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[转载]网络上MD5的java实现

原创 Linux操作系统 作者:dinner1007 时间:2019-02-23 22:57:05 0 删除 编辑
网络上MD5的java实现
无意间发现的.不过章章师兄研究的密码学里MD5好象已经用C++实现了.
package com.sinosoftgroup.msd.util;

/**
*
*

Title:


*

Description:


*

Copyright: Copyright (c) 2003


*

Company: 北京中科软件有限公司


* @author not attributable
* @version 1.0
*/
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 */

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, Cool;



///* 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, Cool;



///* 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] >>> Cool & 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]) << Cool |

(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)

{

/* if want to output normal letter please user DigitNormal */

char[] DigitNormal = { '0','1','2','3','4','5','6','7','8','9',

'a','b','c','d','e','f' };

/* if want to output capitalization letter please user DigitCap */

/* char[] DigitCap = { '0','1','2','3','4','5','6','7','8','9',

'A','B','C','D','E','F' }; */

char [] ob = new char[2];

ob[0] = DigitNormal[(ib >>> 4) & 0X0F];

/* ob[0] = DigitCap[(ib >>> 4) & 0X0F]; */

ob[1] = DigitNormal[ib & 0X0F];

/* ob[1] = DigitCap[ib & 0X0F]; */

String s = new String(ob);

return s;

}

}

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