de.flexiprovider.ec
Class ECDSASignature

java.lang.Object
  |
  +--java.security.SignatureSpi
        |
        +--de.flexiprovider.api.Signature
              |
              +--de.flexiprovider.ec.ECDSASignature

Direct Known Subclasses:

ECDSASignature.Raw, ECDSASignature.SHA1, ECDSASignature.SHA224, ECDSASignature.SHA256, ECDSASignature.SHA384, ECDSASignature.SHA512

public abstract class ECDSASignature

extends Signature

This Signature class is used to provide applications the functionality of the digital signature algorithm ECDSA. Digital signatures are used for authentication and integrity assurance of digital data.

A Signature object can be used to generate and verify digital signatures. This specific signature ECDSA is based on the discrete logarithm problem in a group of points of an elliptic curve over a primefield GF(q), where q is the prime and GF is a common synonym for a galois field. For a description of the signing and verifying procedure see the documentation of this package.

Author:

Birgit Henhapl, Michele Boivin, Martin Döring

See Also:

ECPublicKey, ECPrivateKey, CurveParams

Inner Class Summary

static class	ECDSASignature.Raw ECDSA without message digest
static class	ECDSASignature.SHA1 ECDSA with SHA1
static class	ECDSASignature.SHA224 ECDSA with SHA224
static class	ECDSASignature.SHA256 ECDSA with SHA256
static class	ECDSASignature.SHA384 ECDSA with SHA384
static class	ECDSASignature.SHA512 ECDSA with SHA512

Fields inherited from class java.security.SignatureSpi

appRandom

Constructor Summary

protected

ECDSASignature(MessageDigest md) Constructor.

Method Summary

void	initSign(PrivateKey privateKey, SecureRandom random) Initializes this signature object with the specified private key and source of randomness for signing operations.
void	initVerify(PublicKey publicKey) Initializes this object for verification.
void	setParameters(AlgorithmParameterSpec params) Initialize this signature engine with the specified parameter set.
byte[]	sign() Return the signature of all the data updated so far.
void	update(byte input) Updates the data to be signed or verified using the specified byte.
void	update(byte[] input, int offset, int length) Updates the data to be signed or verified, using the specified array of bytes, starting at the specified offset.
boolean	verify(byte[] sigBytes) Verify the passed-in signature.

Methods inherited from class de.flexiprovider.api.Signature

engineGetParameter, engineInitSign, engineInitSign, engineInitVerify, engineSetParameter, engineSetParameter, engineSign, engineUpdate, engineUpdate, engineVerify, engineVerify, initSign, sign, update, verify, verify, verify

Methods inherited from class java.security.SignatureSpi

clone, engineSign

Methods inherited from class java.lang.Object

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

Constructor Detail

ECDSASignature

protected ECDSASignature(MessageDigest md)

Constructor. Set the message digest.

Parameters:

md - the message digest

Method Detail

initSign

public void initSign(PrivateKey privateKey,
                     SecureRandom random)
              throws InvalidKeyException

Initializes this signature object with the specified private key and source of randomness for signing operations.

Overrides:

initSign in class Signature

Parameters:

privateKey - the private key of the identity whose signature is going to be signed.

random - the source of randomness

Throws:

InvalidKeyException - If privateKey is an invalid key (invalid encoding, wrong length, uninitialized, etc).

initVerify

public void initVerify(PublicKey publicKey)
                throws InvalidKeyException

Initializes this object for verification. If this method is called again with a different argument, it negates the effect of this call.

Overrides:

initVerify in class Signature

Parameters:

publicKey - the public key of the identity whose signature is going to be verified.

Throws:

InvalidKeyException - If publicKey is an invalid key (invalid encoding, wrong length, uninitialized, etc).

setParameters

public void setParameters(AlgorithmParameterSpec params)
                   throws InvalidParameterException

Initialize this signature engine with the specified parameter set.

Overrides:

setParameters in class Signature

Parameters:

params - the parameters

Throws:

InvalidParameterException - if the given parameters are inappropriate for this signature engine

update

public void update(byte input)

Updates the data to be signed or verified using the specified byte.

Overrides:

update in class Signature

Parameters:

input - the byte to be updated.

update

public void update(byte[] input,
                   int offset,
                   int length)

Updates the data to be signed or verified, using the specified array of bytes, starting at the specified offset.

Overrides:

update in class Signature

Parameters:

input - the array of bytes.

offset - the offset to start from in the array of bytes.

length - the number of bytes to use, starting at offset.

sign

public byte[] sign()

Return the signature of all the data updated so far.

Overrides:

sign in class Signature

Returns:

the signature

verify

public boolean verify(byte[] sigBytes)
               throws SignatureException

Verify the passed-in signature.

Overrides:

verify in class Signature

Parameters:

sigBytes - the signature to be verified

Returns:

true if the signature is valid, false otherwise

Throws:

SignatureException - if this signature object is not initialized properly.