1 files changed, 446 insertions, 0 deletions
diff --git a/crypto/secp256k1/libsecp256k1/src/java/org/bitcoin/NativeSecp256k1.java b/crypto/secp256k1/libsecp256k1/src/java/org/bitcoin/NativeSecp256k1.java
new file mode 100644
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--- /dev/null
+++ b/crypto/secp256k1/libsecp256k1/src/java/org/bitcoin/NativeSecp256k1.java
@@ -0,0 +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.*;
+
+/**
+ * <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 {
+
+    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) throws AssertFailException{
+        Preconditions.checkArgument(data.length == 32 && signature.length <= 520 && pub.length <= 520);
+
+        ByteBuffer byteBuff = nativeECDSABuffer.get();
+        if (byteBuff == null || byteBuff.capacity() < 520) {
+            byteBuff = ByteBuffer.allocateDirect(520);
+            byteBuff.order(ByteOrder.nativeOrder());
+            nativeECDSABuffer.set(byteBuff);
+        }
+        byteBuff.rewind();
+        byteBuff.put(data);
+        byteBuff.put(signature);
+        byteBuff.put(pub);
+
+        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;
+    }
+
+    /**
+     * 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
+     */
+    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);
+
+}