org.web3j.crypto

Class Sign

java.lang.Object

org.web3j.crypto.Sign

public class Sign
extends java.lang.Object

Transaction signing logic.

Adapted from the BitcoinJ ECKey implementation.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Sign.SignatureData

Field Summary

Fields

Modifier and Type	Field and Description
static org.bouncycastle.asn1.x9.X9ECParameters	CURVE_PARAMS

Constructor Summary

Constructors

Constructor and Description
Sign()

Method Summary

Modifier and Type	Method and Description
static byte[]	getEthereumMessageHash(byte[] message)
static int	getRecId(Sign.SignatureData signatureData, long chainId) Returns recovery ID.
static byte[]	getVFromRecId(int recId) Returns the header 'v'.
static java.math.BigInteger	publicFromPoint(byte[] bits) Returns public key point from the given curve.
static java.math.BigInteger	publicKeyFromPrivate(java.math.BigInteger privKey) Returns public key from the given private key.
static org.bouncycastle.math.ec.ECPoint	publicPointFromPrivate(java.math.BigInteger privKey) Returns public key point from the given private key.
static java.math.BigInteger	recoverFromSignature(int recId, ECDSASignature sig, byte[] message) Given the components of a signature and a selector value, recover and return the public key that generated the signature according to the algorithm in SEC1v2 section 4.1.6.
static java.math.BigInteger	signedMessageHashToKey(byte[] messageHash, Sign.SignatureData signatureData) Given an arbitrary message hash and an Ethereum message signature encoded in bytes, returns the public key that was used to sign it.
static java.math.BigInteger	signedMessageToKey(byte[] message, Sign.SignatureData signatureData) Given an arbitrary piece of text and an Ethereum message signature encoded in bytes, returns the public key that was used to sign it.
static java.math.BigInteger	signedPrefixedMessageToKey(byte[] message, Sign.SignatureData signatureData) Given an arbitrary message and an Ethereum message signature encoded in bytes, returns the public key that was used to sign it.
static Sign.SignatureData	signMessage(byte[] message, ECKeyPair keyPair)
static Sign.SignatureData	signMessage(byte[] message, ECKeyPair keyPair, boolean needToHash)
static Sign.SignatureData	signPrefixedMessage(byte[] message, ECKeyPair keyPair)

Methods inherited from class java.lang.Object

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

Field Detail

CURVE_PARAMS

public static final org.bouncycastle.asn1.x9.X9ECParameters CURVE_PARAMS

Constructor Detail

Sign

public Sign()

Method Detail

getEthereumMessageHash

public static byte[] getEthereumMessageHash(byte[] message)

signPrefixedMessage

public static Sign.SignatureData signPrefixedMessage(byte[] message,
                                                     ECKeyPair keyPair)

signMessage

public static Sign.SignatureData signMessage(byte[] message,
                                             ECKeyPair keyPair)

signMessage

public static Sign.SignatureData signMessage(byte[] message,
                                             ECKeyPair keyPair,
                                             boolean needToHash)

recoverFromSignature

public static java.math.BigInteger recoverFromSignature(int recId,
                                                        ECDSASignature sig,
                                                        byte[] message)

Given the components of a signature and a selector value, recover and return the public key that generated the signature according to the algorithm in SEC1v2 section 4.1.6.

The recId is an index from 0 to 3 which indicates which of the 4 possible keys is the correct one. Because the key recovery operation yields multiple potential keys, the correct key must either be stored alongside the signature, or you must be willing to try each recId in turn until you find one that outputs the key you are expecting.

If this method returns null it means recovery was not possible and recId should be iterated.

Given the above two points, a correct usage of this method is inside a for loop from 0 to 3, and if the output is null OR a key that is not the one you expect, you try again with the next recId.

Parameters:

recId - Which possible key to recover.

sig - the R and S components of the signature, wrapped.

message - Hash of the data that was signed.

Returns:

An ECKey containing only the public part, or null if recovery wasn't possible.

signedMessageToKey

public static java.math.BigInteger signedMessageToKey(byte[] message,
                                                      Sign.SignatureData signatureData)
                                               throws java.security.SignatureException

Given an arbitrary piece of text and an Ethereum message signature encoded in bytes, returns the public key that was used to sign it. This can then be compared to the expected public key to determine if the signature was correct.

Parameters:

message - RLP encoded message.

signatureData - The message signature components

Returns:

the public key used to sign the message

Throws:

java.security.SignatureException - If the public key could not be recovered or if there was a signature format error.

signedPrefixedMessageToKey

public static java.math.BigInteger signedPrefixedMessageToKey(byte[] message,
                                                              Sign.SignatureData signatureData)
                                                       throws java.security.SignatureException

Given an arbitrary message and an Ethereum message signature encoded in bytes, returns the public key that was used to sign it. This can then be compared to the expected public key to determine if the signature was correct.

Parameters:

message - The message.

signatureData - The message signature components

Returns:

the public key used to sign the message

Throws:

java.security.SignatureException - If the public key could not be recovered or if there was a signature format error.

signedMessageHashToKey

public static java.math.BigInteger signedMessageHashToKey(byte[] messageHash,
                                                          Sign.SignatureData signatureData)
                                                   throws java.security.SignatureException

Given an arbitrary message hash and an Ethereum message signature encoded in bytes, returns the public key that was used to sign it. This can then be compared to the expected public key to determine if the signature was correct.

Parameters:

messageHash - The message hash.

signatureData - The message signature components

Returns:

the public key used to sign the message

Throws:

java.security.SignatureException - If the public key could not be recovered or if there was a signature format error.

getRecId

public static int getRecId(Sign.SignatureData signatureData,
                           long chainId)

Returns recovery ID.

Parameters:

signatureData - The message signature components

chainId - of the network

Returns:

int recovery ID

getVFromRecId

public static byte[] getVFromRecId(int recId)

Returns the header 'v'.

Parameters:

recId - The recovery id.

Returns:

byte[] header 'v'.

publicKeyFromPrivate

public static java.math.BigInteger publicKeyFromPrivate(java.math.BigInteger privKey)

Returns public key from the given private key.

Parameters:

privKey - the private key to derive the public key from

Returns:

BigInteger encoded public key

publicPointFromPrivate

public static org.bouncycastle.math.ec.ECPoint publicPointFromPrivate(java.math.BigInteger privKey)

Returns public key point from the given private key.

Parameters:

privKey - the private key to derive the public key from

Returns:

ECPoint public key

publicFromPoint

public static java.math.BigInteger publicFromPoint(byte[] bits)

Returns public key point from the given curve.

Parameters:

bits - representing the point on the curve

Returns:

BigInteger encoded public key