1 /************************************************* 2 md5 类实现了RSA Data Security, Inc.在提交给IETF 3 的RFC1321中的MD5 message-digest 算法。 4 *************************************************/ 5 public class MD5 { 6 /* 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， 7 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 8 Instance间共享*/ 9 static final int S11 = 7; 10 static final int S12 = 12; 11 static final int S13 = 17; 12 static final int S14 = 22; 13 14 static final int S21 = 5; 15 static final int S22 = 9; 16 static final int S23 = 14; 17 static final int S24 = 20; 18 19 static final int S31 = 4; 20 static final int S32 = 11; 21 static final int S33 = 16; 22 static final int S34 = 23; 23 24 static final int S41 = 6; 25 static final int S42 = 10; 26 static final int S43 = 15; 27 static final int S44 = 21; 28 29 static final byte[] PADDING = { -128, 0, 0, 0, 0, 0, 0, 0, 0, 30 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 31 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 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, 0 }; 33 /* 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 34 被定义到MD5_CTX结构中 35 36 */ 37 private long[] state = new long[4]; // state (ABCD) 38 private long[] count = new long[2]; // number of bits, modulo 2^64 (lsb first) 39 private byte[] buffer = new byte[64]; // input buffer 40 41 /* digestHexStr是MD5的唯一一个公共成员，是最新一次计算结果的 42 16进制ASCII表示. 43 */ 44 public String digestHexStr; 45 46 /* digest,是最新一次计算结果的2进制内部表示，表示128bit的MD5值. 47 */ 48 private byte[] digest = new byte[16]; 49 50 /* 51 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 52 返回的是变换完的结果，这个结果是从公共成员digestHexStr取得的． 53 */ 54 public String getMD5ofStr(String inbuf) { 55 md5Init(); 56 md5Update(inbuf.getBytes(), inbuf.length()); 57 md5Final(); 58 digestHexStr = ""; 59 for (int i = 0; i < 16; i++) { 60 digestHexStr += byteHEX(digest[i]); 61 } 62 return digestHexStr; 63 64 } 65 // 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 66 public MD5() { 67 md5Init(); 68 69 return; 70 } 71 /* md5Init是一个初始化函数，初始化核心变量，装入标准的幻数 */ 72 private void md5Init() { 73 count[0] = 0L; 74 count[1] = 0L; 75 ///* Load magic initialization constants. 76 77 state[0] = 0x67452301L; 78 state[1] = 0xefcdab89L; 79 state[2] = 0x98badcfeL; 80 state[3] = 0x10325476L; 81 82 return; 83 } 84 /* 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 85 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 86 实现成了private方法，名字保持了原来C中的。 */ 87 88 private long F(long x, long y, long z) { 89 return (x & y) | ((~x) & z); 90 91 } 92 private long G(long x, long y, long z) { 93 return (x & z) | (y & (~z)); 94 95 } 96 private long H(long x, long y, long z) { 97 return x ^ y ^ z; 98 } 99 100 private long I(long x, long y, long z) { 101 return y ^ (x | (~z)); 102 } 103 104 /* 105 FF,GG,HH和II将调用F,G,H,I进行近一步变换 106 FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4. 107 Rotation is separate from addition to prevent recomputation. 108 */ 109 110 private long FF(long a, long b, long c, long d, long x, long s, 111 long ac) { 112 a += F (b, c, d) + x + ac; 113 a = ((int) a << s) | ((int) a >>> (32 - s)); 114 a += b; 115 return a; 116 } 117 118 private long GG(long a, long b, long c, long d, long x, long s, 119 long ac) { 120 a += G (b, c, d) + x + ac; 121 a = ((int) a << s) | ((int) a >>> (32 - s)); 122 a += b; 123 return a; 124 } 125 private long HH(long a, long b, long c, long d, long x, long s, 126 long ac) { 127 a += H (b, c, d) + x + ac; 128 a = ((int) a << s) | ((int) a >>> (32 - s)); 129 a += b; 130 return a; 131 } 132 private long II(long a, long b, long c, long d, long x, long s, 133 long ac) { 134 a += I (b, c, d) + x + ac; 135 a = ((int) a << s) | ((int) a >>> (32 - s)); 136 a += b; 137 return a; 138 } 139 /* 140 md5Update是MD5的主计算过程，inbuf是要变换的字节串，inputlen是长度，这个 141 函数由getMD5ofStr调用，调用之前需要调用md5init，因此把它设计成private的 142 */ 143 private void md5Update(byte[] inbuf, int inputLen) { 144 145 int i, index, partLen; 146 byte[] block = new byte[64]; 147 index = (int)(count[0] >>> 3) & 0x3F; 148 // /* Update number of bits */ 149 if ((count[0] += (inputLen << 3)) < (inputLen << 3)) 150 count[1]++; 151 count[1] += (inputLen >>> 29); 152 153 partLen = 64 - index; 154 155 // Transform as many times as possible. 156 if (inputLen >= partLen) { 157 md5Memcpy(buffer, inbuf, index, 0, partLen); 158 md5Transform(buffer); 159 160 for (i = partLen; i + 63 < inputLen; i += 64) { 161 162 md5Memcpy(block, inbuf, 0, i, 64); 163 md5Transform (block); 164 } 165 index = 0; 166 167 } else 168 169 i = 0; 170 171 ///* Buffer remaining input */ 172 md5Memcpy(buffer, inbuf, index, i, inputLen - i); 173 174 } 175 176 /* 177 md5Final整理和填写输出结果 178 */ 179 private void md5Final () { 180 byte[] bits = new byte[8]; 181 int index, padLen; 182 183 ///* Save number of bits */ 184 Encode (bits, count, 8); 185 186 ///* Pad out to 56 mod 64. 187 index = (int)(count[0] >>> 3) & 0x3f; 188 padLen = (index < 56) ? (56 - index) : (120 - index); 189 md5Update (PADDING, padLen); 190 191 ///* Append length (before padding) */ 192 md5Update(bits, 8); 193 194 ///* Store state in digest */ 195 Encode (digest, state, 16); 196 197 } 198 199 /* 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 200 字节拷贝到output的outpos位置开始 201 */ 202 203 private void md5Memcpy (byte[] output, byte[] input, 204 int outpos, int inpos, int len) 205 { 206 int i; 207 208 for (i = 0; i < len; i++) 209 output[outpos + i] = input[inpos + i]; 210 } 211 212 /* 213 md5Transform是MD5核心变换程序，有md5Update调用，block是分块的原始字节 214 */ 215 private void md5Transform (byte block[]) { 216 long a = state[0], b = state[1], c = state[2], d = state[3]; 217 long[] x = new long[16]; 218 219 Decode (x, block, 64); 220 221 /* Round 1 */ 222 a = FF (a, b, c, d, x[0], S11, 0xd76aa478L); /* 1 */ 223 d = FF (d, a, b, c, x[1], S12, 0xe8c7b756L); /* 2 */ 224 c = FF (c, d, a, b, x[2], S13, 0x242070dbL); /* 3 */ 225 b = FF (b, c, d, a, x[3], S14, 0xc1bdceeeL); /* 4 */ 226 a = FF (a, b, c, d, x[4], S11, 0xf57c0fafL); /* 5 */ 227 d = FF (d, a, b, c, x[5], S12, 0x4787c62aL); /* 6 */ 228 c = FF (c, d, a, b, x[6], S13, 0xa8304613L); /* 7 */ 229 b = FF (b, c, d, a, x[7], S14, 0xfd469501L); /* 8 */ 230 a = FF (a, b, c, d, x[8], S11, 0x698098d8L); /* 9 */ 231 d = FF (d, a, b, c, x[9], S12, 0x8b44f7afL); /* 10 */ 232 c = FF (c, d, a, b, x[10], S13, 0xffff5bb1L); /* 11 */ 233 b = FF (b, c, d, a, x[11], S14, 0x895cd7beL); /* 12 */ 234 a = FF (a, b, c, d, x[12], S11, 0x6b901122L); /* 13 */ 235 d = FF (d, a, b, c, x[13], S12, 0xfd987193L); /* 14 */ 236 c = FF (c, d, a, b, x[14], S13, 0xa679438eL); /* 15 */ 237 b = FF (b, c, d, a, x[15], S14, 0x49b40821L); /* 16 */ 238 239 /* Round 2 */ 240 a = GG (a, b, c, d, x[1], S21, 0xf61e2562L); /* 17 */ 241 d = GG (d, a, b, c, x[6], S22, 0xc040b340L); /* 18 */ 242 c = GG (c, d, a, b, x[11], S23, 0x265e5a51L); /* 19 */ 243 b = GG (b, c, d, a, x[0], S24, 0xe9b6c7aaL); /* 20 */ 244 a = GG (a, b, c, d, x[5], S21, 0xd62f105dL); /* 21 */ 245 d = GG (d, a, b, c, x[10], S22, 0x2441453L); /* 22 */ 246 c = GG (c, d, a, b, x[15], S23, 0xd8a1e681L); /* 23 */ 247 b = GG (b, c, d, a, x[4], S24, 0xe7d3fbc8L); /* 24 */ 248 a = GG (a, b, c, d, x[9], S21, 0x21e1cde6L); /* 25 */ 249 d = GG (d, a, b, c, x[14], S22, 0xc33707d6L); /* 26 */ 250 c = GG (c, d, a, b, x[3], S23, 0xf4d50d87L); /* 27 */ 251 b = GG (b, c, d, a, x[8], S24, 0x455a14edL); /* 28 */ 252 a = GG (a, b, c, d, x[13], S21, 0xa9e3e905L); /* 29 */ 253 d = GG (d, a, b, c, x[2], S22, 0xfcefa3f8L); /* 30 */ 254 c = GG (c, d, a, b, x[7], S23, 0x676f02d9L); /* 31 */ 255 b = GG (b, c, d, a, x[12], S24, 0x8d2a4c8aL); /* 32 */ 256 257 /* Round 3 */ 258 a = HH (a, b, c, d, x[5], S31, 0xfffa3942L); /* 33 */ 259 d = HH (d, a, b, c, x[8], S32, 0x8771f681L); /* 34 */ 260 c = HH (c, d, a, b, x[11], S33, 0x6d9d6122L); /* 35 */ 261 b = HH (b, c, d, a, x[14], S34, 0xfde5380cL); /* 36 */ 262 a = HH (a, b, c, d, x[1], S31, 0xa4beea44L); /* 37 */ 263 d = HH (d, a, b, c, x[4], S32, 0x4bdecfa9L); /* 38 */ 264 c = HH (c, d, a, b, x[7], S33, 0xf6bb4b60L); /* 39 */ 265 b = HH (b, c, d, a, x[10], S34, 0xbebfbc70L); /* 40 */ 266 a = HH (a, b, c, d, x[13], S31, 0x289b7ec6L); /* 41 */ 267 d = HH (d, a, b, c, x[0], S32, 0xeaa127faL); /* 42 */ 268 c = HH (c, d, a, b, x[3], S33, 0xd4ef3085L); /* 43 */ 269 b = HH (b, c, d, a, x[6], S34, 0x4881d05L); /* 44 */ 270 a = HH (a, b, c, d, x[9], S31, 0xd9d4d039L); /* 45 */ 271 d = HH (d, a, b, c, x[12], S32, 0xe6db99e5L); /* 46 */ 272 c = HH (c, d, a, b, x[15], S33, 0x1fa27cf8L); /* 47 */ 273 b = HH (b, c, d, a, x[2], S34, 0xc4ac5665L); /* 48 */ 274 275 /* Round 4 */ 276 a = II (a, b, c, d, x[0], S41, 0xf4292244L); /* 49 */ 277 d = II (d, a, b, c, x[7], S42, 0x432aff97L); /* 50 */ 278 c = II (c, d, a, b, x[14], S43, 0xab9423a7L); /* 51 */ 279 b = II (b, c, d, a, x[5], S44, 0xfc93a039L); /* 52 */ 280 a = II (a, b, c, d, x[12], S41, 0x655b59c3L); /* 53 */ 281 d = II (d, a, b, c, x[3], S42, 0x8f0ccc92L); /* 54 */ 282 c = II (c, d, a, b, x[10], S43, 0xffeff47dL); /* 55 */ 283 b = II (b, c, d, a, x[1], S44, 0x85845dd1L); /* 56 */ 284 a = II (a, b, c, d, x[8], S41, 0x6fa87e4fL); /* 57 */ 285 d = II (d, a, b, c, x[15], S42, 0xfe2ce6e0L); /* 58 */ 286 c = II (c, d, a, b, x[6], S43, 0xa3014314L); /* 59 */ 287 b = II (b, c, d, a, x[13], S44, 0x4e0811a1L); /* 60 */ 288 a = II (a, b, c, d, x[4], S41, 0xf7537e82L); /* 61 */ 289 d = II (d, a, b, c, x[11], S42, 0xbd3af235L); /* 62 */ 290 c = II (c, d, a, b, x[2], S43, 0x2ad7d2bbL); /* 63 */ 291 b = II (b, c, d, a, x[9], S44, 0xeb86d391L); /* 64 */ 292 293 state[0] += a; 294 state[1] += b; 295 state[2] += c; 296 state[3] += d; 297 298 } 299 300 /*Encode把long数组按顺序拆成byte数组，因为java的long类型是64bit的， 301 只拆低32bit，以适应原始C实现的用途 302 */ 303 private void Encode (byte[] output, long[] input, int len) { 304 int i, j; 305 306 for (i = 0, j = 0; j < len; i++, j += 4) { 307 output[j] = (byte)(input[i] & 0xffL); 308 output[j + 1] = (byte)((input[i] >>> 8) & 0xffL); 309 output[j + 2] = (byte)((input[i] >>> 16) & 0xffL); 310 output[j + 3] = (byte)((input[i] >>> 24) & 0xffL); 311 } 312 } 313 314 /*Decode把byte数组按顺序合成成long数组，因为java的long类型是64bit的， 315 只合成低32bit，高32bit清零，以适应原始C实现的用途 316 */ 317 private void Decode (long[] output, byte[] input, int len) { 318 int i, j; 319 320 321 for (i = 0, j = 0; j < len; i++, j += 4) 322 output[i] = b2iu(input[j]) | 323 (b2iu(input[j + 1]) << 8) | 324 (b2iu(input[j + 2]) << 16) | 325 (b2iu(input[j + 3]) << 24); 326 327 return; 328 } 329 330 /* 331 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 332 */ 333 public static long b2iu(byte b) { 334 return b < 0 ? b & 0x7F + 128 : b; 335 } 336 337 /*byteHEX()，用来把一个byte类型的数转换成十六进制的ASCII表示， 338 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 339 sprintf(outbuf,"%02X",ib) 340 */ 341 public static String byteHEX(byte ib) { 342 char[] Digit = { '0','1','2','3','4','5','6','7','8','9', 343 'A','B','C','D','E','F' }; 344 char [] ob = new char[2]; 345 ob[0] = Digit[(ib >>> 4) & 0X0F]; 346 ob[1] = Digit[ib & 0X0F]; 347 String s = new String(ob); 348 return s; 349 } 350 public static void main(String args[]){ 351 MD5 md5 = new MD5(); 352 System.out.println(md5.getMD5ofStr("admin")); 353 } 354 }