gnu.crypto.sig

Class BaseSignature

Implemented Interfaces:
Cloneable, ISignature
Known Direct Subclasses:
DSSSignature, RSAPKCS1V1_5Signature, RSAPSSSignature

public abstract class BaseSignature
extends Object
implements ISignature

A base abstract class to facilitate implementations of concrete Signatures.
Version:
$Revision: 1.8 $

Field Summary

protected IMessageDigest
md
The underlying message digest instance for this signature scheme.
protected PrivateKey
privateKey
The private key to use when generating signatures (signing).
protected PublicKey
publicKey
The public key to use when verifying signatures.
protected String
schemeName
The canonical name of this signature scheme.

Fields inherited from interface gnu.crypto.sig.ISignature

SIGNER_KEY, SOURCE_OF_RANDOMNESS, VERIFIER_KEY

Constructor Summary

BaseSignature(String schemeName, IMessageDigest md)
Trivial constructor.

Method Summary

abstract Object
clone()
Returns a clone copy of this instance.
protected abstract Object
generateSignature()
protected void
init()
Initialises the internal fields of this instance.
String
name()
Returns the canonical name of this signature scheme.
protected void
nextRandomBytes(byte[] buffer)
Fills the designated byte array with random data.
protected abstract void
setupForSigning(PrivateKey key)
protected abstract void
setupForVerification(PublicKey key)
void
setupSign(Map attributes)
Initialises this instance for signature generation.
void
setupVerify(Map attributes)
Initialises this instance for signature verification.
Object
sign()
Terminates a signature generation phase by digesting and processing the context of the underlying message digest algorithm instance.
void
update(byte b)
Digests one byte of a message for signing or verification purposes.
void
update(byte[] b, int off, int len)
Digests a sequence of bytes from a message for signing or verification purposes.
boolean
verify(Object sig)
Terminates a signature verification phase by digesting and processing the context of the underlying message digest algorithm instance.
protected abstract boolean
verifySignature(Object signature)

Field Details

md

protected IMessageDigest md
The underlying message digest instance for this signature scheme.

privateKey

protected PrivateKey privateKey
The private key to use when generating signatures (signing).

publicKey

protected PublicKey publicKey
The public key to use when verifying signatures.

schemeName

protected String schemeName
The canonical name of this signature scheme.

Constructor Details

BaseSignature

protected BaseSignature(String schemeName,
                        IMessageDigest md)
Trivial constructor.
Parameters:
schemeName - the name of this signature scheme.
md - the underlying instance of the message digest algorithm.

Method Details

clone

public abstract Object clone()
Returns a clone copy of this instance.
Specified by:
clone in interface ISignature
Returns:
a clone copy of this instance.

generateSignature

protected abstract Object generateSignature()
            throws IllegalStateException

init

protected void init()
Initialises the internal fields of this instance.

name

public String name()
Returns the canonical name of this signature scheme.
Specified by:
name in interface ISignature
Returns:
the canonical name of this instance.

nextRandomBytes

protected void nextRandomBytes(byte[] buffer)
Fills the designated byte array with random data.
Parameters:
buffer - the byte array to fill with random data.

setupForSigning

protected abstract void setupForSigning(PrivateKey key)
            throws IllegalArgumentException

setupForVerification

protected abstract void setupForVerification(PublicKey key)
            throws IllegalArgumentException

setupSign

public void setupSign(Map attributes)
            throws IllegalArgumentException
Initialises this instance for signature generation.
Specified by:
setupSign in interface ISignature
Parameters:
attributes - the attributes to use for setting up this instance.

setupVerify

public void setupVerify(Map attributes)
            throws IllegalArgumentException
Initialises this instance for signature verification.
Specified by:
setupVerify in interface ISignature
Parameters:
attributes - the attributes to use for setting up this instance.

sign

public Object sign()
Terminates a signature generation phase by digesting and processing the context of the underlying message digest algorithm instance.
Specified by:
sign in interface ISignature
Returns:
a Object representing the native output of the signature scheme implementation.

update

public void update(byte b)
Digests one byte of a message for signing or verification purposes.
Specified by:
update in interface ISignature
Parameters:
b - the message byte to digest.

update

public void update(byte[] b,
                   int off,
                   int len)
Digests a sequence of bytes from a message for signing or verification purposes.
Specified by:
update in interface ISignature
Parameters:

verify

public boolean verify(Object sig)
Terminates a signature verification phase by digesting and processing the context of the underlying message digest algorithm instance.
Specified by:
verify in interface ISignature
Parameters:
Returns:
true iff the outpout of the verification phase confirms that the designated signature object has been generated using the corresponding public key of the recepient.

verifySignature

protected abstract boolean verifySignature(Object signature)
            throws IllegalStateException

Copyright © 2001, 2002, 2003 Free Software Foundation, Inc. All Rights Reserved.