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package gnu.crypto.sig;
// ----------------------------------------------------------------------------
// $Id: ISignature.java,v 1.7 2003/10/25 03:57:20 raif Exp $
//
// Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING. If not, write to the
//
// Free Software Foundation Inc.,
// 59 Temple Place - Suite 330,
// Boston, MA 02111-1307
// USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library. Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module. An independent module is a module which is
// not derived from or based on this library. If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so. If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------
import java.util.Map;
/**
* The visible methods of every signature-with-appendix scheme.
*
* The Handbook of Applied Cryptography (HAC), by A. Menezes & al. states:
* "Digital signature schemes which require the message as input to the
* verification algorithm are called digital signature schemes with
* appendix. ... They rely on cryptographic hash functions rather than
* customised redundancy functions, and are less prone to existential forgery
* attacks."
*
* References:
*
* - Handbook of Applied
* Cryptography, Alfred J. Menezes, Paul C. van Oorschot and Scott A.
* Vanstone. Section 11.2.2 Digital signature schemes with appendix.
*
*
* @version $Revision: 1.7 $
*/
public interface ISignature extends Cloneable {
// Constants
// -------------------------------------------------------------------------
/** Property name of the verifier's public key. */
public static final String VERIFIER_KEY = "gnu.crypto.sig.public.key";
/** Property name of the signer's private key. */
public static final String SIGNER_KEY = "gnu.crypto.sig.private.key";
/**
* Property name of an optional {@link java.security.SecureRandom},
* {@link java.util.Random}, or {@link gnu.crypto.prng.IRandom} instance to
* use. The default is to use a classloader singleton from
* {@link gnu.crypto.util.PRNG}.
*/
public static final String SOURCE_OF_RANDOMNESS = "gnu.crypto.sig.prng";
// Methods
// -------------------------------------------------------------------------
/**
* Returns the canonical name of this signature scheme.
*
* @return the canonical name of this instance.
*/
String name();
/**
* Initialises this instance for signature verification.
*
* @param attributes the attributes to use for setting up this instance.
* @throws IllegalArgumentException if the designated public key is not
* appropriate for this signature scheme.
* @see #SOURCE_OF_RANDOMNESS
* @see #VERIFIER_KEY
*/
void setupVerify(Map attributes) throws IllegalArgumentException;
/**
* Initialises this instance for signature generation.
*
* @param attributes the attributes to use for setting up this instance.
* @throws IllegalArgumentException if the designated private key is not
* appropriate for this signature scheme.
* @see #SOURCE_OF_RANDOMNESS
* @see #SIGNER_KEY
*/
void setupSign(Map attributes) throws IllegalArgumentException;
/**
* Digests one byte of a message for signing or verification purposes.
*
* @param b the message byte to digest.
* @throws IllegalStateException if this instance was not setup for
* signature generation/verification.
*/
void update(byte b) throws IllegalStateException;
/**
* Digests a sequence of bytes from a message for signing or verification
* purposes.
*
* @param buffer the byte sequence to consider.
* @param offset the byte poisition in buffer of the first byte
* to consider.
* @param length the number of bytes in buffer starting from the
* byte at index offset to digest.
* @throws IllegalStateException if this instance was not setup for
* signature generation/verification.
*/
void update(byte[] buffer, int offset, int length)
throws IllegalStateException;
/**
* Terminates a signature generation phase by digesting and processing the
* context of the underlying message digest algorithm instance.
*
* @return a {@link Object} representing the native output of the signature
* scheme implementation.
* @throws IllegalStateException if this instance was not setup for
* signature generation.
*/
Object sign() throws IllegalStateException;
/**
* Terminates a signature verification phase by digesting and processing
* the context of the underlying message digest algorithm instance.
*
* @param signature a native signature object previously generated by an
* invocation of the sign() method.
* @return 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.
* @throws IllegalStateException if this instance was not setup for
* signature verification.
*/
boolean verify(Object signature) throws IllegalStateException;
/**
* Returns a clone copy of this instance.
*
* @return a clone copy of this instance.
*/
Object clone();
}