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package gnu.crypto.hash;

// ----------------------------------------------------------------------------
// $Id: Sha160.java,v 1.9 2002/12/03 09:48:58 raif 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.,
//    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
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// you permission to link this library with independent modules to
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// ----------------------------------------------------------------------------

import gnu.crypto.Registry;
import gnu.crypto.util.Util;

/**
 * 

The Secure Hash Algorithm (SHA-1) is required for use with the Digital * Signature Algorithm (DSA) as specified in the Digital Signature Standard * (DSS) and whenever a secure hash algorithm is required for federal * applications. For a message of length less than 2^64 bits, the SHA-1 * produces a 160-bit condensed representation of the message called a message * digest. The message digest is used during generation of a signature for the * message. The SHA-1 is also used to compute a message digest for the received * version of the message during the process of verifying the signature. Any * change to the message in transit will, with very high probability, result in * a different message digest, and the signature will fail to verify.

* *

The SHA-1 is designed to have the following properties: it is * computationally infeasible to find a message which corresponds to a given * message digest, or to find two different messages which produce the same * message digest.

* *

References:

* *
    *
  1. SECURE HASH * STANDARD
    * Federal Information, Processing Standards Publication 180-1, 1995 April 17. *
  2. *
* * @version $Revision: 1.9 $ */ public class Sha160 extends BaseHash { // Constants and variables // ------------------------------------------------------------------------- private static final int BLOCK_SIZE = 64; // inner block size in bytes private static final String DIGEST0 = "A9993E364706816ABA3E25717850C26C9CD0D89D"; private static final int[] w = new int[80]; /** caches the result of the correctness test, once executed. */ private static Boolean valid; /** 160-bit interim result. */ private int h0, h1, h2, h3, h4; // Constructor(s) // ------------------------------------------------------------------------- /** Trivial 0-arguments constructor. */ public Sha160() { super(Registry.SHA160_HASH, 20, BLOCK_SIZE); } /** *

Private constructor for cloning purposes.

* * @param md the instance to clone. */ private Sha160(Sha160 md) { this(); this.h0 = md.h0; this.h1 = md.h1; this.h2 = md.h2; this.h3 = md.h3; this.h4 = md.h4; this.count = md.count; this.buffer = (byte[]) md.buffer.clone(); } // Class methods // ------------------------------------------------------------------------- public static final int[] G(int hh0, int hh1, int hh2, int hh3, int hh4, byte[] in, int offset) { // int[] w = new int[80]; // int i, T; // for (i = 0; i < 16; i++) { // w[i] = in[offset++] << 24 | // (in[offset++] & 0xFF) << 16 | // (in[offset++] & 0xFF) << 8 | // (in[offset++] & 0xFF); // } // for (i = 16; i < 80; i++) { // T = w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16]; // w[i] = T << 1 | T >>> 31; // } // return sha(hh0, hh1, hh2, hh3, hh4, in, offset, w); return sha(hh0, hh1, hh2, hh3, hh4, in, offset); } // Instance methods // ------------------------------------------------------------------------- // java.lang.Cloneable interface implementation ---------------------------- public Object clone() { return new Sha160(this); } // Implementation of concrete methods in BaseHash -------------------------- protected void transform(byte[] in, int offset) { // int i, T; // for (i = 0; i < 16; i++) { // W[i] = in[offset++] << 24 | // (in[offset++] & 0xFF) << 16 | // (in[offset++] & 0xFF) << 8 | // (in[offset++] & 0xFF); // } // for (i = 16; i < 80; i++) { // T = W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16]; // W[i] = T << 1 | T >>> 31; // } // int[] result = sha(h0, h1, h2, h3, h4, in, offset, W); int[] result = sha(h0, h1, h2, h3, h4, in, offset); h0 = result[0]; h1 = result[1]; h2 = result[2]; h3 = result[3]; h4 = result[4]; } protected byte[] padBuffer() { int n = (int)(count % BLOCK_SIZE); int padding = (n < 56) ? (56 - n) : (120 - n); byte[] result = new byte[padding + 8]; // padding is always binary 1 followed by binary 0s result[0] = (byte) 0x80; // save number of bits, casting the long to an array of 8 bytes long bits = count << 3; result[padding++] = (byte)(bits >>> 56); result[padding++] = (byte)(bits >>> 48); result[padding++] = (byte)(bits >>> 40); result[padding++] = (byte)(bits >>> 32); result[padding++] = (byte)(bits >>> 24); result[padding++] = (byte)(bits >>> 16); result[padding++] = (byte)(bits >>> 8); result[padding ] = (byte) bits; return result; } protected byte[] getResult() { byte[] result = new byte[] { (byte)(h0 >>> 24), (byte)(h0 >>> 16), (byte)(h0 >>> 8), (byte) h0, (byte)(h1 >>> 24), (byte)(h1 >>> 16), (byte)(h1 >>> 8), (byte) h1, (byte)(h2 >>> 24), (byte)(h2 >>> 16), (byte)(h2 >>> 8), (byte) h2, (byte)(h3 >>> 24), (byte)(h3 >>> 16), (byte)(h3 >>> 8), (byte) h3, (byte)(h4 >>> 24), (byte)(h4 >>> 16), (byte)(h4 >>> 8), (byte) h4 }; return result; } protected void resetContext() { // magic SHA-1/RIPEMD160 initialisation constants h0 = 0x67452301; h1 = 0xEFCDAB89; h2 = 0x98BADCFE; h3 = 0x10325476; h4 = 0xC3D2E1F0; } public boolean selfTest() { if (valid == null) { Sha160 md = new Sha160(); md.update((byte) 0x61); // a md.update((byte) 0x62); // b md.update((byte) 0x63); // c String result = Util.toString(md.digest()); valid = new Boolean(DIGEST0.equals(result)); } return valid.booleanValue(); } // SHA specific methods ---------------------------------------------------- private static final synchronized int[] // sha(int hh0, int hh1, int hh2, int hh3, int hh4, byte[] in, int offset, int[] w) { sha(int hh0, int hh1, int hh2, int hh3, int hh4, byte[] in, int offset) { int A = hh0; int B = hh1; int C = hh2; int D = hh3; int E = hh4; int r, T; for (r = 0; r < 16; r++) { w[r] = in[offset++] << 24 | (in[offset++] & 0xFF) << 16 | (in[offset++] & 0xFF) << 8 | (in[offset++] & 0xFF); } for (r = 16; r < 80; r++) { T = w[r-3] ^ w[r-8] ^ w[r-14] ^ w[r-16]; w[r] = T << 1 | T >>> 31; } // rounds 0-19 for (r = 0; r < 20; r++) { T = (A << 5 | A >>> 27) + ((B & C) | (~B & D)) + E + w[r] + 0x5A827999; E = D; D = C; C = B << 30 | B >>> 2; B = A; A = T; } // rounds 20-39 for (r = 20; r < 40; r++) { T = (A << 5 | A >>> 27) + (B ^ C ^ D) + E + w[r] + 0x6ED9EBA1; E = D; D = C; C = B << 30 | B >>> 2; B = A; A = T; } // rounds 40-59 for (r = 40; r < 60; r++) { T = (A << 5 | A >>> 27) + (B & C | B & D | C & D) + E + w[r] + 0x8F1BBCDC; E = D; D = C; C = B << 30 | B >>> 2; B = A; A = T; } // rounds 60-79 for (r = 60; r < 80; r++) { T = (A << 5 | A >>> 27) + (B ^ C ^ D) + E + w[r] + 0xCA62C1D6; E = D; D = C; C = B << 30 | B >>> 2; B = A; A = T; } return new int[] {hh0+A, hh1+B, hh2+C, hh3+D, hh4+E}; } }




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