md5.java

这个是网络上下载的一个struct框架的程序

/***
* jwma Java WebMail
* Copyright (c) 2000-2003 jwma team
*
* jwma is free software; you can distribute and use this source
* under the terms of the BSD-style license received along with
* the distribution.
 ***/
package com.struts2.framework.util;

/**
 * This class implements the MD5 algorithm.
 * <p>
 * The specification is available from RFC 1321,
 * and there are numerous implementations out there,
 * this one was tuned specifically for hashing short
 * strings (i.e. passwords).
 * <p>
 * I do not recommend to use this implementation for
 * anything else but that, and if anybody feels that
 * this code is to "close" to something available on
 * the net, please contact me, and I will certainly take
 * steps to clear up the situation.
 */
public final class MD5 {

  /**
   * Returns the MD5 hash digest transformed into a hex
   * representation as <tt>String</tt>.
   *
   * @return the MD5 hash of the input as <tt>String</tt>.
   */
  public static final String hash(String str) {
    return MD5.asHex(MD5.digest(str.getBytes()));
  }//hash

  /**
   * Returns the MD5 hash of the input data.
   * <p>
   * Following the the MD5 standard specification, the result
   * is returned least significant byte first, however,
   * many applications use the most significant byte first (more conventional).
   *
   * @param msg the <tt>byte[]</tt> to be digested.
   *
   * @return the MD5 hash of the data as <tt>String</tt>.
   */
  public static final byte[] digest(byte[] msg) {
    int padsize = (120 - (msg.length % 64)) % 64;
    int i;
    long l = msg.length * 8;

    //MD5 registers
    int a = 0x67452301, aa,
        b = 0xefcdab89, bb,
        c = 0x98badcfe, cc,
        d = 0x10325476, dd;

    byte[] src = new byte[msg.length + padsize + 8];

    //padding
    try {
      System.arraycopy(msg, 0, src, 0, msg.length);
    } catch (Exception ex) {
      //should not happen, but calm's the compiler
    }

    src[msg.length] = (byte) 0x80;

    for (i = msg.length + 1; i < msg.length + padsize; i++) src[i] = 0;

    //append length
    for (i = src.length - 8; i < src.length; i++) {
      src[i] = (byte) l;
      l >>>= 8;
    }
    int[] x = new int[16];

    //prcess the data 16-word blocks
    for (i = 0; i < src.length; i += 64) {
      //construct block
      for (int j = 0; j < 16; j++) {
        x[j] = 0;
        for (int k = 3; k >= 0; k--) {
          x[j] <<= 8;
          x[j] += src[i + j * 4 + k] & 0xff;
        }
      }
      aa = a;
      bb = b;
      cc = c;
      dd = d;
      a = round1(a, b, c, d, 0, 7, 1, x);
      d = round1(d, a, b, c, 1, 12, 2, x);
      c = round1(c, d, a, b, 2, 17, 3, x);
      b = round1(b, c, d, a, 3, 22, 4, x);

      a = round1(a, b, c, d, 4, 7, 5, x);
      d = round1(d, a, b, c, 5, 12, 6, x);
      c = round1(c, d, a, b, 6, 17, 7, x);
      b = round1(b, c, d, a, 7, 22, 8, x);

      a = round1(a, b, c, d, 8, 7, 9, x);
      d = round1(d, a, b, c, 9, 12, 10, x);
      c = round1(c, d, a, b, 10, 17, 11, x);
      b = round1(b, c, d, a, 11, 22, 12, x);

      a = round1(a, b, c, d, 12, 7, 13, x);
      d = round1(d, a, b, c, 13, 12, 14, x);
      c = round1(c, d, a, b, 14, 17, 15, x);
      b = round1(b, c, d, a, 15, 22, 16, x);

      a = round2(a, b, c, d, 1, 5, 17, x);
      d = round2(d, a, b, c, 6, 9, 18, x);
      c = round2(c, d, a, b, 11, 14, 19, x);
      b = round2(b, c, d, a, 0, 20, 20, x);

      a = round2(a, b, c, d, 5, 5, 21, x);
      d = round2(d, a, b, c, 10, 9, 22, x);
      c = round2(c, d, a, b, 15, 14, 23, x);
      b = round2(b, c, d, a, 4, 20, 24, x);

      a = round2(a, b, c, d, 9, 5, 25, x);
      d = round2(d, a, b, c, 14, 9, 26, x);
      c = round2(c, d, a, b, 3, 14, 27, x);
      b = round2(b, c, d, a, 8, 20, 28, x);

      a = round2(a, b, c, d, 13, 5, 29, x);
      d = round2(d, a, b, c, 2, 9, 30, x);
      c = round2(c, d, a, b, 7, 14, 31, x);
      b = round2(b, c, d, a, 12, 20, 32, x);

      a = round3(a, b, c, d, 5, 4, 33, x);
      d = round3(d, a, b, c, 8, 11, 34, x);
      c = round3(c, d, a, b, 11, 16, 35, x);
      b = round3(b, c, d, a, 14, 23, 36, x);

      a = round3(a, b, c, d, 1, 4, 37, x);
      d = round3(d, a, b, c, 4, 11, 38, x);
      c = round3(c, d, a, b, 7, 16, 39, x);
      b = round3(b, c, d, a, 10, 23, 40, x);

      a = round3(a, b, c, d, 13, 4, 41, x);
      d = round3(d, a, b, c, 0, 11, 42, x);
      c = round3(c, d, a, b, 3, 16, 43, x);
      b = round3(b, c, d, a, 6, 23, 44, x);

      a = round3(a, b, c, d, 9, 4, 45, x);
      d = round3(d, a, b, c, 12, 11, 46, x);
      c = round3(c, d, a, b, 15, 16, 47, x);
      b = round3(b, c, d, a, 2, 23, 48, x);

      a = round4(a, b, c, d, 0, 6, 49, x);
      d = round4(d, a, b, c, 7, 10, 50, x);
      c = round4(c, d, a, b, 14, 15, 51, x);
      b = round4(b, c, d, a, 5, 21, 52, x);

      a = round4(a, b, c, d, 12, 6, 53, x);
      d = round4(d, a, b, c, 3, 10, 54, x);
      c = round4(c, d, a, b, 10, 15, 55, x);
      b = round4(b, c, d, a, 1, 21, 56, x);

      a = round4(a, b, c, d, 8, 6, 57, x);
      d = round4(d, a, b, c, 15, 10, 58, x);
      c = round4(c, d, a, b, 6, 15, 59, x);
      b = round4(b, c, d, a, 13, 21, 60, x);

      a = round4(a, b, c, d, 4, 6, 61, x);
      d = round4(d, a, b, c, 11, 10, 62, x);
      c = round4(c, d, a, b, 2, 15, 63, x);
      b = round4(b, c, d, a, 9, 21, 64, x);

      a += aa;
      b += bb;
      c += cc;
      d += dd;
    }
    byte[] ret = new byte[16];

    for (i = 0; i < 4; i++) {
      ret[i] = (byte) a;
      a >>>= 8;
    }
    for (; i < 8; i++) {
      ret[i] = (byte) b;
      b >>>= 8;
    }
    for (; i < 12; i++) {
      ret[i] = (byte) c;
      c >>>= 8;
    }
    for (; i < 16; i++) {
      ret[i] = (byte) d;
      d >>>= 8;
    }
    return ret;
  }//digest


  /** MD5 Transformation routines *********************************************/

  private static final int rot(int x, int s) {
    return x << s | x >>> (32 - s);
  }//rot

  private static final int F(int x, int y, int z) {
    return (x & y) | (~x & z);
  }//F

  private static final int G(int x, int y, int z) {
    return (x & z) | (y & ~z);
  }//G

  private static final int H(int x, int y, int z) {
    return x ^ y ^ z;
  }//H

  private static final int I(int x, int y, int z) {
    return y ^ (x | ~z);
  }//I

  private static final int round1(int a, int b, int c,
                                  int d, int k, int s,
                                  int i, int[] x) {
    return b + rot((a + F(b, c, d) + x[k] + T[i - 1]), s);
  }//round1

  private static final int round2(int a, int b, int c,
                                  int d, int k, int s,
                                  int i, int[] x) {
    return b + rot((a + G(b, c, d) + x[k] + T[i - 1]), s);
  }//round2

  private static final int round3(int a, int b, int c,
                                  int d, int k, int s,
                                  int i, int[] x) {
    return b + rot((a + H(b, c, d) + x[k] + T[i - 1]), s);
  }//round3

  private static final int round4(int a, int b, int c,
                                  int d, int k, int s,
                                  int i, int[] x) {
    return b + rot((a + I(b, c, d) + x[k] + T[i - 1]), s);
  }//round4

  private static final int T[] = {
    0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf,
    0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af,
    0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e,
    0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
    0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6,
    0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8,
    0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122,
    0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
    0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039,
    0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244, 0x432aff97,
    0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d,
    0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
    0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
  };

  /** END MD5 Transformation routines *****************************************/

  /**
   * Returns a <tt>String</tt> containing unsigned hexadecimal
   * numbers as digits.
   * <p>
   * Contains two hex digit characters for each byte from the passed in
   * <tt>byte[]</tt>.
   *
   * @param data the array of bytes to be converted into a hex-string.
   * @return	the generated hexadecimal representation as
   *          <tt>String</tt>.
   */
  public static final String asHex(byte[] data) {
    //double size, two bytes (hex range) for one byte
    StringBuffer buf = new StringBuffer(data.length * 2);
    for (int i = 0; i < data.length; i++) {
      //don't forget the second hex digit
      if (((int) data[i] & 0xff) < 0x10) {
        buf.append("0");
      }
      buf.append(Long.toString((int) data[i] & 0xff, 16));
    }
    return buf.toString();
  }//asHex

  /**
   * A main, to allow using this class from the command line.
   */
  public static void main(String[] args) {
    try {
      if (args == null || args.length == 0) {
        System.out.println("Usage: java com.imb.util.MD5 <password>");
      }
      System.out.println("Hash=" + hash(args[0]));
    } catch (Exception ex) {
      ex.printStackTrace();
    }
  }//main

}//class MD5