java的md5加密类

package com.md5;

/*************************************************

md5类实现了RSADataSecurity,Inc.在提交给IETF

的RFC1321中的MD5message-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staticfinal是表示了只读,切能在同一个进程空间内的多个

Instance间共享*/

staticfinalintS11=7;

staticfinalintS12=12;

staticfinalintS13=17;

        static final int S14 = 22;

        static final int S21 = 5;

staticfinalintS22=9;

staticfinalintS23=14;

        static final int S24 = 20;

        static final int S31 = 4;

staticfinalintS32=11;

staticfinalintS33=16;

        static final int S34 = 23;

        static final int S41 = 6;

staticfinalintS42=10;

staticfinalintS43=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

         */

privatelong[]state=newlong[4];//state(ABCD)

privatelong[]count=newlong[2];//numberofbits,modulo2^64(lsbfirst)

        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.

*/

publicStringgetMD5ofStr(Stringinbuf){

md5Init();

md5Update(inbuf.getBytes(),inbuf.length());

md5Final();

digestHexStr="";

for(inti=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

publicMD5(){

                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 */

privatevoidmd5Init(){

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);

        }

privatelongG(longx,longy,longz){

                return (x & z) | (y & (~z));

        }

privatelongH(longx,longy,longz){

returnx^y^z;

        }

        private long I(long x, long y, long z) {

returny^(x|(~z));

        }

       /*

FF,GG,HH和II将调用F,G,H,I进行近一步变换

FF,GG,HH,andIItransformationsforrounds1,2,3,and4.

Rotationisseparatefromadditiontopreventrecomputation.

       */

        private long FF(long a, long b, long c, long d, long x, long s,

longac){

a+=F(b,c,d)+x+ac;

a=((int)a<<s)|((int)a>>>(32-s));

a+=b;

returna;

        }

        private long GG(long a, long b, long c, long d, long x, long s,

longac){

a+=G(b,c,d)+x+ac;

a=((int)a<<s)|((int)a>>>(32-s));

a+=b;

returna;

}

privatelongHH(longa,longb,longc,longd,longx,longs,

longac){

a+=H(b,c,d)+x+ac;

a=((int)a<<s)|((int)a>>>(32-s));

a+=b;

returna;

}

privatelongII(longa,longb,longc,longd,longx,longs,

longac){

a+=I(b,c,d)+x+ac;

a=((int)a<<s)|((int)a>>>(32-s));

a+=b;

returna;

}

/*

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=newbyte[64];

index=(int)(count[0]>>>3)&0x3F;

///*Updatenumberofbits*/

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

*/

privatevoidmd5Final(){

byte[]bits=newbyte[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,

intoutpos,intinpos,intlen)

{

                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

*/

privatevoidmd5Transform(byteblock[]){

longa=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

*/

privatevoidEncode(byte[]output,long[]input,intlen){

                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

*/

privatevoidDecode(long[]output,byte[]input,intlen){

                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

*/

publicstaticlongb2iu(byteb){

returnb<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)

*/

publicstaticStringbyteHEX(byteib){

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];

Strings=newString(ob);

returns;

}

publicstaticvoidmain(Stringargs[])

{

MD5md5=newMD5();

System.out.println(md5.getMD5ofStr("haha"));

  }

}

 

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