md5.java

一个Java例子

               ///* Append length (before padding) */
               md5Update(bits, 8);

               ///* Store state in digest */
               Encode (digest, state, 16);

       }

       /* md5Memcpy是一个内部使用的byte数组的块拷贝函数，从input的inpos开始把len长度的
　　　　　 字节拷贝到output的outpos位置开始
       */

       private void md5Memcpy (byte[] output, byte[] input,
               int outpos, int inpos, int len)
       {
               int i;

               for (i = 0; i < len; i++)
                       output[outpos + i] = input[inpos + i];
       }

       /*
          md5Transform是MD5核心变换程序，有md5Update调用，block是分块的原始字节
       */
       private void md5Transform (byte block[]) {
               long a = state[0], b = state[1], c = state[2], d = state[3];
               long[] x = new long[16];

               Decode (x, block, 64);

               /* Round 1 */
               a = FF (a, b, c, d, x[0], S11, 0xd76aa478L); /* 1 */
               d = FF (d, a, b, c, x[1], S12, 0xe8c7b756L); /* 2 */
               c = FF (c, d, a, b, x[2], S13, 0x242070dbL); /* 3 */
               b = FF (b, c, d, a, x[3], S14, 0xc1bdceeeL); /* 4 */
               a = FF (a, b, c, d, x[4], S11, 0xf57c0fafL); /* 5 */
               d = FF (d, a, b, c, x[5], S12, 0x4787c62aL); /* 6 */
               c = FF (c, d, a, b, x[6], S13, 0xa8304613L); /* 7 */
               b = FF (b, c, d, a, x[7], S14, 0xfd469501L); /* 8 */
               a = FF (a, b, c, d, x[8], S11, 0x698098d8L); /* 9 */
               d = FF (d, a, b, c, x[9], S12, 0x8b44f7afL); /* 10 */
               c = FF (c, d, a, b, x[10], S13, 0xffff5bb1L); /* 11 */
               b = FF (b, c, d, a, x[11], S14, 0x895cd7beL); /* 12 */
               a = FF (a, b, c, d, x[12], S11, 0x6b901122L); /* 13 */
               d = FF (d, a, b, c, x[13], S12, 0xfd987193L); /* 14 */
               c = FF (c, d, a, b, x[14], S13, 0xa679438eL); /* 15 */
               b = FF (b, c, d, a, x[15], S14, 0x49b40821L); /* 16 */

               /* Round 2 */
               a = GG (a, b, c, d, x[1], S21, 0xf61e2562L); /* 17 */
               d = GG (d, a, b, c, x[6], S22, 0xc040b340L); /* 18 */
               c = GG (c, d, a, b, x[11], S23, 0x265e5a51L); /* 19 */
               b = GG (b, c, d, a, x[0], S24, 0xe9b6c7aaL); /* 20 */
               a = GG (a, b, c, d, x[5], S21, 0xd62f105dL); /* 21 */
               d = GG (d, a, b, c, x[10], S22, 0x2441453L); /* 22 */
               c = GG (c, d, a, b, x[15], S23, 0xd8a1e681L); /* 23 */
               b = GG (b, c, d, a, x[4], S24, 0xe7d3fbc8L); /* 24 */
               a = GG (a, b, c, d, x[9], S21, 0x21e1cde6L); /* 25 */
               d = GG (d, a, b, c, x[14], S22, 0xc33707d6L); /* 26 */
               c = GG (c, d, a, b, x[3], S23, 0xf4d50d87L); /* 27 */
               b = GG (b, c, d, a, x[8], S24, 0x455a14edL); /* 28 */
               a = GG (a, b, c, d, x[13], S21, 0xa9e3e905L); /* 29 */
               d = GG (d, a, b, c, x[2], S22, 0xfcefa3f8L); /* 30 */
               c = GG (c, d, a, b, x[7], S23, 0x676f02d9L); /* 31 */
               b = GG (b, c, d, a, x[12], S24, 0x8d2a4c8aL); /* 32 */

               /* Round 3 */
               a = HH (a, b, c, d, x[5], S31, 0xfffa3942L); /* 33 */
               d = HH (d, a, b, c, x[8], S32, 0x8771f681L); /* 34 */
               c = HH (c, d, a, b, x[11], S33, 0x6d9d6122L); /* 35 */
               b = HH (b, c, d, a, x[14], S34, 0xfde5380cL); /* 36 */
               a = HH (a, b, c, d, x[1], S31, 0xa4beea44L); /* 37 */
               d = HH (d, a, b, c, x[4], S32, 0x4bdecfa9L); /* 38 */
               c = HH (c, d, a, b, x[7], S33, 0xf6bb4b60L); /* 39 */
               b = HH (b, c, d, a, x[10], S34, 0xbebfbc70L); /* 40 */
               a = HH (a, b, c, d, x[13], S31, 0x289b7ec6L); /* 41 */
               d = HH (d, a, b, c, x[0], S32, 0xeaa127faL); /* 42 */
               c = HH (c, d, a, b, x[3], S33, 0xd4ef3085L); /* 43 */
               b = HH (b, c, d, a, x[6], S34, 0x4881d05L); /* 44 */
               a = HH (a, b, c, d, x[9], S31, 0xd9d4d039L); /* 45 */
               d = HH (d, a, b, c, x[12], S32, 0xe6db99e5L); /* 46 */
               c = HH (c, d, a, b, x[15], S33, 0x1fa27cf8L); /* 47 */
               b = HH (b, c, d, a, x[2], S34, 0xc4ac5665L); /* 48 */

               /* Round 4 */
               a = II (a, b, c, d, x[0], S41, 0xf4292244L); /* 49 */
               d = II (d, a, b, c, x[7], S42, 0x432aff97L); /* 50 */
               c = II (c, d, a, b, x[14], S43, 0xab9423a7L); /* 51 */
               b = II (b, c, d, a, x[5], S44, 0xfc93a039L); /* 52 */
               a = II (a, b, c, d, x[12], S41, 0x655b59c3L); /* 53 */
               d = II (d, a, b, c, x[3], S42, 0x8f0ccc92L); /* 54 */
               c = II (c, d, a, b, x[10], S43, 0xffeff47dL); /* 55 */
               b = II (b, c, d, a, x[1], S44, 0x85845dd1L); /* 56 */
               a = II (a, b, c, d, x[8], S41, 0x6fa87e4fL); /* 57 */
               d = II (d, a, b, c, x[15], S42, 0xfe2ce6e0L); /* 58 */
               c = II (c, d, a, b, x[6], S43, 0xa3014314L); /* 59 */
               b = II (b, c, d, a, x[13], S44, 0x4e0811a1L); /* 60 */
               a = II (a, b, c, d, x[4], S41, 0xf7537e82L); /* 61 */
               d = II (d, a, b, c, x[11], S42, 0xbd3af235L); /* 62 */
               c = II (c, d, a, b, x[2], S43, 0x2ad7d2bbL); /* 63 */
               b = II (b, c, d, a, x[9], S44, 0xeb86d391L); /* 64 */

               state[0] += a;
               state[1] += b;
               state[2] += c;
               state[3] += d;

       }

       /*Encode把long数组按顺序拆成byte数组，因为java的long类型是64bit的，
         只拆低32bit，以适应原始C实现的用途
       */
       private void Encode (byte[] output, long[] input, int len) {
               int i, j;

               for (i = 0, j = 0; j < len; i++, j += 4) {
                       output[j] = (byte)(input[i] & 0xffL);
                       output[j + 1] = (byte)((input[i] >>> 8) & 0xffL);
                       output[j + 2] = (byte)((input[i] >>> 16) & 0xffL);
                       output[j + 3] = (byte)((input[i] >>> 24) & 0xffL);
               }
       }

       /*Decode把byte数组按顺序合成成long数组，因为java的long类型是64bit的，
         只合成低32bit，高32bit清零，以适应原始C实现的用途
       */
       private void Decode (long[] output, byte[] input, int len) {
               int i, j;


               for (i = 0, j = 0; j < len; i++, j += 4)
                       output[i] = b2iu(input[j]) |
                               (b2iu(input[j + 1]) << 8) |
                               (b2iu(input[j + 2]) << 16) |
                               (b2iu(input[j + 3]) << 24);

               return;
       }

       /*
         b2iu是我写的一个把byte按照不考虑正负号的原则的＂升位＂程序，因为java没有unsigned运算
       */
       public static long b2iu(byte b) {
               return b < 0 ? b & 0x7F + 128 : b;
       }

/*byteHEX()，用来把一个byte类型的数转换成十六进制的ASCII表示，
　因为java中的byte的toString无法实现这一点，我们又没有C语言中的
 sprintf(outbuf,"%02X",ib)
*/
       public static String byteHEX(byte ib) {
               char[] Digit = { '0','1','2','3','4','5','6','7','8','9',
               'A','B','C','D','E','F' };
               char [] ob = new char[2];
               ob[0] = Digit[(ib >>> 4) & 0X0F];
               ob[1] = Digit[ib & 0X0F];
               String s = new String(ob);
               return s;
       }

       public String toMD5(String source){
         return this.getMD5ofStr(source);
       }

       public static void main(String args[]) {


               MD5 m = new MD5();
               if (Array.getLength(args) == 0) {   //如果没有参数，执行标准的Test Suite

                      System.out.println("MD5 Test suite:");
               System.out.println("MD5(\"\"):"+m.getMD5ofStr(""));
               System.out.println("MD5(\"a\"):"+m.getMD5ofStr("a"));
               System.out.println("MD5(\"\"):"+m.getMD5ofStr("").length());
               System.out.println("MD5(\"a\"):"+m.getMD5ofStr("a").length());

               System.out.println("MD5(\"abc\"):"+m.getMD5ofStr("abc"));
               System.out.println("MD5(\"message digest\"):"+m.getMD5ofStr("message digest"));
               System.out.println("MD5(\"abcdefghijklmnopqrstuvwxyz\"):"+
                       m.getMD5ofStr("abcdefghijklmnopqrstuvwxyz"));
               System.out.println("MD5(\"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789\"):"+
                    m.getMD5ofStr("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"));
               }
               else
                     System.out.println("MD5(" + args[0] + ")=" + m.getMD5ofStr(args[0]));


       }

}