3 files changed, 104 insertions, 0 deletions
diff --git a/src/secp256k1/src/java/org/bitcoin/NativeSecp256k1.java b/src/secp256k1/src/java/org/bitcoin/NativeSecp256k1.java
new file mode 100644
index 0000000000..90a498eaa2
--- /dev/null
+++ b/src/secp256k1/src/java/org/bitcoin/NativeSecp256k1.java
@@ -0,0 +1,60 @@
+package org.bitcoin;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+import com.google.common.base.Preconditions;
+
+
+/**
+ * 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
+ */
+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 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) {
+        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);
+            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;
+    }
+
+    /**
+     * @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
+     */
+    private static native int secp256k1_ecdsa_verify(ByteBuffer byteBuff);
+}
diff --git a/src/secp256k1/src/java/org_bitcoin_NativeSecp256k1.c b/src/secp256k1/src/java/org_bitcoin_NativeSecp256k1.c
new file mode 100644
index 0000000000..bb4cd70728
--- /dev/null
+++ b/src/secp256k1/src/java/org_bitcoin_NativeSecp256k1.c
@@ -0,0 +1,23 @@
+#include "org_bitcoin_NativeSecp256k1.h"
+#include "include/secp256k1.h"
+
+JNIEXPORT jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1verify
+  (JNIEnv* env, jclass classObject, jobject byteBufferObject)
+{
+	unsigned char* data = (unsigned char*) (*env)->GetDirectBufferAddress(env, byteBufferObject);
+	int sigLen = *((int*)(data + 32));
+	int pubLen = *((int*)(data + 32 + 4));
+
+	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));
+
+static void __javasecp256k1_attach(void) {
+	secp256k1_start(SECP256K1_START_VERIFY);
+}
+
+static void __javasecp256k1_detach(void) {
+	secp256k1_stop();
+}
diff --git a/src/secp256k1/src/java/org_bitcoin_NativeSecp256k1.h b/src/secp256k1/src/java/org_bitcoin_NativeSecp256k1.h
new file mode 100644
index 0000000000..d7fb004fa8
--- /dev/null
+++ b/src/secp256k1/src/java/org_bitcoin_NativeSecp256k1.h
@@ -0,0 +1,21 @@
+/* DO NOT EDIT THIS FILE - it is machine generated */
+#include <jni.h>
+/* Header for class org_bitcoin_NativeSecp256k1 */
+
+#ifndef _Included_org_bitcoin_NativeSecp256k1
+#define _Included_org_bitcoin_NativeSecp256k1
+#ifdef __cplusplus
+extern "C" {
+#endif
+/*
+ * Class:     org_bitcoin_NativeSecp256k1
+ * Method:    secp256k1_ecdsa_verify
+ * Signature: (Ljava/nio/ByteBuffer;)I
+ */
+JNIEXPORT jint JNICALL Java_org_bitcoin_NativeSecp256k1_secp256k1_1ecdsa_1verify
+  (JNIEnv *, jclass, jobject);
+
+#ifdef __cplusplus
+}
+#endif
+#endif