md5.java

这个原程序主要是实现中国移动通信互联网短信网关接口协议（cmpp）,他是用java实现的

package com.hoten.cmpp.util;
/************************************************
MD5 算法的Java Bean
@author:Topcat Tuppin
Last Modified:10,Mar,2001
*************************************************/
import java.lang.reflect.*;
/*************************************************
md5 类实现了RSA Data Security, Inc.在提交给IETF
的RFC1321中的MD5 message-digest 算法。
*************************************************/

public class MD5 {
    /* 下面这些S11-S44实际上是一个4*4的矩阵，在原始的C实现中是用#define 实现的，
    这里把它们实现成为static final是表示了只读，切能在同一个进程空间内的多个
    Instance间共享*/
        static final int S11 = 7;
        static final int S12 = 12;
        static final int S13 = 17;
        static final int S14 = 22;

        static final int S21 = 5;
        static final int S22 = 9;
        static final int S23 = 14;
        static final int S24 = 20;

        static final int S31 = 4;
        static final int S32 = 11;
        static final int S33 = 16;
        static final int S34 = 23;

        static final int S41 = 6;
        static final int S42 = 10;
        static final int S43 = 15;
        static final int S44 = 21;

        static final byte[] PADDING = { -128, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        /* 下面的三个成员是MD5计算过程中用到的3个核心数据，在原始的C实现中
           被定义到MD5_CTX结构中

         */
        private long[] state = new long[4];  // state (ABCD)
        private long[] count = new long[2];  // number of bits, modulo 2^64 (lsb first)
        private byte[] buffer = new byte[64]; // input buffer

    /* digestHexStr是MD5的唯一一个公共成员，是最新一次计算结果的
    　 16进制ASCII表示.
    */
        public String digestHexStr;

        /* digest,是最新一次计算结果的2进制内部表示，表示128bit的MD5值.
    */
        private byte[] digest = new byte[16];

    /*
      getMD5ofStr是类MD5最主要的公共方法，入口参数是你想要进行MD5变换的字符串
      返回的是变换完的结果，这个结果是从公共成员digestHexStr取得的．
    */
        public String getMD5ofStr(byte[] inbuf,int length) {
            md5Init();
            md5Update(inbuf, length);
            md5Final();
            digestHexStr = "";
            for (int i = 0; i < 16; i++) {
                digestHexStr += byteHEX(digest[i]);
            }
            return digestHexStr;

        }
        public byte[] getMD5ofBytes(byte[] inbuf,int length) {
            md5Init();
            md5Update(inbuf, length);
            md5Final();
            return digest;
        }
        public String getMD5ofStr(String inbuf) {
            md5Init();
            md5Update(inbuf.getBytes(), inbuf.length());
            md5Final();
            digestHexStr = "";
            for (int i = 0; i < 16; i++) {
                digestHexStr += byteHEX(digest[i]);
            }
            return digestHexStr;
        }
        // 这是MD5这个类的标准构造函数，JavaBean要求有一个public的并且没有参数的构造函数
        public MD5() {
            md5Init();

            return;
        }



        /* md5Init是一个初始化函数，初始化核心变量，装入标准的幻数 */
        private void md5Init() {
            count[0] = 0L;
            count[1] = 0L;
            ///* Load magic initialization constants.

            state[0] = 0x67452301L;
            state[1] = 0xefcdab89L;
            state[2] = 0x98badcfeL;
            state[3] = 0x10325476L;

            return;
        }
        /* F, G, H ,I 是4个基本的MD5函数，在原始的MD5的C实现中，由于它们是
        简单的位运算，可能出于效率的考虑把它们实现成了宏，在java中，我们把它们
     　　实现成了private方法，名字保持了原来C中的。 */

        private long F(long x, long y, long z) {
            return (x & y) | ((~x) & z);

        }
        private long G(long x, long y, long z) {
            return (x & z) | (y & (~z));

        }
        private long H(long x, long y, long z) {
            return x ^ y ^ z;
        }

        private long I(long x, long y, long z) {
            return y ^ (x | (~z));
        }

       /*
          FF,GG,HH和II将调用F,G,H,I进行近一步变换
          FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
          Rotation is separate from addition to prevent recomputation.
       */

        private long FF(long a, long b, long c, long d, long x, long s,
                long ac) {
                a += F (b, c, d) + x + ac;
                a = ((int) a << s) | ((int) a >>> (32 - s));
                a += b;
                return a;
        }

        private long GG(long a, long b, long c, long d, long x, long s,
                        long ac) {
            a += G (b, c, d) + x + ac;
            a = ((int) a << s) | ((int) a >>> (32 - s));
            a += b;
            return a;
        }
        private long HH(long a, long b, long c, long d, long x, long s,
                long ac) {
                a += H (b, c, d) + x + ac;
                a = ((int) a << s) | ((int) a >>> (32 - s));
                a += b;
                return a;
        }
        private long II(long a, long b, long c, long d, long x, long s,
                        long ac) {
            a += I (b, c, d) + x + ac;
            a = ((int) a << s) | ((int) a >>> (32 - s));
            a += b;
            return a;
        }
        /*
         md5Update是MD5的主计算过程，inbuf是要变换的字节串，inputlen是长度，这个
         函数由getMD5ofStr调用，调用之前需要调用md5init，因此把它设计成private的
        */
        private void md5Update(byte[] inbuf, int inputLen) {

            int i, index, partLen;
            byte[] block = new byte[64];
            index = (int)(count[0] >>> 3) & 0x3F;
            // /* Update number of bits */
            if ((count[0] += (inputLen << 3)) < (inputLen << 3))
                    count[1]++;
            count[1] += (inputLen >>> 29);

            partLen = 64 - index;

            // Transform as many times as possible.
            if (inputLen >= partLen) {
                    md5Memcpy(buffer, inbuf, index, 0, partLen);
                    md5Transform(buffer);

                    for (i = partLen; i + 63 < inputLen; i += 64) {

                            md5Memcpy(block, inbuf, 0, i, 64);
                            md5Transform (block);
                    }
                    index = 0;

            } else

                    i = 0;

            ///* Buffer remaining input */
            md5Memcpy(buffer, inbuf, index, i, inputLen - i);

        }

        /*
          md5Final整理和填写输出结果
        */
        private void md5Final () {
            byte[] bits = new byte[8];
            int index, padLen;

            ///* Save number of bits */
            Encode (bits, count, 8);

            ///* Pad out to 56 mod 64.
            index = (int)(count[0] >>> 3) & 0x3f;
            padLen = (index < 56) ? (56 - index) : (120 - index);
            md5Update (PADDING, padLen);

            ///* 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;
        }
}