md5digest.java

这是linux下ssl vpn的实现程序

/*
 *  SSL-Explorer
 *
 *  Copyright (C) 2003-2006 3SP LTD. All Rights Reserved
 *
 *  This program 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 of
 *  the License, or (at your option) any later version.
 *  This program 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; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
			
package com.maverick.crypto.digests;

/**
 * implementation of MD5 as outlined in "Handbook of Applied Cryptography", pages 346 - 347.
 */
public class MD5Digest
    extends GeneralDigest {
  private static final int DIGEST_LENGTH = 16;

  private int H1, H2, H3, H4; // IV's

  private int[] X = new int[16];
  private int xOff;

  /**
   * Standard constructor
   */
  public MD5Digest() {
    reset();
  }

  /**
   * Copy constructor.  This will copy the state of the provided
   * message digest.
   */
  public MD5Digest(MD5Digest t) {
    super(t);

    H1 = t.H1;
    H2 = t.H2;
    H3 = t.H3;
    H4 = t.H4;

    System.arraycopy(t.X, 0, X, 0, t.X.length);
    xOff = t.xOff;
  }

  public String getAlgorithmName() {
    return "MD5";
  }

  public int getDigestSize() {
    return DIGEST_LENGTH;
  }

  protected void processWord(
      byte[] in,
      int inOff) {
    X[xOff++] = (in[inOff] & 0xff) | ( (in[inOff + 1] & 0xff) << 8)
        | ( (in[inOff + 2] & 0xff) << 16) | ( (in[inOff + 3] & 0xff) << 24);

    if (xOff == 16) {
      processBlock();
    }
  }

  protected void processLength(
      long bitLength) {
    if (xOff > 14) {
      processBlock();
    }

    X[14] = (int) (bitLength & 0xffffffff);
    X[15] = (int) (bitLength >>> 32);
  }

  private void unpackWord(
      int word,
      byte[] out,
      int outOff) {
    out[outOff] = (byte) word;
    out[outOff + 1] = (byte) (word >>> 8);
    out[outOff + 2] = (byte) (word >>> 16);
    out[outOff + 3] = (byte) (word >>> 24);
  }

  public int doFinal(
      byte[] out,
      int outOff) {
    finish();

    unpackWord(H1, out, outOff);
    unpackWord(H2, out, outOff + 4);
    unpackWord(H3, out, outOff + 8);
    unpackWord(H4, out, outOff + 12);

    reset();

    return DIGEST_LENGTH;
  }

  /**
   * reset the chaining variables to the IV values.
   */
  public void reset() {
    super.reset();

    H1 = 0x67452301;
    H2 = 0xefcdab89;
    H3 = 0x98badcfe;
    H4 = 0x10325476;

    xOff = 0;

    for (int i = 0; i != X.length; i++) {
      X[i] = 0;
    }
  }

  //
  // round 1 left rotates
  //
  private static final int S11 = 7;
  private static final int S12 = 12;
  private static final int S13 = 17;
  private static final int S14 = 22;

  //
  // round 2 left rotates
  //
  private static final int S21 = 5;
  private static final int S22 = 9;
  private static final int S23 = 14;
  private static final int S24 = 20;

  //
  // round 3 left rotates
  //
  private static final int S31 = 4;
  private static final int S32 = 11;
  private static final int S33 = 16;
  private static final int S34 = 23;

  //
  // round 4 left rotates
  //
  private static final int S41 = 6;
  private static final int S42 = 10;
  private static final int S43 = 15;
  private static final int S44 = 21;

  /*
   * rotate int x left n bits.
   */
  private int rotateLeft(
      int x,
      int n) {
    return (x << n) | (x >>> (32 - n));
  }

  /*
   * F, G, H and I are the basic MD5 functions.
   */
  private int F(
      int u,
      int v,
      int w) {
    return (u & v) | (~u & w);
  }

  private int G(
      int u,
      int v,
      int w) {
    return (u & w) | (v & ~w);
  }

  private int H(
      int u,
      int v,
      int w) {
    return u ^ v ^ w;
  }

  private int K(
      int u,
      int v,
      int w) {
    return v ^ (u | ~w);
  }

  protected void processBlock() {
    int a = H1;
    int b = H2;
    int c = H3;
    int d = H4;

    //
    // Round 1 - F cycle, 16 times.
    //
    a = rotateLeft( (a + F(b, c, d) + X[0] + 0xd76aa478), S11) + b;
    d = rotateLeft( (d + F(a, b, c) + X[1] + 0xe8c7b756), S12) + a;
    c = rotateLeft( (c + F(d, a, b) + X[2] + 0x242070db), S13) + d;
    b = rotateLeft( (b + F(c, d, a) + X[3] + 0xc1bdceee), S14) + c;
    a = rotateLeft( (a + F(b, c, d) + X[4] + 0xf57c0faf), S11) + b;
    d = rotateLeft( (d + F(a, b, c) + X[5] + 0x4787c62a), S12) + a;
    c = rotateLeft( (c + F(d, a, b) + X[6] + 0xa8304613), S13) + d;
    b = rotateLeft( (b + F(c, d, a) + X[7] + 0xfd469501), S14) + c;
    a = rotateLeft( (a + F(b, c, d) + X[8] + 0x698098d8), S11) + b;
    d = rotateLeft( (d + F(a, b, c) + X[9] + 0x8b44f7af), S12) + a;
    c = rotateLeft( (c + F(d, a, b) + X[10] + 0xffff5bb1), S13) + d;
    b = rotateLeft( (b + F(c, d, a) + X[11] + 0x895cd7be), S14) + c;
    a = rotateLeft( (a + F(b, c, d) + X[12] + 0x6b901122), S11) + b;
    d = rotateLeft( (d + F(a, b, c) + X[13] + 0xfd987193), S12) + a;
    c = rotateLeft( (c + F(d, a, b) + X[14] + 0xa679438e), S13) + d;
    b = rotateLeft( (b + F(c, d, a) + X[15] + 0x49b40821), S14) + c;

    //
    // Round 2 - G cycle, 16 times.
    //
    a = rotateLeft( (a + G(b, c, d) + X[1] + 0xf61e2562), S21) + b;
    d = rotateLeft( (d + G(a, b, c) + X[6] + 0xc040b340), S22) + a;
    c = rotateLeft( (c + G(d, a, b) + X[11] + 0x265e5a51), S23) + d;
    b = rotateLeft( (b + G(c, d, a) + X[0] + 0xe9b6c7aa), S24) + c;
    a = rotateLeft( (a + G(b, c, d) + X[5] + 0xd62f105d), S21) + b;
    d = rotateLeft( (d + G(a, b, c) + X[10] + 0x02441453), S22) + a;
    c = rotateLeft( (c + G(d, a, b) + X[15] + 0xd8a1e681), S23) + d;
    b = rotateLeft( (b + G(c, d, a) + X[4] + 0xe7d3fbc8), S24) + c;
    a = rotateLeft( (a + G(b, c, d) + X[9] + 0x21e1cde6), S21) + b;
    d = rotateLeft( (d + G(a, b, c) + X[14] + 0xc33707d6), S22) + a;
    c = rotateLeft( (c + G(d, a, b) + X[3] + 0xf4d50d87), S23) + d;
    b = rotateLeft( (b + G(c, d, a) + X[8] + 0x455a14ed), S24) + c;
    a = rotateLeft( (a + G(b, c, d) + X[13] + 0xa9e3e905), S21) + b;
    d = rotateLeft( (d + G(a, b, c) + X[2] + 0xfcefa3f8), S22) + a;
    c = rotateLeft( (c + G(d, a, b) + X[7] + 0x676f02d9), S23) + d;
    b = rotateLeft( (b + G(c, d, a) + X[12] + 0x8d2a4c8a), S24) + c;

    //
    // Round 3 - H cycle, 16 times.
    //
    a = rotateLeft( (a + H(b, c, d) + X[5] + 0xfffa3942), S31) + b;
    d = rotateLeft( (d + H(a, b, c) + X[8] + 0x8771f681), S32) + a;
    c = rotateLeft( (c + H(d, a, b) + X[11] + 0x6d9d6122), S33) + d;
    b = rotateLeft( (b + H(c, d, a) + X[14] + 0xfde5380c), S34) + c;
    a = rotateLeft( (a + H(b, c, d) + X[1] + 0xa4beea44), S31) + b;
    d = rotateLeft( (d + H(a, b, c) + X[4] + 0x4bdecfa9), S32) + a;
    c = rotateLeft( (c + H(d, a, b) + X[7] + 0xf6bb4b60), S33) + d;
    b = rotateLeft( (b + H(c, d, a) + X[10] + 0xbebfbc70), S34) + c;
    a = rotateLeft( (a + H(b, c, d) + X[13] + 0x289b7ec6), S31) + b;
    d = rotateLeft( (d + H(a, b, c) + X[0] + 0xeaa127fa), S32) + a;
    c = rotateLeft( (c + H(d, a, b) + X[3] + 0xd4ef3085), S33) + d;
    b = rotateLeft( (b + H(c, d, a) + X[6] + 0x04881d05), S34) + c;
    a = rotateLeft( (a + H(b, c, d) + X[9] + 0xd9d4d039), S31) + b;
    d = rotateLeft( (d + H(a, b, c) + X[12] + 0xe6db99e5), S32) + a;
    c = rotateLeft( (c + H(d, a, b) + X[15] + 0x1fa27cf8), S33) + d;
    b = rotateLeft( (b + H(c, d, a) + X[2] + 0xc4ac5665), S34) + c;

    //
    // Round 4 - K cycle, 16 times.
    //
    a = rotateLeft( (a + K(b, c, d) + X[0] + 0xf4292244), S41) + b;
    d = rotateLeft( (d + K(a, b, c) + X[7] + 0x432aff97), S42) + a;
    c = rotateLeft( (c + K(d, a, b) + X[14] + 0xab9423a7), S43) + d;
    b = rotateLeft( (b + K(c, d, a) + X[5] + 0xfc93a039), S44) + c;
    a = rotateLeft( (a + K(b, c, d) + X[12] + 0x655b59c3), S41) + b;
    d = rotateLeft( (d + K(a, b, c) + X[3] + 0x8f0ccc92), S42) + a;
    c = rotateLeft( (c + K(d, a, b) + X[10] + 0xffeff47d), S43) + d;
    b = rotateLeft( (b + K(c, d, a) + X[1] + 0x85845dd1), S44) + c;
    a = rotateLeft( (a + K(b, c, d) + X[8] + 0x6fa87e4f), S41) + b;
    d = rotateLeft( (d + K(a, b, c) + X[15] + 0xfe2ce6e0), S42) + a;
    c = rotateLeft( (c + K(d, a, b) + X[6] + 0xa3014314), S43) + d;
    b = rotateLeft( (b + K(c, d, a) + X[13] + 0x4e0811a1), S44) + c;
    a = rotateLeft( (a + K(b, c, d) + X[4] + 0xf7537e82), S41) + b;
    d = rotateLeft( (d + K(a, b, c) + X[11] + 0xbd3af235), S42) + a;
    c = rotateLeft( (c + K(d, a, b) + X[2] + 0x2ad7d2bb), S43) + d;
    b = rotateLeft( (b + K(c, d, a) + X[9] + 0xeb86d391), S44) + c;

    H1 += a;
    H2 += b;
    H3 += c;
    H4 += d;

    //
    // reset the offset and clean out the word buffer.
    //
    xOff = 0;
    for (int i = 0; i != X.length; i++) {
      X[i] = 0;
    }
  }
}