package
				 com.chinajavaworld.util;
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import java.lang.reflect.*;
import java.io.*;
/*************************************************
md5 類實現了RSA Data Security, Inc.在提交給IETF
的RFC1321中的MD5 message-digest 算法。
*************************************************/
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publicclass MD5 {
/* 下面這些S11-S44實際上是一個4*4的矩陣，在原始的C實現中是用#define 實現的，
        這里把它們實現成為static final是表示了只讀，切能在同一個進程空間內的多個
        Instance間共享*/
staticfinalint S11 = 7;
staticfinalint S12 = 12;
staticfinalint S13 = 17;
staticfinalint S14 = 22;
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staticfinalint S21 = 5;
staticfinalint S22 = 9;
staticfinalint S23 = 14;
staticfinalint S24 = 20;
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staticfinalint S31 = 4;
staticfinalint S32 = 11;
staticfinalint S33 = 16;
staticfinalint S34 = 23;
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staticfinalint S41 = 6;
staticfinalint S42 = 10;
staticfinalint S43 = 15;
staticfinalint S44 = 21;
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staticfinalbyte[] 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 };
/* 下面的三個成員是MD5計算過程中用到的3個核心數據，在原始的C實現中
           被定義到MD5_CTX結構中

         */
privatelong[] state = newlong[4];  // state (ABCD)
privatelong[] count = newlong[2];  // number of bits, modulo 2^64 (lsb first)
privatebyte[] buffer = newbyte[64]; // input buffer
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/* digestHexStr是MD5的唯一一個公共成員，是最新一次計算結果的
        　 16進制ASCII表示.
        */
public String digestHexStr;
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/* digest,是最新一次計算結果的2進制內部表示，表示128bit的MD5值.
        */
privatebyte[] digest = newbyte[16];
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/*
          getMD5ofStr是類MD5最主要的公共方法，入口參數是你想要進行MD5變換的字符串
          返回的是變換完的結果，這個結果是從公共成員digestHexStr取得的．
        */
public String getMD5ofStr(String inbuf) {
                md5Init();
try{
                  md5Update(inbuf.getBytes("GBK"),
                            inbuf.getBytes("GBK").length);
}
catch (UnsupportedEncodingException ex) {
}
                md5Final();
                digestHexStr = "";
for (int i = 0; i < 16; i++) {
                        digestHexStr += byteHEX(digest[i]);
}
return digestHexStr;
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}
// 這是MD5這個類的標準構造函數，JavaBean要求有一個public的并且沒有參數的構造函數
public MD5() {
                md5Init();
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return;
}
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/* md5Init是一個初始化函數，初始化核心變量，裝入標準的幻數 */
privatevoid md5Init() {
                count[0] = 0L;
                count[1] = 0L;
///* Load magic initialization constants.
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                state[0] = 0x67452301L;
                state[1] = 0xefcdab89L;
                state[2] = 0x98badcfeL;
                state[3] = 0x10325476L;
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return;
}
/* F, G, H ,I 是4個基本的MD5函數，在原始的MD5的C實現中，由于它們是
        簡單的位運算，可能出于效率的考慮把它們實現成了宏，在java中，我們把它們
     　　實現成了private方法，名字保持了原來C中的。 */
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privatelong F(long x, long y, long z) {
return (x & y) | ((~x) & z);
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}
privatelong G(long x, long y, long z) {
return (x & z) | (y & (~z));
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}
privatelong H(long x, long y, long z) {
return x ^ y ^ z;
}
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privatelong I(long x, long y, long z) {
return y ^ (x | (~z));
}
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/*
          FF,GG,HH和II將調用F,G,H,I進行近一步變換
          FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
          Rotation is separate from addition to prevent recomputation.
       */
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privatelong 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;
}
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privatelong 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;
}
privatelong 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;
}
privatelong 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的主計算過程，inbuf是要變換的字節串，inputlen是長度，這個
         函數由getMD5ofStr調用，調用之前需要調用md5init，因此把它設計成private的
        */
privatevoid md5Update(byte[] inbuf, int inputLen) {
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int i, index, partLen;
byte[] block = newbyte[64];
                index = (int)(count[0] >>> 3) & 0x3F;
// /* Update number of bits */
if ((count[0] += (inputLen << 3)) < (inputLen << 3))
                        count[1]++;
                count[1] += (inputLen >>> 29);
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                partLen = 64 - index;
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// Transform as many times as possible.
if (inputLen >= partLen) {
                        md5Memcpy(buffer, inbuf, index, 0, partLen);
                        md5Transform(buffer);
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for (i = partLen; i + 63 < inputLen; i += 64) {
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                                md5Memcpy(block, inbuf, 0, i, 64);
                                md5Transform (block);
}
                        index = 0;
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}else
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                        i = 0;
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///* Buffer remaining input */
                md5Memcpy(buffer, inbuf, index, i, inputLen - i);
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}
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/*
          md5Final整理和填寫輸出結果
        */
privatevoid md5Final () {
byte[] bits = newbyte[8];
int index, padLen;
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///* Save number of bits */
                Encode (bits, count, 8);
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///* Pad out to 56 mod 64.
                index = (int)(count[0] >>> 3) & 0x3f;
                padLen = (index < 56) ? (56 - index) : (120 - index);
                md5Update (PADDING, padLen);
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///* Append length (before padding) */
                md5Update(bits, 8);
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///* Store state in digest */
                Encode (digest, state, 16);
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}
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/* md5Memcpy是一個內部使用的byte數組的塊拷貝函數，從input的inpos開始把len長度的
　　　　　 字節拷貝到output的outpos位置開始
        */
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privatevoid md5Memcpy (byte[] output, byte[] input,
int outpos, int inpos, int len)
{
int i;
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for (i = 0; i < len; i++)
                        output[outpos + i] = input[inpos + i];
}
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/*
           md5Transform是MD5核心變換程序，有md5Update調用，block是分塊的原始字節
        */
privatevoid md5Transform (byte block[]) {
long a = state[0], b = state[1], c = state[2], d = state[3];
long[] x = newlong[16];
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                Decode (x, block, 64);
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/* 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 */
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/* 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 */
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/* 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 */
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/* 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 */
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                state[0] += a;
                state[1] += b;
                state[2] += c;
                state[3] += d;
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}
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/*Encode把long數組按順序拆成byte數組，因為java的long類型是64bit的，
          只拆低32bit，以適應原始C實現的用途
        */
privatevoid Encode (byte[] output, long[] input, int len) {
int i, j;
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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);
}
}
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/*Decode把byte數組按順序合成成long數組，因為java的long類型是64bit的，
          只合成低32bit，高32bit清零，以適應原始C實現的用途
        */
privatevoid Decode (long[] output, byte[] input, int len) {
int i, j;
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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);
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return;
}
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/*
          b2iu是我寫的一個把byte按照不考慮正負號的原則的＂升位＂程序，因為java沒有unsigned運算
        */
publicstaticlong b2iu(byte b) {
return b < 0 ? b & 0x7F + 128 : b;
}
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/*byteHEX()，用來把一個byte類型的數轉換成十六進制的ASCII表示，
        　因為java中的byte的toString無法實現這一點，我們又沒有C語言中的
          sprintf(outbuf,"%02X",ib)
        */
publicstatic String byteHEX(byte ib) {
char[] Digit = {'0','1','2','3','4','5','6','7','8','9',
'A','B','C','D','E','F'};
char [] ob = newchar[2];
                ob[0] = Digit[(ib >>> 4) & 0X0F];
                ob[1] = Digit[ib & 0X0F];
                String s = new String(ob);
return s;
}
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publicstaticvoid main(String args[]) {
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                MD5 m = new MD5();
if (Array.getLength(args) == 0) {//如果沒有參數，執行標準的Test Suite
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                               System.out.println("MD5 Test suite:");
                        System.out.println("MD5(\"\"):"+m.getMD5ofStr(""));
                        System.out.println("MD5(\"a\"):"+m.getMD5ofStr("a"));
                        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]));
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}
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}