org.bitcoin

Class NativeSecp256k1

java.lang.Object

org.bitcoin.NativeSecp256k1

public class NativeSecp256k1
extends java.lang.Object

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/bitcoin/secp256k1

To build secp256k1 for use with bitcoinj, run `./configure --enable-jni --enable-experimental --enable-module-schnorr --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

Constructor Summary

Constructors

Constructor and Description
NativeSecp256k1()

Method Summary

Modifier and Type	Method and Description
static void	cleanup() libsecp256k1 Cleanup - This destroys the secp256k1 context object This should be called at the end of the program for proper cleanup of the context.
static long	cloneContext()
static byte[]	computePubkey(byte[] seckey) libsecp256k1 Compute Pubkey - computes public key from secret key
static byte[]	createECDHSecret(byte[] seckey, byte[] pubkey) libsecp256k1 create ECDH secret - constant time ECDH calculation
static byte[]	privKeyTweakAdd(byte[] privkey, byte[] tweak) libsecp256k1 PrivKey Tweak-Add - Tweak privkey by adding to it
static byte[]	privKeyTweakMul(byte[] privkey, byte[] tweak) libsecp256k1 PrivKey Tweak-Mul - Tweak privkey by multiplying to it
static byte[]	pubKeyTweakAdd(byte[] pubkey, byte[] tweak) libsecp256k1 PubKey Tweak-Add - Tweak pubkey by adding to it
static byte[]	pubKeyTweakMul(byte[] pubkey, byte[] tweak) libsecp256k1 PubKey Tweak-Mul - Tweak pubkey by multiplying to it
static boolean	randomize(byte[] seed) libsecp256k1 randomize - updates the context randomization
static byte[]	schnorrSign(byte[] data, byte[] sec)
static boolean	secKeyVerify(byte[] seckey) libsecp256k1 Seckey Verify - returns 1 if valid, 0 if invalid
static byte[]	sign(byte[] data, byte[] sec) libsecp256k1 Create an ECDSA signature.
static boolean	verify(byte[] data, byte[] signature, byte[] pub) Verifies the given secp256k1 signature in native code.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NativeSecp256k1

public NativeSecp256k1()

Method Detail

verify

public static boolean verify(byte[] data,
                             byte[] signature,
                             byte[] pub)
                      throws NativeSecp256k1Util.AssertFailException

Verifies the given secp256k1 signature in native code. Calling when enabled == false is undefined (probably library not loaded)

Parameters:

data - The data which was signed, must be exactly 32 bytes

signature - The signature

pub - The public key which did the signing

Throws:

NativeSecp256k1Util.AssertFailException

sign

public static byte[] sign(byte[] data,
                          byte[] sec)
                   throws NativeSecp256k1Util.AssertFailException

libsecp256k1 Create an ECDSA signature.

Parameters:

data - Message hash, 32 bytes

sec - Secret key, 32 bytes

Returns:

sig byte array of signature

Throws:

NativeSecp256k1Util.AssertFailException

secKeyVerify

public static boolean secKeyVerify(byte[] seckey)

libsecp256k1 Seckey Verify - returns 1 if valid, 0 if invalid

Parameters:

seckey - ECDSA Secret key, 32 bytes

computePubkey

public static byte[] computePubkey(byte[] seckey)
                            throws NativeSecp256k1Util.AssertFailException

libsecp256k1 Compute Pubkey - computes public key from secret key

Parameters:

seckey - ECDSA Secret key, 32 bytes

Returns:

pubkey ECDSA Public key, 33 or 65 bytes

Throws:

NativeSecp256k1Util.AssertFailException

cleanup

public static void cleanup()

libsecp256k1 Cleanup - This destroys the secp256k1 context object This should be called at the end of the program for proper cleanup of the context.

cloneContext

public static long cloneContext()

privKeyTweakMul

public static byte[] privKeyTweakMul(byte[] privkey,
                                     byte[] tweak)
                              throws NativeSecp256k1Util.AssertFailException

libsecp256k1 PrivKey Tweak-Mul - Tweak privkey by multiplying to it

Parameters:

tweak - some bytes to tweak with

privkey - 32-byte seckey

Throws:

NativeSecp256k1Util.AssertFailException

privKeyTweakAdd

public static byte[] privKeyTweakAdd(byte[] privkey,
                                     byte[] tweak)
                              throws NativeSecp256k1Util.AssertFailException

libsecp256k1 PrivKey Tweak-Add - Tweak privkey by adding to it

Parameters:

tweak - some bytes to tweak with

privkey - 32-byte seckey

Throws:

NativeSecp256k1Util.AssertFailException

pubKeyTweakAdd

public static byte[] pubKeyTweakAdd(byte[] pubkey,
                                    byte[] tweak)
                             throws NativeSecp256k1Util.AssertFailException

libsecp256k1 PubKey Tweak-Add - Tweak pubkey by adding to it

Parameters:

tweak - some bytes to tweak with

pubkey - 32-byte seckey

Throws:

NativeSecp256k1Util.AssertFailException

pubKeyTweakMul

public static byte[] pubKeyTweakMul(byte[] pubkey,
                                    byte[] tweak)
                             throws NativeSecp256k1Util.AssertFailException

libsecp256k1 PubKey Tweak-Mul - Tweak pubkey by multiplying to it

Parameters:

tweak - some bytes to tweak with

pubkey - 32-byte seckey

Throws:

NativeSecp256k1Util.AssertFailException

createECDHSecret

public static byte[] createECDHSecret(byte[] seckey,
                                      byte[] pubkey)
                               throws NativeSecp256k1Util.AssertFailException

libsecp256k1 create ECDH secret - constant time ECDH calculation

Parameters:

seckey - byte array of secret key used in exponentiaion

pubkey - byte array of public key used in exponentiaion

Throws:

NativeSecp256k1Util.AssertFailException

randomize

public static boolean randomize(byte[] seed)
                         throws NativeSecp256k1Util.AssertFailException

libsecp256k1 randomize - updates the context randomization

Parameters:

seed - 32-byte random seed

Throws:

NativeSecp256k1Util.AssertFailException

schnorrSign

public static byte[] schnorrSign(byte[] data,
                                 byte[] sec)
                          throws NativeSecp256k1Util.AssertFailException

Throws:

NativeSecp256k1Util.AssertFailException