iaik.security.ecc.ecdsa
Class ECDSASignature

java.lang.Object
  java.security.SignatureSpi
      java.security.Signature
          iaik.security.ecc.ecdsa.ECDSASignature

Direct Known Subclasses:

RIPEMD160withECDSASignature, SHA224withECDSASignature, SHA256withECDSASignature, SHA384withECDSASignature, SHA512withECDSASignature, WHIRLPOOLwithECDSASignature

public class ECDSASignature

extends java.security.Signature

The signature class for the ECDSA algorithm. It is responsible for signature creation and verification. Use this class with the JCE/JCA framework.

Field Summary

protected java.security.MessageDigest	md_ The message digest.
protected ECPrivateKey	privateKey_ The private key, used for signing.
protected ECPublicKey	publicKey_ The public key used for verification.
protected java.security.SecureRandom	secureRandom_ Source of randomness.

Fields inherited from class java.security.Signature

SIGN, state, UNINITIALIZED, VERIFY

Fields inherited from class java.security.SignatureSpi

appRandom

Constructor Summary

ECDSASignature()
Applications shouldn't use this constructor, but the Signature.getInstance("ECDSA") method.

Method Summary

protected java.lang.Object	engineGetParameter(java.lang.String param) Method not implemented.
protected void	engineInitSign(java.security.PrivateKey privateKey) Initializes the engine for signature creation.
protected void	engineInitSign(java.security.PrivateKey privateKey, java.security.SecureRandom random) Initializes the engine for signature creation.
protected void	engineInitVerify(java.security.PublicKey publicKey) Initializes the engine for signature verification.
protected void	engineSetParameter(java.security.spec.AlgorithmParameterSpec params) Method not implemented.
protected void	engineSetParameter(java.lang.String param, java.lang.Object value) Method not implemented.
protected byte[]	engineSign() Implements the sign algorithm according to the rules: k = random([1,n-1]) kP = (x1,y1) r = x1 mod n e = H(M) s = k1(e+dr) mod n Signature: (r,s)
protected void	engineUpdate(byte b) Updates the hash to be signed or verified.
protected void	engineUpdate(byte[] b, int off, int len) SPI: Updates the data to be signed or verified with the specified number of bytes, beginning at the specified offset within the given byte array.
protected boolean	engineVerify(byte[] sigBytes) Verifies a given signature according to the following rules: extract r and s from the given byte[] if r is not an integer in the interval [1, n-1] reject sig.

Methods inherited from class java.security.Signature

clone, getAlgorithm, getInstance, getInstance, getInstance, getParameter, getParameters, getProvider, initSign, initSign, initVerify, initVerify, setParameter, setParameter, sign, sign, toString, update, update, update, verify, verify

Methods inherited from class java.security.SignatureSpi

engineGetParameters, engineSign, engineVerify

Methods inherited from class java.lang.Object

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

Field Detail

md_

protected java.security.MessageDigest md_

The message digest.

privateKey_

protected ECPrivateKey privateKey_

The private key, used for signing.

publicKey_

protected ECPublicKey publicKey_

The public key used for verification.

secureRandom_

protected java.security.SecureRandom secureRandom_

Source of randomness.

Constructor Detail

ECDSASignature

public ECDSASignature()
               throws java.security.NoSuchAlgorithmException

Applications shouldn't use this constructor, but the Signature.getInstance("ECDSA") method.

Method Detail

engineGetParameter

protected java.lang.Object engineGetParameter(java.lang.String param)
                                       throws java.security.InvalidParameterException

Method not implemented. Just throws an InvalidParameterException.

Throws:

java.security.InvalidParameterException

engineInitSign

protected void engineInitSign(java.security.PrivateKey privateKey)
                       throws java.security.InvalidKeyException

Initializes the engine for signature creation.

Parameters:

privateKey - the ECDSA private key used for signing.

Throws:

java.security.InvalidKeyException - if a key encoding error occurs.

engineInitSign

protected void engineInitSign(java.security.PrivateKey privateKey,
                              java.security.SecureRandom random)
                       throws java.security.InvalidKeyException

Initializes the engine for signature creation.

Parameters:

privateKey - the ECDSA private key used for signing.

random - the source for randomness.

Throws:

java.security.InvalidKeyException - if a key encoding error occurs.

engineInitVerify

protected void engineInitVerify(java.security.PublicKey publicKey)
                         throws java.security.InvalidKeyException

Initializes the engine for signature verification.

Parameters:

publicKey - the ECDSA public key used for the signature verification.

Throws:

java.security.InvalidKeyException - if a key encoding error occurs.

engineSetParameter

protected void engineSetParameter(java.security.spec.AlgorithmParameterSpec params)
                           throws java.security.InvalidAlgorithmParameterException

Method not implemented. Just throws an InvalidAlgorithmParameterException.

Throws:

java.security.InvalidAlgorithmParameterException

engineSetParameter

protected void engineSetParameter(java.lang.String param,
                                  java.lang.Object value)
                           throws java.security.InvalidParameterException

Method not implemented. Just throws an InvalidParameterException.

Throws:

java.security.InvalidParameterException

engineSign

protected byte[] engineSign()
                     throws java.security.SignatureException

Implements the sign algorithm according to the rules:

1. k = random([1,n-1])
2. kP = (x1,y1)
3. r = x1 mod n
4. e = H(M)
5. s = k¹(e+dr) mod n
6. Signature: (r,s)

Returns:

(r,s) as byte array

Throws:

java.security.SignatureException

engineUpdate

protected void engineUpdate(byte b)

Updates the hash to be signed or verified.

Parameters:

b - the "new" byte.

engineUpdate

protected void engineUpdate(byte[] b,
                            int off,
                            int len)

SPI: Updates the data to be signed or verified with the specified number of bytes, beginning at the specified offset within the given byte array.

Parameters:

b - the byte array holding the data to be used for this update operation.

off - the offset, indicating the start position within the given byte array.

len - the number of bytes to be obtained from the given byte array, starting at the given position.

engineVerify

protected boolean engineVerify(byte[] sigBytes)
                        throws java.security.SignatureException

Verifies a given signature according to the following rules:

1. extract r and s from the given byte[]
2. if r is not an integer in the interval [1, n-1] reject sig.
3. if s is not an integer in the interval [1, n-1] reject sig.
4. compute digest e = SHA-1(M)
5. c = s^(-1) mod n
6. u1 = e*c mod n
7. u2 = r*c mod n
8. (x1, y1) = u1*G + u2*Q
9. if (x1, y1) is the point at infinity, then reject sig.
10. convert x1 to integer x
11. v = x mod n
12. if r = v then accept sig.
13. if r != v then reject sig.

Parameters:

sigBytes - the encoded r and s values of the signature.

Returns:

true if the signature is valid.

Throws:

java.security.SignatureException - if an error occurs when verifying the signature.