org.bouncycastle.crypto.signers

Class ECDSASigner

java.lang.Object

org.bouncycastle.crypto.signers.ECDSASigner

All Implemented Interfaces:

DSA, ECConstants

public class ECDSASigner
extends java.lang.Object
implements ECConstants, DSA

EC-DSA as described in X9.62

Field Summary

Fields inherited from interface org.bouncycastle.math.ec.ECConstants

EIGHT, FOUR, ONE, THREE, TWO, ZERO

Constructor Summary

Constructors

Constructor and Description
ECDSASigner() Default configuration, random K values.
ECDSASigner(DSAKCalculator kCalculator) Configuration with an alternate, possibly deterministic calculator of K.

Method Summary

Modifier and Type	Method and Description
protected java.math.BigInteger	calculateE(java.math.BigInteger n, byte[] message)
protected ECMultiplier	createBasePointMultiplier()
java.math.BigInteger[]	generateSignature(byte[] message) generate a signature for the given message using the key we were initialised with.
protected ECFieldElement	getDenominator(int coordinateSystem, ECPoint p)
void	init(boolean forSigning, CipherParameters param) initialise the signer for signature generation or signature verification.
protected java.security.SecureRandom	initSecureRandom(boolean needed, java.security.SecureRandom provided)
boolean	verifySignature(byte[] message, java.math.BigInteger r, java.math.BigInteger s) return true if the value r and s represent a DSA signature for the passed in message (for standard DSA the message should be a SHA-1 hash of the real message to be verified).

Methods inherited from class java.lang.Object

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

Constructor Detail

ECDSASigner

public ECDSASigner()

Default configuration, random K values.

ECDSASigner

public ECDSASigner(DSAKCalculator kCalculator)

Configuration with an alternate, possibly deterministic calculator of K.

Parameters:

kCalculator - a K value calculator.

Method Detail

init

public void init(boolean forSigning,
                 CipherParameters param)

Description copied from interface: DSA

initialise the signer for signature generation or signature verification.

Specified by:

init in interface DSA

Parameters:

forSigning - true if we are generating a signature, false otherwise.

param - key parameters for signature generation.

generateSignature

public java.math.BigInteger[] generateSignature(byte[] message)

generate a signature for the given message using the key we were initialised with. For conventional DSA the message should be a SHA-1 hash of the message of interest.

Specified by:

generateSignature in interface DSA

Parameters:

message - the message that will be verified later.

Returns:

two big integers representing the r and s values respectively.

verifySignature

public boolean verifySignature(byte[] message,
                               java.math.BigInteger r,
                               java.math.BigInteger s)

return true if the value r and s represent a DSA signature for the passed in message (for standard DSA the message should be a SHA-1 hash of the real message to be verified).

Specified by:

verifySignature in interface DSA

Parameters:

message - the message that was supposed to have been signed.

r - the r signature value.

s - the s signature value.

calculateE

protected java.math.BigInteger calculateE(java.math.BigInteger n,
                                          byte[] message)

createBasePointMultiplier

protected ECMultiplier createBasePointMultiplier()

getDenominator

protected ECFieldElement getDenominator(int coordinateSystem,
                                        ECPoint p)

initSecureRandom

protected java.security.SecureRandom initSecureRandom(boolean needed,
                                                      java.security.SecureRandom provided)