + new BigInteger(1, resultbytes).toString(16));
+        assertEquals( result, false , "testVerifyNeg");
+    }
+
+    /**
+      * This tests secret key verify() for a valid secretkey
+      */
+    public static void testSecKeyVerifyPos() throws AssertFailException{
+        boolean result = false;
+        byte[] sec = BaseEncoding.base16().lowerCase().decode("67E56582298859DDAE725F972992A07C6C4FB9F62A8FFF58CE3CA926A1063530".toLowerCase());
+
+        result = NativeSecp256k1.secKeyVerify( sec );
+        //System.out.println(" TEST " + new BigInteger(1, resultbytes).toString(16));
+        assertEquals( result, true , "testSecKeyVerifyPos");
+    }
+
+    /**
+      * This tests secret key verify() for a invalid secretkey
+      */
+    public static void testSecKeyVerifyNeg() throws AssertFailException{
+        boolean result = false;
+        byte[] sec = BaseEncoding.base16().lowerCase().decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF".toLowerCase());
+
+        result = NativeSecp256k1.secKeyVerify( sec );
+        //System.out.println(" TEST " + new BigInteger(1, resultbytes).toString(16));
+        assertEquals( result, false , "testSecKeyVerifyNeg");
+    }
+
+    /**
+      * This tests public key create() for a valid secretkey
+      */
+    public static void testPubKeyCreatePos() throws AssertFailException{
+        byte[] sec = BaseEncoding.base16().lowerCase().decode("67E56582298859DDAE725F972992A07C6C4FB9F62A8FFF58CE3CA926A1063530".toLowerCase());
+
+        byte[] resultArr = NativeSecp256k1.computePubkey( sec);
+        String pubkeyString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+        assertEquals( pubkeyString , "04C591A8FF19AC9C4E4E5793673B83123437E975285E7B442F4EE2654DFFCA5E2D2103ED494718C697AC9AEBCFD19612E224DB46661011863ED2FC54E71861E2A6" , "testPubKeyCreatePos");
+    }
+
+    /**
+      * This tests public key create() for a invalid secretkey
+      */
+    public static void testPubKeyCreateNeg() throws AssertFailException{
+       byte[] sec = BaseEncoding.base16().lowerCase().decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF".toLowerCase());
+
+       byte[] resultArr = NativeSecp256k1.computePubkey( sec);
+       String pubkeyString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+       assertEquals( pubkeyString, "" , "testPubKeyCreateNeg");
+    }
+
+    /**
+      * This tests sign() for a valid secretkey
+      */
+    public static void testSignPos() throws AssertFailException{
+
+        byte[] data = BaseEncoding.base16().lowerCase().decode("CF80CD8AED482D5D1527D7DC72FCEFF84E6326592848447D2DC0B0E87DFC9A90".toLowerCase()); //sha256hash of "testing"
+        byte[] sec = BaseEncoding.base16().lowerCase().decode("67E56582298859DDAE725F972992A07C6C4FB9F62A8FFF58CE3CA926A1063530".toLowerCase());
+
+        byte[] resultArr = NativeSecp256k1.sign(data, sec);
+        String sigString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+        assertEquals( sigString, "30440220182A108E1448DC8F1FB467D06A0F3BB8EA0533584CB954EF8DA112F1D60E39A202201C66F36DA211C087F3AF88B50EDF4F9BDAA6CF5FD6817E74DCA34DB12390C6E9" , "testSignPos");
+    }
+
+    /**
+      * This tests sign() for a invalid secretkey
+      */
+    public static void testSignNeg() throws AssertFailException{
+        byte[] data = BaseEncoding.base16().lowerCase().decode("CF80CD8AED482D5D1527D7DC72FCEFF84E6326592848447D2DC0B0E87DFC9A90".toLowerCase()); //sha256hash of "testing"
+        byte[] sec = BaseEncoding.base16().lowerCase().decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF".toLowerCase());
+
+        byte[] resultArr = NativeSecp256k1.sign(data, sec);
+        String sigString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+        assertEquals( sigString, "" , "testSignNeg");
+    }
+
+    /**
+      * This tests private key tweak-add
+      */
+    public static void testPrivKeyTweakAdd_1() throws AssertFailException {
+        byte[] sec = BaseEncoding.base16().lowerCase().decode("67E56582298859DDAE725F972992A07C6C4FB9F62A8FFF58CE3CA926A1063530".toLowerCase());
+        byte[] data = BaseEncoding.base16().lowerCase().decode("3982F19BEF1615BCCFBB05E321C10E1D4CBA3DF0E841C2E41EEB6016347653C3".toLowerCase()); //sha256hash of "tweak"
+
+        byte[] resultArr = NativeSecp256k1.privKeyTweakAdd( sec , data );
+        String sigString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+        assertEquals( sigString , "A168571E189E6F9A7E2D657A4B53AE99B909F7E712D1C23CED28093CD57C88F3" , "testPrivKeyAdd_1");
+    }
+
+    /**
+      * This tests private key tweak-mul
+      */
+    public static void testPrivKeyTweakMul_1() throws AssertFailException {
+        byte[] sec = BaseEncoding.base16().lowerCase().decode("67E56582298859DDAE725F972992A07C6C4FB9F62A8FFF58CE3CA926A1063530".toLowerCase());
+        byte[] data = BaseEncoding.base16().lowerCase().decode("3982F19BEF1615BCCFBB05E321C10E1D4CBA3DF0E841C2E41EEB6016347653C3".toLowerCase()); //sha256hash of "tweak"
+
+        byte[] resultArr = NativeSecp256k1.privKeyTweakMul( sec , data );
+        String sigString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+        assertEquals( sigString , "97F8184235F101550F3C71C927507651BD3F1CDB4A5A33B8986ACF0DEE20FFFC" , "testPrivKeyMul_1");
+    }
+
+    /**
+      * This tests private key tweak-add uncompressed
+      */
+    public static void testPrivKeyTweakAdd_2() throws AssertFailException {
+        byte[] pub = BaseEncoding.base16().lowerCase().decode("040A629506E1B65CD9D2E0BA9C75DF9C4FED0DB16DC9625ED14397F0AFC836FAE595DC53F8B0EFE61E703075BD9B143BAC75EC0E19F82A2208CAEB32BE53414C40".toLowerCase());
+        byte[] data = BaseEncoding.base16().lowerCase().decode("3982F19BEF1615BCCFBB05E321C10E1D4CBA3DF0E841C2E41EEB6016347653C3".toLowerCase()); //sha256hash of "tweak"
+
+        byte[] resultArr = NativeSecp256k1.pubKeyTweakAdd( pub , data );
+        String sigString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+        assertEquals( sigString , "0411C6790F4B663CCE607BAAE08C43557EDC1A4D11D88DFCB3D841D0C6A941AF525A268E2A863C148555C48FB5FBA368E88718A46E205FABC3DBA2CCFFAB0796EF" , "testPrivKeyAdd_2");
+    }
+
+    /**
+      * This tests private key tweak-mul uncompressed
+      */
+    public static void testPrivKeyTweakMul_2() throws AssertFailException {
+        byte[] pub = BaseEncoding.base16().lowerCase().decode("040A629506E1B65CD9D2E0BA9C75DF9C4FED0DB16DC9625ED14397F0AFC836FAE595DC53F8B0EFE61E703075BD9B143BAC75EC0E19F82A2208CAEB32BE53414C40".toLowerCase());
+        byte[] data = BaseEncoding.base16().lowerCase().decode("3982F19BEF1615BCCFBB05E321C10E1D4CBA3DF0E841C2E41EEB6016347653C3".toLowerCase()); //sha256hash of "tweak"
+
+        byte[] resultArr = NativeSecp256k1.pubKeyTweakMul( pub , data );
+        String sigString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+        assertEquals( sigString , "04E0FE6FE55EBCA626B98A807F6CAF654139E14E5E3698F01A9A658E21DC1D2791EC060D4F412A794D5370F672BC94B722640B5F76914151CFCA6E712CA48CC589" , "testPrivKeyMul_2");
+    }
+
+    /**
+      * This tests seed randomization
+      */
+    public static void testRandomize() throws AssertFailException {
+        byte[] seed = BaseEncoding.base16().lowerCase().decode("A441B15FE9A3CF56661190A0B93B9DEC7D04127288CC87250967CF3B52894D11".toLowerCase()); //sha256hash of "random"
+        boolean result = NativeSecp256k1.randomize(seed);
+        assertEquals( result, true, "testRandomize");
+    }
+
+    public static void testCreateECDHSecret() throws AssertFailException{
+
+        byte[] sec = BaseEncoding.base16().lowerCase().decode("67E56582298859DDAE725F972992A07C6C4FB9F62A8FFF58CE3CA926A1063530".toLowerCase());
+        byte[] pub = BaseEncoding.base16().lowerCase().decode("040A629506E1B65CD9D2E0BA9C75DF9C4FED0DB16DC9625ED14397F0AFC836FAE595DC53F8B0EFE61E703075BD9B143BAC75EC0E19F82A2208CAEB32BE53414C40".toLowerCase());
+
+        byte[] resultArr = NativeSecp256k1.createECDHSecret(sec, pub);
+        String ecdhString = javax.xml.bind.DatatypeConverter.printHexBinary(resultArr);
+        assertEquals( ecdhString, "2A2A67007A926E6594AF3EB564FC74005B37A9C8AEF2033C4552051B5C87F043" , "testCreateECDHSecret");
+    }
+
+    public static void main(String[] args) throws AssertFailException{
+
+
+        System.out.println("\n libsecp256k1 enabled: " + Secp256k1Context.isEnabled() + "\n");
+
+        assertEquals( Secp256k1Context.isEnabled(), true, "isEnabled" );
+
+        //Test verify() success/fail
+        testVerifyPos();
+        testVerifyNeg();
+
+        //Test secKeyVerify() success/fail
+        testSecKeyVerifyPos();
+        testSecKeyVerifyNeg();
+
+        //Test computePubkey() success/fail
+        testPubKeyCreatePos();
+        testPubKeyCreateNeg();
+
+        //Test sign() success/fail
+        testSignPos();
+        testSignNeg();
+
+        //Test privKeyTweakAdd() 1
+        testPrivKeyTweakAdd_1();
+
+        //Test privKeyTweakMul() 2
+        testPrivKeyTweakMul_1();
+
+        //Test privKeyTweakAdd() 3
+        testPrivKeyTweakAdd_2();
+
+        //Test privKeyTweakMul() 4
+        testPrivKeyTweakMul_2();
+
+        //Test randomize()
+        testRandomize();
+
+        //Test ECDH
+        testCreateECDHSecret();
+
+        NativeSecp256k1.cleanup();
+
+        System.out.println(" All tests passed." );
+
+    }
+}
diff --git a/src/java/org/bitcoin/NativeSecp256k1Util.java b/src/java/org/bitcoin/NativeSecp256k1Util.java
new file mode 100644
index 0000000000..04732ba044
--- /dev/null
+++ b/src/java/org/bitcoin/NativeSecp256k1Util.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2014-2016 the libsecp256k1 contributors
+ *
+ * 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.bitcoin;
+
+public class NativeSecp256k1Util{
+
+    public static void assertEquals( int val, int val2, String message ) throws AssertFailException{
+      if( val != val2 )
+        throw new AssertFailException("FAIL: " + message);
+    }
+
+    public static void assertEquals( boolean val, boolean val2, String message ) throws AssertFailException{
+      if( val != val2 )
+        throw new AssertFailException("FAIL: " + message);
+      else
+        System.out.println("PASS: " + message);
+    }
+
+    public static void assertEquals( String val, String val2, String message ) throws AssertFailException{
+      if( !val.equals(val2) )
+        throw new AssertFailException("FAIL: " + message);
+      else
+        System.out.println("PASS: " + message);
+    }
+
+    public static class AssertFailException extends Exception {
+      public AssertFailException(String message) {
+        super( message );
+      }
+    }
+}
diff --git a/src/java/org/bitcoin/Secp256k1Context.java b/src/java/org/bitcoin/Secp256k1Context.java
new file mode 100644
index 0000000000..216c986a8b
--- /dev/null
+++ b/src/java/org/bitcoin/Secp256k1Context.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2014-2016 the libsecp256k1 contributors
+ *
+ * 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.bitcoin;
+
+/**
+ * This class holds the context reference used in native methods 
+ * to handle ECDSA operations.
+ */
+public class Secp256k1Context {
+  private static final boolean enabled; //true if the library is loaded
+  private static final long context; //ref to pointer to context obj
+
+  static { //static initializer
+      boolean isEnabled = true;
+      long contextRef = -1;
+      try {
+          System.loadLibrary("secp256k1");
+          contextRef = secp256k1_init_context();
+      } catch (UnsatisfiedLinkError e) {
+          System.out.println("UnsatisfiedLinkError: " + e.toString());
+          isEnabled = false;
+      }
+      enabled = isEnabled;
+      context = contextRef;
+  }
+
+  public static boolean isEnabled() {
+     return enabled;
+  }
+
+  public static long getContext() {
+     if(!enabled) return -1; //sanity check
+     return context;
+  }
+
+  private static native long secp256k1_init_context();
+}
diff --git a/src/java/org_bitcoin_NativeSecp256k1.c b/src/java/org_bitcoin_NativeSecp256k1.c
index bb4cd70728..bcef7b32ce 100644
--- a/src/java/org_bitcoin_NativeSecp256k1.c
+++ b/src/java/org_bitcoin_NativeSecp256k1.c
@@ -1,23 +1,377 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
 #include "org_bitcoin_NativeSecp256k1.h"
 #include "include/secp256k1.h"
+#include "include/secp256k1_ecdh.h"
+#include "include/secp256k1_recovery.h"
 
-JNIEXPORT jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1verify
-  (JNIEnv* env, jclass classObject, jobject byteBufferObject)
+
+SECP256K1_API jlong JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ctx_1clone
+  (JNIEnv* env, jclass classObject, jlong ctx_l)
+{
+  const secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+
+  jlong ctx_clone_l = (uintptr_t) secp256k1_context_clone(ctx);
+
+  (void)classObject;(void)env;
+
+  return ctx_clone_l;
+
+}
+
+SECP256K1_API jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1context_1randomize
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l)
 {
-	unsigned char* data = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
-	int sigLen = *((int*)(data + 32));
-	int pubLen = *((int*)(data + 32 + 4));
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+
+  const unsigned char* seed = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
+
+  (void)classObject;
+
+  return secp256k1_context_randomize(ctx, seed);
 
-	return secp256k1_ecdsa_verify(data, 32, data+32+8, sigLen, data+32+8+sigLen, pubLen);
 }
 
-static void __javasecp256k1_attach(void) __attribute__((constructor));
-static void __javasecp256k1_detach(void) __attribute__((destructor));
+SECP256K1_API void JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1destroy_1context
+  (JNIEnv* env, jclass classObject, jlong ctx_l)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+
+  secp256k1_context_destroy(ctx);
 
-static void __javasecp256k1_attach(void) {
-	secp256k1_start(SECP256K1_START_VERIFY);
+  (void)classObject;(void)env;
 }
 
-static void __javasecp256k1_detach(void) {
-	secp256k1_stop();
+SECP256K1_API jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1verify
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l, jint siglen, jint publen)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+
+  unsigned char* data = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
+  const unsigned char* sigdata = {  (unsigned char*) (data + 32) };
+  const unsigned char* pubdata = { (unsigned char*) (data + siglen + 32) };
+
+  secp256k1_ecdsa_signature sig;
+  secp256k1_pubkey pubkey;
+
+  int ret = secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigdata, siglen);
+
+  if( ret ) {
+    ret = secp256k1_ec_pubkey_parse(ctx, &pubkey, pubdata, publen);
+
+    if( ret ) {
+      ret = secp256k1_ecdsa_verify(ctx, &sig, data, &pubkey);
+    }
+  }
+
+  (void)classObject;
+
+  return ret;
+}
+
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1sign
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+  unsigned char* data = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
+  unsigned char* secKey = (unsigned char*) (data + 32);
+
+  jobjectArray retArray;
+  jbyteArray sigArray, intsByteArray;
+  unsigned char intsarray[2];
+
+  secp256k1_ecdsa_signature sig[72];
+
+  int ret = secp256k1_ecdsa_sign(ctx, sig, data, secKey, NULL, NULL );
+
+  unsigned char outputSer[72];
+  size_t outputLen = 72;
+
+  if( ret ) {
+    int ret2 = secp256k1_ecdsa_signature_serialize_der(ctx,outputSer, &outputLen, sig ); (void)ret2;
+  }
+
+  intsarray[0] = outputLen;
+  intsarray[1] = ret;
+
+  retArray = (*env)->NewObjectArray(env, 2,
+    (*env)->FindClass(env, "[B"),
+    (*env)->NewByteArray(env, 1));
+
+  sigArray = (*env)->NewByteArray(env, outputLen);
+  (*env)->SetByteArrayRegion(env, sigArray, 0, outputLen, (jbyte*)outputSer);
+  (*env)->SetObjectArrayElement(env, retArray, 0, sigArray);
+
+  intsByteArray = (*env)->NewByteArray(env, 2);
+  (*env)->SetByteArrayRegion(env, intsByteArray, 0, 2, (jbyte*)intsarray);
+  (*env)->SetObjectArrayElement(env, retArray, 1, intsByteArray);
+
+  (void)classObject;
+
+  return retArray;
+}
+
+SECP256K1_API jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ec_1seckey_1verify
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+  unsigned char* secKey = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
+
+  (void)classObject;
+
+  return secp256k1_ec_seckey_verify(ctx, secKey);
+}
+
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ec_1pubkey_1create
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+  const unsigned char* secKey = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
+
+  secp256k1_pubkey pubkey;
+
+  jobjectArray retArray;
+  jbyteArray pubkeyArray, intsByteArray;
+  unsigned char intsarray[2];
+
+  int ret = secp256k1_ec_pubkey_create(ctx, &pubkey, secKey);
+
+  unsigned char outputSer[65];
+  size_t outputLen = 65;
+
+  if( ret ) {
+    int ret2 = secp256k1_ec_pubkey_serialize(ctx,outputSer, &outputLen, &pubkey,SECP256K1_EC_UNCOMPRESSED );(void)ret2;
+  }
+
+  intsarray[0] = outputLen;
+  intsarray[1] = ret;
+
+  retArray = (*env)->NewObjectArray(env, 2,
+    (*env)->FindClass(env, "[B"),
+    (*env)->NewByteArray(env, 1));
+
+  pubkeyArray = (*env)->NewByteArray(env, outputLen);
+  (*env)->SetByteArrayRegion(env, pubkeyArray, 0, outputLen, (jbyte*)outputSer);
+  (*env)->SetObjectArrayElement(env, retArray, 0, pubkeyArray);
+
+  intsByteArray = (*env)->NewByteArray(env, 2);
+  (*env)->SetByteArrayRegion(env, intsByteArray, 0, 2, (jbyte*)intsarray);
+  (*env)->SetObjectArrayElement(env, retArray, 1, intsByteArray);
+
+  (void)classObject;
+
+  return retArray;
+
+}
+
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1privkey_1tweak_1add
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+  unsigned char* privkey = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
+  const unsigned char* tweak = (unsigned char*) (privkey + 32);
+
+  jobjectArray retArray;
+  jbyteArray privArray, intsByteArray;
+  unsigned char intsarray[2];
+
+  int privkeylen = 32;
+
+  int ret = secp256k1_ec_privkey_tweak_add(ctx, privkey, tweak);
+
+  intsarray[0] = privkeylen;
+  intsarray[1] = ret;
+
+  retArray = (*env)->NewObjectArray(env, 2,
+    (*env)->FindClass(env, "[B"),
+    (*env)->NewByteArray(env, 1));
+
+  privArray = (*env)->NewByteArray(env, privkeylen);
+  (*env)->SetByteArrayRegion(env, privArray, 0, privkeylen, (jbyte*)privkey);
+  (*env)->SetObjectArrayElement(env, retArray, 0, privArray);
+
+  intsByteArray = (*env)->NewByteArray(env, 2);
+  (*env)->SetByteArrayRegion(env, intsByteArray, 0, 2, (jbyte*)intsarray);
+  (*env)->SetObjectArrayElement(env, retArray, 1, intsByteArray);
+
+  (void)classObject;
+
+  return retArray;
+}
+
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1privkey_1tweak_1mul
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+  unsigned char* privkey = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
+  const unsigned char* tweak = (unsigned char*) (privkey + 32);
+
+  jobjectArray retArray;
+  jbyteArray privArray, intsByteArray;
+  unsigned char intsarray[2];
+
+  int privkeylen = 32;
+
+  int ret = secp256k1_ec_privkey_tweak_mul(ctx, privkey, tweak);
+
+  intsarray[0] = privkeylen;
+  intsarray[1] = ret;
+
+  retArray = (*env)->NewObjectArray(env, 2,
+    (*env)->FindClass(env, "[B"),
+    (*env)->NewByteArray(env, 1));
+
+  privArray = (*env)->NewByteArray(env, privkeylen);
+  (*env)->SetByteArrayRegion(env, privArray, 0, privkeylen, (jbyte*)privkey);
+  (*env)->SetObjectArrayElement(env, retArray, 0, privArray);
+
+  intsByteArray = (*env)->NewByteArray(env, 2);
+  (*env)->SetByteArrayRegion(env, intsByteArray, 0, 2, (jbyte*)intsarray);
+  (*env)->SetObjectArrayElement(env, retArray, 1, intsByteArray);
+
+  (void)classObject;
+
+  return retArray;
+}
+
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1pubkey_1tweak_1add
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l, jint publen)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+/*  secp256k1_pubkey* pubkey = (secp256k1_pubkey*) (*env)->GetDirectBufferAddress(env, byteBufferObject);*/
+  unsigned char* pkey = (*env)->GetDirectBufferAddress(env, byteBufferObject);
+  const unsigned char* tweak = (unsigned char*) (pkey + publen);
+
+  jobjectArray retArray;
+  jbyteArray pubArray, intsByteArray;
+  unsigned char intsarray[2];
+  unsigned char outputSer[65];
+  size_t outputLen = 65;
+
+  secp256k1_pubkey pubkey;
+  int ret = secp256k1_ec_pubkey_parse(ctx, &pubkey, pkey, publen);
+
+  if( ret ) {
+    ret = secp256k1_ec_pubkey_tweak_add(ctx, &pubkey, tweak);
+  }
+
+  if( ret ) {
+    int ret2 = secp256k1_ec_pubkey_serialize(ctx,outputSer, &outputLen, &pubkey,SECP256K1_EC_UNCOMPRESSED );(void)ret2;
+  }
+
+  intsarray[0] = outputLen;
+  intsarray[1] = ret;
+
+  retArray = (*env)->NewObjectArray(env, 2,
+    (*env)->FindClass(env, "[B"),
+    (*env)->NewByteArray(env, 1));
+
+  pubArray = (*env)->NewByteArray(env, outputLen);
+  (*env)->SetByteArrayRegion(env, pubArray, 0, outputLen, (jbyte*)outputSer);
+  (*env)->SetObjectArrayElement(env, retArray, 0, pubArray);
+
+  intsByteArray = (*env)->NewByteArray(env, 2);
+  (*env)->SetByteArrayRegion(env, intsByteArray, 0, 2, (jbyte*)intsarray);
+  (*env)->SetObjectArrayElement(env, retArray, 1, intsByteArray);
+
+  (void)classObject;
+
+  return retArray;
+}
+
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1pubkey_1tweak_1mul
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l, jint publen)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+  unsigned char* pkey = (*env)->GetDirectBufferAddress(env, byteBufferObject);
+  const unsigned char* tweak = (unsigned char*) (pkey + publen);
+
+  jobjectArray retArray;
+  jbyteArray pubArray, intsByteArray;
+  unsigned char intsarray[2];
+  unsigned char outputSer[65];
+  size_t outputLen = 65;
+
+  secp256k1_pubkey pubkey;
+  int ret = secp256k1_ec_pubkey_parse(ctx, &pubkey, pkey, publen);
+
+  if ( ret ) {
+    ret = secp256k1_ec_pubkey_tweak_mul(ctx, &pubkey, tweak);
+  }
+
+  if( ret ) {
+    int ret2 = secp256k1_ec_pubkey_serialize(ctx,outputSer, &outputLen, &pubkey,SECP256K1_EC_UNCOMPRESSED );(void)ret2;
+  }
+
+  intsarray[0] = outputLen;
+  intsarray[1] = ret;
+
+  retArray = (*env)->NewObjectArray(env, 2,
+    (*env)->FindClass(env, "[B"),
+    (*env)->NewByteArray(env, 1));
+
+  pubArray = (*env)->NewByteArray(env, outputLen);
+  (*env)->SetByteArrayRegion(env, pubArray, 0, outputLen, (jbyte*)outputSer);
+  (*env)->SetObjectArrayElement(env, retArray, 0, pubArray);
+
+  intsByteArray = (*env)->NewByteArray(env, 2);
+  (*env)->SetByteArrayRegion(env, intsByteArray, 0, 2, (jbyte*)intsarray);
+  (*env)->SetObjectArrayElement(env, retArray, 1, intsByteArray);
+
+  (void)classObject;
+
+  return retArray;
+}
+
+SECP256K1_API jlong JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1pubkey_1combine
+  (JNIEnv * env, jclass classObject, jobject byteBufferObject, jlong ctx_l, jint numkeys)
+{
+  (void)classObject;(void)env;(void)byteBufferObject;(void)ctx_l;(void)numkeys;
+
+  return 0;
+}
+
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdh
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l, jint publen)
+{
+  secp256k1_context *ctx = (secp256k1_context*)(uintptr_t)ctx_l;
+  const unsigned char* secdata = (*env)->GetDirectBufferAddress(env, byteBufferObject);
+  const unsigned char* pubdata = (const unsigned char*) (secdata + 32);
+
+  jobjectArray retArray;
+  jbyteArray outArray, intsByteArray;
+  unsigned char intsarray[1];
+  secp256k1_pubkey pubkey;
+  unsigned char nonce_res[32];
+  size_t outputLen = 32;
+
+  int ret = secp256k1_ec_pubkey_parse(ctx, &pubkey, pubdata, publen);
+
+  if (ret) {
+    ret = secp256k1_ecdh(
+      ctx,
+      nonce_res,
+      &pubkey,
+      secdata
+    );
+  }
+
+  intsarray[0] = ret;
+
+  retArray = (*env)->NewObjectArray(env, 2,
+    (*env)->FindClass(env, "[B"),
+    (*env)->NewByteArray(env, 1));
+
+  outArray = (*env)->NewByteArray(env, outputLen);
+  (*env)->SetByteArrayRegion(env, outArray, 0, 32, (jbyte*)nonce_res);
+  (*env)->SetObjectArrayElement(env, retArray, 0, outArray);
+
+  intsByteArray = (*env)->NewByteArray(env, 1);
+  (*env)->SetByteArrayRegion(env, intsByteArray, 0, 1, (jbyte*)intsarray);
+  (*env)->SetObjectArrayElement(env, retArray, 1, intsByteArray);
+
+  (void)classObject;
+
+  return retArray;
 }
diff --git a/src/java/org_bitcoin_NativeSecp256k1.h b/src/java/org_bitcoin_NativeSecp256k1.h
index d7fb004fa8..fe613c9e9e 100644
--- a/src/java/org_bitcoin_NativeSecp256k1.h
+++ b/src/java/org_bitcoin_NativeSecp256k1.h
@@ -1,5 +1,6 @@
 /* DO NOT EDIT THIS FILE - it is machine generated */
 #include <jni.h>
+#include "include/secp256k1.h"
 /* Header for class org_bitcoin_NativeSecp256k1 */
 
 #ifndef _Included_org_bitcoin_NativeSecp256k1
@@ -9,11 +10,108 @@ extern "C" {
 #endif
 /*
  * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_ctx_clone
+ * Signature: (J)J
+ */
+SECP256K1_API jlong JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ctx_1clone
+  (JNIEnv *, jclass, jlong);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_context_randomize
+ * Signature: (Ljava/nio/ByteBuffer;J)I
+ */
+SECP256K1_API jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1context_1randomize
+  (JNIEnv *, jclass, jobject, jlong);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_privkey_tweak_add
+ * Signature: (Ljava/nio/ByteBuffer;J)[[B
+ */
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1privkey_1tweak_1add
+  (JNIEnv *, jclass, jobject, jlong);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_privkey_tweak_mul
+ * Signature: (Ljava/nio/ByteBuffer;J)[[B
+ */
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1privkey_1tweak_1mul
+  (JNIEnv *, jclass, jobject, jlong);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_pubkey_tweak_add
+ * Signature: (Ljava/nio/ByteBuffer;JI)[[B
+ */
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1pubkey_1tweak_1add
+  (JNIEnv *, jclass, jobject, jlong, jint);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_pubkey_tweak_mul
+ * Signature: (Ljava/nio/ByteBuffer;JI)[[B
+ */
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1pubkey_1tweak_1mul
+  (JNIEnv *, jclass, jobject, jlong, jint);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_destroy_context
+ * Signature: (J)V
+ */
+SECP256K1_API void JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1destroy_1context
+  (JNIEnv *, jclass, jlong);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
  * Method:    secp256k1_ecdsa_verify
- * Signature: (Ljava/nio/ByteBuffer;)I
+ * Signature: (Ljava/nio/ByteBuffer;JII)I
+ */
+SECP256K1_API jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1verify
+  (JNIEnv *, jclass, jobject, jlong, jint, jint);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_ecdsa_sign
+ * Signature: (Ljava/nio/ByteBuffer;J)[[B
+ */
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1sign
+  (JNIEnv *, jclass, jobject, jlong);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_ec_seckey_verify
+ * Signature: (Ljava/nio/ByteBuffer;J)I
+ */
+SECP256K1_API jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ec_1seckey_1verify
+  (JNIEnv *, jclass, jobject, jlong);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_ec_pubkey_create
+ * Signature: (Ljava/nio/ByteBuffer;J)[[B
+ */
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ec_1pubkey_1create
+  (JNIEnv *, jclass, jobject, jlong);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_ec_pubkey_parse
+ * Signature: (Ljava/nio/ByteBuffer;JI)[[B
+ */
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ec_1pubkey_1parse
+  (JNIEnv *, jclass, jobject, jlong, jint);
+
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_ecdh
+ * Signature: (Ljava/nio/ByteBuffer;JI)[[B
  */
-JNIEXPORT jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1verify
-  (JNIEnv *, jclass, jobject);
+SECP256K1_API jobjectArray JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdh
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject, jlong ctx_l, jint publen);
+
 
 #ifdef __cplusplus
 }
diff --git a/src/java/org_bitcoin_Secp256k1Context.c b/src/java/org_bitcoin_Secp256k1Context.c
new file mode 100644
index 0000000000..a52939e7e7
--- /dev/null
+++ b/src/java/org_bitcoin_Secp256k1Context.c
@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include "org_bitcoin_Secp256k1Context.h"
+#include "include/secp256k1.h"
+
+SECP256K1_API jlong JNICALL Java_org_bitcoin_Secp256k1Context_secp256k1_1init_1context
+  (JNIEnv* env, jclass classObject)
+{
+  secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
+
+  (void)classObject;(void)env;
+
+  return (uintptr_t)ctx;
+}
+
diff --git a/src/java/org_bitcoin_Secp256k1Context.h b/src/java/org_bitcoin_Secp256k1Context.h
new file mode 100644
index 0000000000..0d2bc84b7f
--- /dev/null
+++ b/src/java/org_bitcoin_Secp256k1Context.h
@@ -0,0 +1,22 @@
+/* DO NOT EDIT THIS FILE - it is machine generated */
+#include <jni.h>
+#include "include/secp256k1.h"
+/* Header for class org_bitcoin_Secp256k1Context */
+
+#ifndef _Included_org_bitcoin_Secp256k1Context
+#define _Included_org_bitcoin_Secp256k1Context
+#ifdef __cplusplus
+extern "C" {
+#endif
+/*
+ * Class:     org_bitcoin_Secp256k1Context
+ * Method:    secp256k1_init_context
+ * Signature: ()J
+ */
+SECP256K1_API jlong JNICALL Java_org_bitcoin_Secp256k1Context_secp256k1_1init_1context
+  (JNIEnv *, jclass);
+
+#ifdef __cplusplus
+}
+#endif
+#endif