package gnu.crypto.hash;
// ----------------------------------------------------------------------------
// $Id: IMessageDigest.java,v 1.11 2005/10/06 04:24:14 rsdio Exp $
//
// Copyright (C) 2001, 2002, 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.,
// 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301
// 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.
// ----------------------------------------------------------------------------
/**
* <p>The basic visible methods of any hash algorithm.</p>
*
* <p>A hash (or message digest) algorithm produces its output by iterating a
* basic compression function on blocks of data.</p>
*
* @version $Revision: 1.11 $
*/
public interface IMessageDigest extends Cloneable {
// Constants
// -------------------------------------------------------------------------
// Methods
// -------------------------------------------------------------------------
/**
* <p>Returns the canonical name of this algorithm.</p>
*
* @return the canonical name of this instance.
*/
String name();
/**
* <p>Returns the output length in bytes of this message digest algorithm.</p>
*
* @return the output length in bytes of this message digest algorithm.
*/
int hashSize();
/**
* <p>Returns the algorithm's (inner) block size in bytes.</p>
*
* @return the algorithm's inner block size in bytes.
*/
int blockSize();
/**
* <p>Continues a message digest operation using the input byte.</p>
*
* @param b the input byte to digest.
*/
void update(byte b);
/**
* <p>Continues a message digest operation, by filling the buffer, processing
* data in the algorithm's HASH_SIZE-bit block(s), updating the context and
* count, and buffering the remaining bytes in buffer for the next
* operation.</p>
*
* @param in the input block.
*/
void update(byte[] in);
/**
* <p>Continues a message digest operation, by filling the buffer, processing
* data in the algorithm's HASH_SIZE-bit block(s), updating the context and
* count, and buffering the remaining bytes in buffer for the next
* operation.</p>
*
* @param in the input block.
* @param offset start of meaningful bytes in input block.
* @param length number of bytes, in input block, to consider.
*/
void update(byte[] in, int offset, int length);
/**
* <p>Completes the message digest by performing final operations such as
* padding and resetting the instance.</p>
*
* @return the array of bytes representing the hash value.
*/
byte[] digest();
/**
* <p>Resets the current context of this instance clearing any eventually cached
* intermediary values.</p>
*/
void reset();
/**
* <p>A basic test. Ensures that the digest of a pre-determined message is equal
* to a known pre-computed value.</p>
*
* @return <tt>true</tt> if the implementation passes a basic self-test.
* Returns <tt>false</tt> otherwise.
*/
boolean selfTest();
/**
* <p>Returns a clone copy of this instance.</p>
*
* @return a clone copy of this instance.
*/
Object clone();
}