加密算法的java实现源码

java 代码

package com.ctgusec.bean;

/** */
/**
 *
 * @author zhupan
 * @version 1.0
 */
public class MD5 {
    /**//*
         * 下面这些S11-S44实际上是一个4*4的矩阵， 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);

    }

    private  String MD5Front(String str)   {
  str  =  str.replace( ' : ' ,  ' z ' ).replace( ' - ' ,  ' z ' );
   return  str;
 }

    private  String MD5after(String str)   {
  str  =  str.replace( ' 1 ' ,  ' z ' ).replace( ' 2 ' ,  ' h ' ).replace( ' 3 ' ,  ' u ' )
    .replace( ' b ' ,  ' p ' ).replace( ' c ' ,  ' n ' );
   return  str;
 }

    /**//*
         * 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, 0x85845dd