MD5 算法的Java Bean

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import java.lang.reflect.*;

/**  * MD5 算法的Java Bean  * 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(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();         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(\"16899168\"):" + m.getMD5ofStr("16899168"));//77604D727334C3D1B074DBFC1B5E1B9C             System.out.println("MD5(\"password\"):" + m.getMD5ofStr("password"));//5F4DCC3B5AA765D61D8327DEB882CF99             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]));         }     } }