md5.java

一个国人编写的md5编码小程序

public class MD5 
{ 
  /* 
   * A Java implementation of the RSA Data Security, Inc. MD5 Message 
   * Digest Algorithm, as defined in RFC 1321. 
   * Based on the JavaScript implementation of Paul Johnston 
   *      Copyright (C) Paul Johnston 1999 - 2000. 
   *      See http://pajhome.org.uk/site/legal.html for details. 
   * Java Version by Thomas Weber (Orange Interactive GmbH) 
   */ 
   
  /* 
   * Convert a 32-bit number to a hex string with ls-byte first 
   */ 
  String hex_chr = "0123456789abcdef"; 
  private String rhex(int num) 
  { 
    String str = ""; 
    for(int j = 0; j <= 3; j++) 
      str = str + hex_chr.charAt((num >;>; (j * 8 + 4)) &amp; 0x0F) + hex_chr.charAt((num >;>; (j * 8)) &amp; 0x0F); 
    return str; 
  } 
   
  /* 
   * Convert a string to a sequence of 16-word blocks, stored as an array. 
   * Append padding bits and the length, as described in the MD5 standard. 
   */ 
  private int[] str2blks_MD5(String str) 
  { 
    int nblk = ((str.length() + 8) >;>; 6) + 1; 
    int[] blks = new int[nblk * 16]; 
    int i = 0; 
    for(i = 0; i < nblk * 16; i++) { 
      blks = 0; 
    } 
    for(i = 0; i < str.length(); i++) { 
      blks[i >;>; 2] |= str.charAt(i) << ((i % 4) * 8); 
    } 
    blks[i >;>; 2] |= 0x80 << ((i % 4) * 8); 
    blks[nblk * 16 - 2] = str.length()*8; 
       
    return blks; 
  } 
   
  /* 
   * Add integers, wrapping at 2^32 
   */ 
  private int add(int x, int y) 
  { 
    return ((x&amp;0x7FFFFFFF) + (y&amp;0x7FFFFFFF)) ^ (x&amp;0x80000000) ^ (y&amp;0x80000000); 
  } 
   
  /* 
   * Bitwise rotate a 32-bit number to the left 
   */ 
  private int rol(int num, int cnt) 
  { 
    return (num << cnt) | (num >;>;>; (32 - cnt)); 
  } 
   
  /* 
   * These functions implement the basic operation for each round of the 
   * algorithm. 
   */ 
  private int cmn(int q, int a, int b, int x, int s, int t) 
  { 
    return add(rol(add(add(a, q), add(x, t)), s), b); 
  } 
  private int ff(int a, int b, int c, int d, int x, int s, int t) 
  { 
    return cmn((b &amp; c) | ((~b) &amp; d), a, b, x, s, t); 
  } 
  private int gg(int a, int b, int c, int d, int x, int s, int t) 
  { 
    return cmn((b &amp; d) | (c &amp; (~d)), a, b, x, s, t); 
  } 
  private int hh(int a, int b, int c, int d, int x, int s, int t) 
  { 
    return cmn(b ^ c ^ d, a, b, x, s, t); 
  } 
  private int ii(int a, int b, int c, int d, int x, int s, int t) 
  { 
    return cmn(c ^ (b | (~d)), a, b, x, s, t); 
  } 
   
  /* 
   * Take a string and return the hex representation of its MD5. 
   */ 
  public String calcMD5(String str) 
  { 
    int[] x = str2blks_MD5(str); 
    int a = 0x67452301; 
    int b = 0xEFCDAB89; 
    int c = 0x98BADCFE; 
    int d = 0x10325476; 
   
    for(int i = 0; i < x.length; i += 16) 
    { 
      int olda = a; 
      int oldb = b; 
      int oldc = c; 
      int oldd = d; 
   
      a = ff(a, b, c, d, x[i+ 0], 7 , 0xD76AA478); 
      d = ff(d, a, b, c, x[i+ 1], 12, 0xE8C7B756); 
      c = ff(c, d, a, b, x[i+ 2], 17, 0x242070DB); 
      b = ff(b, c, d, a, x[i+ 3], 22, 0xC1BDCEEE); 
      a = ff(a, b, c, d, x[i+ 4], 7 , 0xF57C0FAF); 
      d = ff(d, a, b, c, x[i+ 5], 12, 0x4787C62A); 
      c = ff(c, d, a, b, x[i+ 6], 17, 0xA8304613); 
      b = ff(b, c, d, a, x[i+ 7], 22, 0xFD469501); 
      a = ff(a, b, c, d, x[i+ 8], 7 , 0x698098D8); 
      d = ff(d, a, b, c, x[i+ 9], 12, 0x8B44F7AF); 
      c = ff(c, d, a, b, x[i+10], 17, 0xFFFF5BB1); 
      b = ff(b, c, d, a, x[i+11], 22, 0x895CD7BE); 
      a = ff(a, b, c, d, x[i+12], 7 , 0x6B901122); 
      d = ff(d, a, b, c, x[i+13], 12, 0xFD987193); 
      c = ff(c, d, a, b, x[i+14], 17, 0xA679438E); 
      b = ff(b, c, d, a, x[i+15], 22, 0x49B40821); 
   
      a = gg(a, b, c, d, x[i+ 1], 5 , 0xF61E2562); 
      d = gg(d, a, b, c, x[i+ 6], 9 , 0xC040B340); 
      c = gg(c, d, a, b, x[i+11], 14, 0x265E5A51); 
      b = gg(b, c, d, a, x[i+ 0], 20, 0xE9B6C7AA); 
      a = gg(a, b, c, d, x[i+ 5], 5 , 0xD62F105D); 
      d = gg(d, a, b, c, x[i+10], 9 , 0x02441453); 
      c = gg(c, d, a, b, x[i+15], 14, 0xD8A1E681); 
      b = gg(b, c, d, a, x[i+ 4], 20, 0xE7D3FBC8); 
      a = gg(a, b, c, d, x[i+ 9], 5 , 0x21E1CDE6); 
      d = gg(d, a, b, c, x[i+14], 9 , 0xC33707D6); 
      c = gg(c, d, a, b, x[i+ 3], 14, 0xF4D50D87); 
      b = gg(b, c, d, a, x[i+ 8], 20, 0x455A14ED); 
      a = gg(a, b, c, d, x[i+13], 5 , 0xA9E3E905); 
      d = gg(d, a, b, c, x[i+ 2], 9 , 0xFCEFA3F8); 
      c = gg(c, d, a, b, x[i+ 7], 14, 0x676F02D9); 
      b = gg(b, c, d, a, x[i+12], 20, 0x8D2A4C8A); 
   
      a = hh(a, b, c, d, x[i+ 5], 4 , 0xFFFA3942); 
      d = hh(d, a, b, c, x[i+ 8], 11, 0x8771F681); 
      c = hh(c, d, a, b, x[i+11], 16, 0x6D9D6122); 
      b = hh(b, c, d, a, x[i+14], 23, 0xFDE5380C); 
      a = hh(a, b, c, d, x[i+ 1], 4 , 0xA4BEEA44); 
      d = hh(d, a, b, c, x[i+ 4], 11, 0x4BDECFA9); 
      c = hh(c, d, a, b, x[i+ 7], 16, 0xF6BB4B60); 
      b = hh(b, c, d, a, x[i+10], 23, 0xBEBFBC70); 
      a = hh(a, b, c, d, x[i+13], 4 , 0x289B7EC6); 
      d = hh(d, a, b, c, x[i+ 0], 11, 0xEAA127FA); 
      c = hh(c, d, a, b, x[i+ 3], 16, 0xD4EF3085); 
      b = hh(b, c, d, a, x[i+ 6], 23, 0x04881D05); 
      a = hh(a, b, c, d, x[i+ 9], 4 , 0xD9D4D039); 
      d = hh(d, a, b, c, x[i+12], 11, 0xE6DB99E5); 
      c = hh(c, d, a, b, x[i+15], 16, 0x1FA27CF8); 
      b = hh(b, c, d, a, x[i+ 2], 23, 0xC4AC5665); 
   
      a = ii(a, b, c, d, x[i+ 0], 6 , 0xF4292244); 
      d = ii(d, a, b, c, x[i+ 7], 10, 0x432AFF97); 
      c = ii(c, d, a, b, x[i+14], 15, 0xAB9423A7); 
      b = ii(b, c, d, a, x[i+ 5], 21, 0xFC93A039); 
      a = ii(a, b, c, d, x[i+12], 6 , 0x655B59C3); 
      d = ii(d, a, b, c, x[i+ 3], 10, 0x8F0CCC92); 
      c = ii(c, d, a, b, x[i+10], 15, 0xFFEFF47D); 
      b = ii(b, c, d, a, x[i+ 1], 21, 0x85845DD1); 
      a = ii(a, b, c, d, x[i+ 8], 6 , 0x6FA87E4F); 
      d = ii(d, a, b, c, x[i+15], 10, 0xFE2CE6E0); 
      c = ii(c, d, a, b, x[i+ 6], 15, 0xA3014314); 
      b = ii(b, c, d, a, x[i+13], 21, 0x4E0811A1); 
      a = ii(a, b, c, d, x[i+ 4], 6 , 0xF7537E82); 
      d = ii(d, a, b, c, x[i+11], 10, 0xBD3AF235); 
      c = ii(c, d, a, b, x[i+ 2], 15, 0x2AD7D2BB); 
      b = ii(b, c, d, a, x[i+ 9], 21, 0xEB86D391); 
   
      a = add(a, olda); 
      b = add(b, oldb); 
      c = add(c, oldc); 
      d = add(d, oldd); 
    } 
    return rhex(a) + rhex(b) + rhex(c) + rhex(d); 
  } 

}