//来自网络。
1
package com.kai;2

/** *//*************************************************3
md5 类实现了RSA Data Security, Inc.在提交给IETF4
的RFC1321中的MD5 message-digest 算法。5
*************************************************/6

7

public class MD5
{8

/**//* 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,9
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10
Instance间共享*/11
static final int S11 = 7;12
static final int S12 = 12;13
static final int S13 = 17;14
static final int S14 = 22;15

16
static final int S21 = 5;17
static final int S22 = 9;18
static final int S23 = 14;19
static final int S24 = 20;20

21
static final int S31 = 4;22
static final int S32 = 11;23
static final int S33 = 16;24
static final int S34 = 23;25

26
static final int S41 = 6;27
static final int S42 = 10;28
static final int S43 = 15;29
static final int S44 = 21;30

31

static final byte[] PADDING =
{ -128, 0, 0, 0, 0, 0, 0, 0, 0,32
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,33
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,34
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };35

/**//* 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36
被定义到MD5_CTX结构中37

38
*/39
private long[] state = new long[4]; // state (ABCD)40
private long[] count = new long[2]; // number of bits, modulo 2^64 (lsb first)41
private byte[] buffer = new byte[64]; // input buffer42

43

/**//* digestHexStr是MD5的唯一一个公共成员,是最新一次计算结果的44
16进制ASCII表示.45
*/46
public String digestHexStr;47

48

/**//* digest,是最新一次计算结果的2进制内部表示,表示128bit的MD5值.49
*/50
private byte[] digest = new byte[16];51

52

/**//*53
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54
返回的是变换完的结果,这个结果是从公共成员digestHexStr取得的.55
*/56

public String getMD5ofStr(String inbuf)
{57
md5Init();58
md5Update(inbuf.getBytes(), inbuf.length());59
md5Final();60
digestHexStr = "";61

for (int i = 0; i < 16; i++)
{62
digestHexStr += byteHEX(digest[i]);63
}64
return digestHexStr;65

66
}67
// 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68

public MD5()
{69
md5Init();70

71
return;72
}73

74
75

76

/**//* md5Init是一个初始化函数,初始化核心变量,装入标准的幻数 */77

private void md5Init()
{78
count[0] = 0L;79
count[1] = 0L;80
///* Load magic initialization constants.81

82
state[0] = 0x67452301L;83
state[1] = 0xefcdab89L;84
state[2] = 0x98badcfeL;85
state[3] = 0x10325476L;86

87
return;88
}89

/**//* 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90
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91
实现成了private方法,名字保持了原来C中的。 */92

93

private long F(long x, long y, long z)
{94
return (x & y) | ((~x) & z);95

96
}97

private long G(long x, long y, long z)
{98
return (x & z) | (y & (~z));99

100
}101

private long H(long x, long y, long z)
{102
return x ^ y ^ z;103
}104

105

private long I(long x, long y, long z)
{106
return y ^ (x | (~z));107
}108

109

/**//*110
FF,GG,HH和II将调用F,G,H,I进行近一步变换111
FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.112
Rotation is separate from addition to prevent recomputation.113
*/114

115
private long FF(long a, long b, long c, long d, long x, long s,116

long ac)
{117
a += F (b, c, d) + x + ac;118
a = ((int) a << s) | ((int) a >>> (32 - s));119
a += b;120
return a;121
}122

123
private long GG(long a, long b, long c, long d, long x, long s,124

long ac)
{125
a += G (b, c, d) + x + ac;126
a = ((int) a << s) | ((int) a >>> (32 - s));127
a += b;128
return a;129
}130
private long HH(long a, long b, long c, long d, long x, long s,131

long ac)
{132
a += H (b, c, d) + x + ac;133
a = ((int) a << s) | ((int) a >>> (32 - s));134
a += b;135
return a;136
}137
private long II(long a, long b, long c, long d, long x, long s,138

long ac)
{139
a += I (b, c, d) + x + ac;140
a = ((int) a << s) | ((int) a >>> (32 - s));141
a += b;142
return a;143
}144

/**//*145
md5Update是MD5的主计算过程,inbuf是要变换的字节串,inputlen是长度,这个146
函数由getMD5ofStr调用,调用之前需要调用md5init,因此把它设计成private的147
*/148

private void md5Update(byte[] inbuf, int inputLen)
{149

150
int i, index, partLen;151
byte[] block = new byte[64];152
index = (int)(count[0] >>> 3) & 0x3F;153
// /* Update number of bits */154
if ((count[0] += (inputLen << 3)) < (inputLen << 3))155
count[1]++;156
count[1] += (inputLen >>> 29);157

158
partLen = 64 - index;159

160
// Transform as many times as possible.161

if (inputLen >= partLen)
{162
md5Memcpy(buffer, inbuf, index, 0, partLen);163
md5Transform(buffer);164

165

for (i = partLen; i + 63 < inputLen; i += 64)
{166

167
md5Memcpy(block, inbuf, 0, i, 64);168
md5Transform (block);169
}170
index = 0;171

172
} else173

174
i = 0;175

176
///* Buffer remaining input */177
md5Memcpy(buffer, inbuf, index, i, inputLen - i);178

179
}180

181

/**//*182
md5Final整理和填写输出结果183
*/184

private void md5Final ()
{185
byte[] bits = new byte[8];186
int index, padLen;187

188
///* Save number of bits */189
Encode (bits, count, 8);190

191
///* Pad out to 56 mod 64.192
index = (int)(count[0] >>> 3) & 0x3f;193
padLen = (index < 56) ? (56 - index) : (120 - index);194
md5Update (PADDING, padLen);195

196
///* Append length (before padding) */197
md5Update(bits, 8);198

199
///* Store state in digest */200
Encode (digest, state, 16);201

202
}203

204

/**//* 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205
字节拷贝到output的outpos位置开始206
*/207

208
private void md5Memcpy (byte[] output, byte[] input,209
int outpos, int inpos, int len)210

{211
int i;212

213
for (i = 0; i < len; i++)214
output[outpos + i] = input[inpos + i];215
}216

217

/**//*218
md5Transform是MD5核心变换程序,有md5Update调用,block是分块的原始字节219
*/220

private void md5Transform (byte block[])
{221
long a = state[0], b = state[1], c = state[2], d = state[3];222
long[] x = new long[16];223

224
Decode (x, block, 64);225

226

/**//* Round 1 */227

a = FF (a, b, c, d, x[0], S11, 0xd76aa478L); /**//* 1 */228

d = FF (d, a, b, c, x[1], S12, 0xe8c7b756L); /**//* 2 */229

c = FF (c, d, a, b, x[2], S13, 0x242070dbL); /**//* 3 */230

b = FF (b, c, d, a, x[3], S14, 0xc1bdceeeL); /**//* 4 */231

a = FF (a, b, c, d, x[4], S11, 0xf57c0fafL); /**//* 5 */232

d = FF (d, a, b, c, x[5], S12, 0x4787c62aL); /**//* 6 */233

c = FF (c, d, a, b, x[6], S13, 0xa8304613L); /**//* 7 */234

b = FF (b, c, d, a, x[7], S14, 0xfd469501L); /**//* 8 */235

a = FF (a, b, c, d, x[8], S11, 0x698098d8L); /**//* 9 */236

d = FF (d, a, b, c, x[9], S12, 0x8b44f7afL); /**//* 10 */237

c = FF (c, d, a, b, x[10], S13, 0xffff5bb1L); /**//* 11 */238

b = FF (b, c, d, a, x[11], S14, 0x895cd7beL); /**//* 12 */239

a = FF (a, b, c, d, x[12], S11, 0x6b901122L); /**//* 13 */240

d = FF (d, a, b, c, x[13], S12, 0xfd987193L); /**//* 14 */241

c = FF (c, d, a, b, x[14], S13, 0xa679438eL); /**//* 15 */242

b = FF (b, c, d, a, x[15], S14, 0x49b40821L); /**//* 16 */243

244

/**//* Round 2 */245

a = GG (a, b, c, d, x[1], S21, 0xf61e2562L); /**//* 17 */246

d = GG (d, a, b, c, x[6], S22, 0xc040b340L); /**//* 18 */247

c = GG (c, d, a, b, x[11], S23, 0x265e5a51L); /**//* 19 */248

b = GG (b, c, d, a, x[0], S24, 0xe9b6c7aaL); /**//* 20 */249

a = GG (a, b, c, d, x[5], S21, 0xd62f105dL); /**//* 21 */250

d = GG (d, a, b, c, x[10], S22, 0x2441453L); /**//* 22 */251

c = GG (c, d, a, b, x[15], S23, 0xd8a1e681L); /**//* 23 */252

b = GG (b, c, d, a, x[4], S24, 0xe7d3fbc8L); /**//* 24 */253

a = GG (a, b, c, d, x[9], S21, 0x21e1cde6L); /**//* 25 */254

d = GG (d, a, b, c, x[14], S22, 0xc33707d6L); /**//* 26 */255

c = GG (c, d, a, b, x[3], S23, 0xf4d50d87L); /**//* 27 */256

b = GG (b, c, d, a, x[8], S24, 0x455a14edL); /**//* 28 */257

a = GG (a, b, c, d, x[13], S21, 0xa9e3e905L); /**//* 29 */258

d = GG (d, a, b, c, x[2], S22, 0xfcefa3f8L); /**//* 30 */259

c = GG (c, d, a, b, x[7], S23, 0x676f02d9L); /**//* 31 */260

b = GG (b, c, d, a, x[12], S24, 0x8d2a4c8aL); /**//* 32 */261

262

/**//* Round 3 */263

a = HH (a, b, c, d, x[5], S31, 0xfffa3942L); /**//* 33 */264

d = HH (d, a, b, c, x[8], S32, 0x8771f681L); /**//* 34 */265

c = HH (c, d, a, b, x[11], S33, 0x6d9d6122L); /**//* 35 */266

b = HH (b, c, d, a, x[14], S34, 0xfde5380cL); /**//* 36 */267

a = HH (a, b, c, d, x[1], S31, 0xa4beea44L); /**//* 37 */268

d = HH (d, a, b, c, x[4], S32, 0x4bdecfa9L); /**//* 38 */269

c = HH (c, d, a, b, x[7], S33, 0xf6bb4b60L); /**//* 39 */270

b = HH (b, c, d, a, x[10], S34, 0xbebfbc70L); /**//* 40 */271

a = HH (a, b, c, d, x[13], S31, 0x289b7ec6L); /**//* 41 */272

d = HH (d, a, b, c, x[0], S32, 0xeaa127faL); /**//* 42 */273

c = HH (c, d, a, b, x[3], S33, 0xd4ef3085L); /**//* 43 */274

b = HH (b, c, d, a, x[6], S34, 0x4881d05L); /**//* 44 */275

a = HH (a, b, c, d, x[9], S31, 0xd9d4d039L); /**//* 45 */276

d = HH (d, a, b, c, x[12], S32, 0xe6db99e5L); /**//* 46 */277

c = HH (c, d, a, b, x[15], S33, 0x1fa27cf8L); /**//* 47 */278

b = HH (b, c, d, a, x[2], S34, 0xc4ac5665L); /**//* 48 */279

280

/**//* Round 4 */281

a = II (a, b, c, d, x[0], S41, 0xf4292244L); /**//* 49 */282

d = II (d, a, b, c, x[7], S42, 0x432aff97L); /**//* 50 */283

c = II (c, d, a, b, x[14], S43, 0xab9423a7L); /**//* 51 */284

b = II (b, c, d, a, x[5], S44, 0xfc93a039L); /**//* 52 */285

a = II (a, b, c, d, x[12], S41, 0x655b59c3L); /**//* 53 */286

d = II (d, a, b, c, x[3], S42, 0x8f0ccc92L); /**//* 54 */287

c = II (c, d, a, b, x[10], S43, 0xffeff47dL); /**//* 55 */288

b = II (b, c, d, a, x[1], S44, 0x85845dd1L); /**//* 56 */289

a = II (a, b, c, d, x[8], S41, 0x6fa87e4fL); /**//* 57 */290

d = II (d, a, b, c, x[15], S42, 0xfe2ce6e0L); /**//* 58 */291

c = II (c, d, a, b, x[6], S43, 0xa3014314L); /**//* 59 */292

b = II (b, c, d, a, x[13], S44, 0x4e0811a1L); /**//* 60 */293

a = II (a, b, c, d, x[4], S41, 0xf7537e82L); /**//* 61 */294

d = II (d, a, b, c, x[11], S42, 0xbd3af235L); /**//* 62 */295

c = II (c, d, a, b, x[2], S43, 0x2ad7d2bbL); /**//* 63 */296

b = II (b, c, d, a, x[9], S44, 0xeb86d391L); /**//* 64 */297

298
state[0] += a;299
state[1] += b;300
state[2] += c;301
state[3] += d;302

303
}304

305

/**//*Encode把long数组按顺序拆成byte数组,因为java的long类型是64bit的,306
只拆低32bit,以适应原始C实现的用途307
*/308

private void Encode (byte[] output, long[] input, int len)
{309
int i, j;310

311

for (i = 0, j = 0; j < len; i++, j += 4)
{312
output[j] = (byte)(input[i] & 0xffL);313
output[j + 1] = (byte)((input[i] >>> 8) & 0xffL);314
output[j + 2] = (byte)((input[i] >>> 16) & 0xffL);315
output[j + 3] = (byte)((input[i] >>> 24) & 0xffL);316
}317
}318

319

/**//*Decode把byte数组按顺序合成成long数组,因为java的long类型是64bit的,320
只合成低32bit,高32bit清零,以适应原始C实现的用途321
*/322

private void Decode (long[] output, byte[] input, int len)
{323
int i, j;324

325

326
for (i = 0, j = 0; j < len; i++, j += 4)327
output[i] = b2iu(input[j]) |328
(b2iu(input[j + 1]) << 8) |329
(b2iu(input[j + 2]) << 16) |330
(b2iu(input[j + 3]) << 24);331

332
return;333
}334

335

/**//*336
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337
*/338

public static long b2iu(byte b)
{339
return b < 0 ? b & 0x7F + 128 : b;340
}341

342

/**//*byteHEX(),用来把一个byte类型的数转换成十六进制的ASCII表示,343
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344
sprintf(outbuf,"%02X",ib)345
*/346

public static String byteHEX(byte ib)
{347

char[] Digit =
{ '0','1','2','3','4','5','6','7','8','9',348
'A','B','C','D','E','F' };349
char [] ob = new char[2];350
ob[0] = Digit[(ib >>> 4) & 0X0F];351
ob[1] = Digit[ib & 0X0F];352
String s = new String(ob);353
return s;354
}355
public static void main(String args[])356

{357
MD5 md5=new MD5();358
System.out.println(md5.getMD5ofStr("haha"));359
}360

361
}
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