org.spongycastle.crypto.signers

Class ECNRSigner

java.lang.Object

org.spongycastle.crypto.signers.ECNRSigner

All Implemented Interfaces:

DSA

public class ECNRSigner
extends java.lang.Object
implements DSA

EC-NR as described in IEEE 1363-2000

Constructor Summary

Constructors

Constructor and Description
ECNRSigner()

Method Summary

Modifier and Type	Method and Description
java.math.BigInteger[]	generateSignature(byte[] digest) generate a signature for the given message using the key we were initialised with.
void	init(boolean forSigning, CipherParameters param) initialise the signer for signature generation or signature verification.
boolean	verifySignature(byte[] digest, java.math.BigInteger r, java.math.BigInteger s) return true if the value r and s represent a signature for the message passed in.

Methods inherited from class java.lang.Object

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

Constructor Detail

ECNRSigner

public ECNRSigner()

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[] digest)

generate a signature for the given message using the key we were initialised with. Generally, the order of the curve should be at least as long as the hash of the message of interest, and with ECNR it *must* be at least as long.

Specified by:

generateSignature in interface DSA

Parameters:

digest - the digest to be signed.

Returns:

two big integers representing the r and s values respectively.

Throws:

DataLengthException - if the digest is longer than the key allows

verifySignature

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

return true if the value r and s represent a signature for the message passed in. Generally, the order of the curve should be at least as long as the hash of the message of interest, and with ECNR, it *must* be at least as long. But just in case the signer applied mod(n) to the longer digest, this implementation will apply mod(n) during verification.

Specified by:

verifySignature in interface DSA

Parameters:

digest - the digest to be verified.

r - the r value of the signature.

s - the s value of the signature.

Throws:

DataLengthException - if the digest is longer than the key allows