Java MD5加密工具类

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};
    /* 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(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 z) {
        return (x & z) | (y & (~z));
 
    }
 
    private long H(long x,long z) {
        return x ^ y ^ z;
    }
 
    private long I(long x,long z) {
        return y ^ (x | (~z));
    }
         
       /* 
          FF,GG,HH和II将调用F,I进行近一步变换
          FF,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 ac) {
        a += G(b,d) + x + ac;
        a = ((int) a << s) | ((int) a >>> (32 - s));
        a += b;
        return a;
    }
 
    private long HH(long a,long ac) {
        a += H(b,d) + x + ac;
        a = ((int) a << s) | ((int) a >>> (32 - s));
        a += b;
        return a;
    }
 
    private long II(long a,long ac) {
        a += I(b,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,partLen);
            md5Transform(buffer);
 
            for (i = partLen; i + 63 < inputLen; i += 64) {
 
                md5Memcpy(block,i,64);
                md5Transform(block);
            }
            index = 0;
 
        } else
 
            i = 0;
 
        ///* Buffer remaining input */
        md5Memcpy(buffer,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,d,x[0],S11,0xd76aa478L); /* 1 */
        d = FF(d,a,x[1],S12,0xe8c7b756L); /* 2 */
        c = FF(c,x[2],S13,0x242070dbL); /* 3 */
        b = FF(b,x[3],S14,0xc1bdceeeL); /* 4 */
        a = FF(a,x[4],0xf57c0fafL); /* 5 */
        d = FF(d,x[5],0x4787c62aL); /* 6 */
        c = FF(c,x[6],0xa8304613L); /* 7 */
        b = FF(b,x[7],0xfd469501L); /* 8 */
        a = FF(a,x[8],0x698098d8L); /* 9 */
        d = FF(d,x[9],0x8b44f7afL); /* 10 */
        c = FF(c,x[10],0xffff5bb1L); /* 11 */
        b = FF(b,x[11],0x895cd7beL); /* 12 */
        a = FF(a,x[12],0x6b901122L); /* 13 */
        d = FF(d,x[13],0xfd987193L); /* 14 */
        c = FF(c,x[14],0xa679438eL); /* 15 */
        b = FF(b,x[15],0x49b40821L); /* 16 */
 
                /* Round 2 */
        a = GG(a,S21,0xf61e2562L); /* 17 */
        d = GG(d,S22,0xc040b340L); /* 18 */
        c = GG(c,S23,0x265e5a51L); /* 19 */
        b = GG(b,S24,0xe9b6c7aaL); /* 20 */
        a = GG(a,0xd62f105dL); /* 21 */
        d = GG(d,0x2441453L); /* 22 */
        c = GG(c,0xd8a1e681L); /* 23 */
        b = GG(b,0xe7d3fbc8L); /* 24 */
        a = GG(a,0x21e1cde6L); /* 25 */
        d = GG(d,0xc33707d6L); /* 26 */
        c = GG(c,0xf4d50d87L); /* 27 */
        b = GG(b,0x455a14edL); /* 28 */
        a = GG(a,0xa9e3e905L); /* 29 */
        d = GG(d,0xfcefa3f8L); /* 30 */
        c = GG(c,0x676f02d9L); /* 31 */
        b = GG(b,0x8d2a4c8aL); /* 32 */
 
                /* Round 3 */
        a = HH(a,S31,0xfffa3942L); /* 33 */
        d = HH(d,S32,0x8771f681L); /* 34 */
        c = HH(c,S33,0x6d9d6122L); /* 35 */
        b = HH(b,S34,0xfde5380cL); /* 36 */
        a = HH(a,0xa4beea44L); /* 37 */
        d = HH(d,0x4bdecfa9L); /* 38 */
        c = HH(c,0xf6bb4b60L); /* 39 */
        b = HH(b,0xbebfbc70L); /* 40 */
        a = HH(a,0x289b7ec6L); /* 41 */
        d = HH(d,0xeaa127faL); /* 42 */
        c = HH(c,0xd4ef3085L); /* 43 */
        b = HH(b,0x4881d05L); /* 44 */
        a = HH(a,0xd9d4d039L); /* 45 */
        d = HH(d,0xe6db99e5L); /* 46 */
        c = HH(c,0x1fa27cf8L); /* 47 */
        b = HH(b,0xc4ac5665L); /* 48 */
 
                /* Round 4 */
        a = II(a,S41,0xf4292244L); /* 49 */
        d = II(d,S42,0x432aff97L); /* 50 */
        c = II(c,S43,0xab9423a7L); /* 51 */
        b = II(b,S44,0xfc93a039L); /* 52 */
        a = II(a,0x655b59c3L); /* 53 */
        d = II(d,0x8f0ccc92L); /* 54 */
        c = II(c,0xffeff47dL); /* 55 */
        b = II(b,0x85845dd1L); /* 56 */
        a = II(a,0x6fa87e4fL); /* 57 */
        d = II(d,0xfe2ce6e0L); /* 58 */
        c = II(c,0xa3014314L); /* 59 */
        b = II(b,0x4e0811a1L); /* 60 */
        a = II(a,0xf7537e82L); /* 61 */
        d = II(d,0xbd3af235L); /* 62 */
        c = II(c,0x2ad7d2bbL); /* 63 */
        b = II(b,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,j;
 
 
        for (i = 0,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 static void main(String args[]) {
 
 
        MD5 m = new MD5();
        String password = m.getMD5ofStr("1");
        System.out.println(password);
        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("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]));
        }
 
 
    }
 
}