1 public class MD5Code { 2 /* 3 * 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 4 * 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 5 */ 6 static final int S11 = 7; 7 8 static final int S12 = 12; 9 10 static final int S13 = 17; 11 12 static final int S14 = 22; 13 14 static final int S21 = 5; 15 16 static final int S22 = 9; 17 18 static final int S23 = 14; 19 20 static final int S24 = 20; 21 22 static final int S31 = 4; 23 24 static final int S32 = 11; 25 26 static final int S33 = 16; 27 28 static final int S34 = 23; 29 30 static final int S41 = 6; 31 32 static final int S42 = 10; 33 34 static final int S43 = 15; 35 36 static final int S44 = 21; 37 38 static final byte[] PADDING = { -128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 39 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 40 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 41 0, 0, 0, 0, 0, 0, 0 }; 42 43 /* 44 * 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 45 */ 46 private long[] state = new long[4];// state (ABCD) 47 48 private long[] count = new long[2];// number of bits, modulo 2^64 (lsb 49 50 // first) 51 52 private byte[] buffer = new byte[64]; // input buffer 53 54 /* 55 * 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. 56 */ 57 58 public String digestHexStr; 59 60 /* 61 * digest,是最新一次计算结果的2进制内部表示,表示128bit的MD5值. 62 */ 63 private byte[] digest = new byte[16]; 64 65 /* 66 * 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 67 * 返回的是变换完的结果,这个结果是从公共成员digestHexStr取得的. 68 */ 69 public String getMD5ofStr(String inbuf) { 70 md5Init(); 71 md5Update(inbuf.getBytes(), inbuf.length()); 72 md5Final(); 73 digestHexStr = ""; 74 for (int i = 0; i < 16; i++) { 75 digestHexStr += byteHEX(digest[i]); 76 } 77 return digestHexStr; 78 } 79 80 // 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 81 public MD5Code() { 82 md5Init(); 83 return; 84 } 85 86 /* md5Init是一个初始化函数,初始化核心变量,装入标准的幻数 */ 87 private void md5Init() { 88 count[0] = 0L; 89 count[1] = 0L; 90 // /* Load magic initialization constants. 91 state[0] = 0x67452301L; 92 state[1] = 0xefcdab89L; 93 state[2] = 0x98badcfeL; 94 state[3] = 0x10325476L; 95 return; 96 } 97 98 /* 99 * 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 100 * 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。 101 */ 102 private long F(long x, long y, long z) { 103 return (x & y) | ((~x) & z); 104 } 105 106 private long G(long x, long y, long z) { 107 return (x & z) | (y & (~z)); 108 } 109 110 private long H(long x, long y, long z) { 111 return x ^ y ^ z; 112 } 113 114 private long I(long x, long y, long z) { 115 return y ^ (x | (~z)); 116 } 117 118 /* 119 * 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 120 * rounds 1, 2, 3, and 4. Rotation is separate from addition to prevent 121 * recomputation. 122 */ 123 private long FF(long a, long b, long c, long d, long x, long s, long ac) { 124 a += F(b, c, d) + x + ac; 125 a = ((int) a << s) | ((int) a >>> (32 - s)); 126 a += b; 127 return a; 128 } 129 130 private long GG(long a, long b, long c, long d, long x, long s, long ac) { 131 a += G(b, c, d) + x + ac; 132 a = ((int) a << s) | ((int) a >>> (32 - s)); 133 a += b; 134 return a; 135 } 136 137 private long HH(long a, long b, long c, long d, long x, long s, long ac) { 138 a += H(b, c, d) + x + ac; 139 a = ((int) a << s) | ((int) a >>> (32 - s)); 140 a += b; 141 return a; 142 } 143 144 private long II(long a, long b, long c, long d, long x, long s, long ac) { 145 a += I(b, c, d) + x + ac; 146 a = ((int) a << s) | ((int) a >>> (32 - s)); 147 a += b; 148 return a; 149 } 150 151 /* 152 * md5Update是MD5的主计算过程,inbuf是要变换的字节串,inputlen是长度,这个 153 * 函数由getMD5ofStr调用,调用之前需要调用md5init,因此把它设计成private的 154 */ 155 private void md5Update(byte[] inbuf, int inputLen) { 156 int i, index, partLen; 157 byte[] block = new byte[64]; 158 index = (int) (count[0] >>> 3) & 0x3F; 159 // /* Update number of bits */ 160 if ((count[0] += (inputLen << 3)) < (inputLen << 3)) 161 count[1]++; 162 count[1] += (inputLen >>> 29); 163 partLen = 64 - index; 164 // Transform as many times as possible. 165 if (inputLen >= partLen) { 166 md5Memcpy(buffer, inbuf, index, 0, partLen); 167 md5Transform(buffer); 168 for (i = partLen; i + 63 < inputLen; i += 64) { 169 md5Memcpy(block, inbuf, 0, i, 64); 170 md5Transform(block); 171 } 172 index = 0; 173 } else 174 i = 0; 175 // /* Buffer remaining input */ 176 md5Memcpy(buffer, inbuf, index, i, inputLen - i); 177 } 178 179 /* 180 * md5Final整理和填写输出结果 181 */ 182 private void md5Final() { 183 byte[] bits = new byte[8]; 184 int index, padLen; 185 // /* Save number of bits */ 186 Encode(bits, count, 8); 187 // /* Pad out to 56 mod 64. 188 index = (int) (count[0] >>> 3) & 0x3f; 189 padLen = (index < 56) ? (56 - index) : (120 - index); 190 md5Update(PADDING, padLen); 191 // /* Append length (before padding) */ 192 md5Update(bits, 8); 193 // /* Store state in digest */ 194 Encode(digest, state, 16); 195 } 196 197 /* 198 * 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 199 * 字节拷贝到output的outpos位置开始 200 */ 201 private void md5Memcpy(byte[] output, byte[] input, int outpos, int inpos, 202 int len) { 203 int i; 204 for (i = 0; i < len; i++) 205 output[outpos + i] = input[inpos + i]; 206 } 207 208 /* 209 * md5Transform是MD5核心变换程序,有md5Update调用,block是分块的原始字节 210 */ 211 private void md5Transform(byte block[]) { 212 long a = state[0], b = state[1], c = state[2], d = state[3]; 213 long[] x = new long[16]; 214 Decode(x, block, 64); 215 /* Round 1 */ 216 a = FF(a, b, c, d, x[0], S11, 0xd76aa478L); /* 1 */ 217 d = FF(d, a, b, c, x[1], S12, 0xe8c7b756L); /* 2 */ 218 c = FF(c, d, a, b, x[2], S13, 0x242070dbL); /* 3 */ 219 b = FF(b, c, d, a, x[3], S14, 0xc1bdceeeL); /* 4 */ 220 a = FF(a, b, c, d, x[4], S11, 0xf57c0fafL); /* 5 */ 221 d = FF(d, a, b, c, x[5], S12, 0x4787c62aL); /* 6 */ 222 c = FF(c, d, a, b, x[6], S13, 0xa8304613L); /* 7 */ 223 b = FF(b, c, d, a, x[7], S14, 0xfd469501L); /* 8 */ 224 a = FF(a, b, c, d, x[8], S11, 0x698098d8L); /* 9 */ 225 d = FF(d, a, b, c, x[9], S12, 0x8b44f7afL); /* 10 */ 226 c = FF(c, d, a, b, x[10], S13, 0xffff5bb1L); /* 11 */ 227 b = FF(b, c, d, a, x[11], S14, 0x895cd7beL); /* 12 */ 228 a = FF(a, b, c, d, x[12], S11, 0x6b901122L); /* 13 */ 229 d = FF(d, a, b, c, x[13], S12, 0xfd987193L); /* 14 */ 230 c = FF(c, d, a, b, x[14], S13, 0xa679438eL); /* 15 */ 231 b = FF(b, c, d, a, x[15], S14, 0x49b40821L); /* 16 */ 232 /* Round 2 */ 233 a = GG(a, b, c, d, x[1], S21, 0xf61e2562L); /* 17 */ 234 d = GG(d, a, b, c, x[6], S22, 0xc040b340L); /* 18 */ 235 c = GG(c, d, a, b, x[11], S23, 0x265e5a51L); /* 19 */ 236 b = GG(b, c, d, a, x[0], S24, 0xe9b6c7aaL); /* 20 */ 237 a = GG(a, b, c, d, x[5], S21, 0xd62f105dL); /* 21 */ 238 d = GG(d, a, b, c, x[10], S22, 0x2441453L); /* 22 */ 239 c = GG(c, d, a, b, x[15], S23, 0xd8a1e681L); /* 23 */ 240 b = GG(b, c, d, a, x[4], S24, 0xe7d3fbc8L); /* 24 */ 241 a = GG(a, b, c, d, x[9], S21, 0x21e1cde6L); /* 25 */ 242 d = GG(d, a, b, c, x[14], S22, 0xc33707d6L); /* 26 */ 243 c = GG(c, d, a, b, x[3], S23, 0xf4d50d87L); /* 27 */ 244 b = GG(b, c, d, a, x[8], S24, 0x455a14edL); /* 28 */ 245 a = GG(a, b, c, d, x[13], S21, 0xa9e3e905L); /* 29 */ 246 d = GG(d, a, b, c, x[2], S22, 0xfcefa3f8L); /* 30 */ 247 c = GG(c, d, a, b, x[7], S23, 0x676f02d9L); /* 31 */ 248 b = GG(b, c, d, a, x[12], S24, 0x8d2a4c8aL); /* 32 */ 249 /* Round 3 */ 250 a = HH(a, b, c, d, x[5], S31, 0xfffa3942L); /* 33 */ 251 d = HH(d, a, b, c, x[8], S32, 0x8771f681L); /* 34 */ 252 c = HH(c, d, a, b, x[11], S33, 0x6d9d6122L); /* 35 */ 253 b = HH(b, c, d, a, x[14], S34, 0xfde5380cL); /* 36 */ 254 a = HH(a, b, c, d, x[1], S31, 0xa4beea44L); /* 37 */ 255 d = HH(d, a, b, c, x[4], S32, 0x4bdecfa9L); /* 38 */ 256 c = HH(c, d, a, b, x[7], S33, 0xf6bb4b60L); /* 39 */ 257 b = HH(b, c, d, a, x[10], S34, 0xbebfbc70L); /* 40 */ 258 a = HH(a, b, c, d, x[13], S31, 0x289b7ec6L); /* 41 */ 259 d = HH(d, a, b, c, x[0], S32, 0xeaa127faL); /* 42 */ 260 c = HH(c, d, a, b, x[3], S33, 0xd4ef3085L); /* 43 */ 261 b = HH(b, c, d, a, x[6], S34, 0x4881d05L); /* 44 */ 262 a = HH(a, b, c, d, x[9], S31, 0xd9d4d039L); /* 45 */ 263 d = HH(d, a, b, c, x[12], S32, 0xe6db99e5L); /* 46 */ 264 c = HH(c, d, a, b, x[15], S33, 0x1fa27cf8L); /* 47 */ 265 b = HH(b, c, d, a, x[2], S34, 0xc4ac5665L); /* 48 */ 266 /* Round 4 */ 267 a = II(a, b, c, d, x[0], S41, 0xf4292244L); /* 49 */ 268 d = II(d, a, b, c, x[7], S42, 0x432aff97L); /* 50 */ 269 c = II(c, d, a, b, x[14], S43, 0xab9423a7L); /* 51 */ 270 b = II(b, c, d, a, x[5], S44, 0xfc93a039L); /* 52 */ 271 a = II(a, b, c, d, x[12], S41, 0x655b59c3L); /* 53 */ 272 d = II(d, a, b, c, x[3], S42, 0x8f0ccc92L); /* 54 */ 273 c = II(c, d, a, b, x[10], S43, 0xffeff47dL); /* 55 */ 274 b = II(b, c, d, a, x[1], S44, 0x85845dd1L); /* 56 */ 275 a = II(a, b, c, d, x[8], S41, 0x6fa87e4fL); /* 57 */ 276 d = II(d, a, b, c, x[15], S42, 0xfe2ce6e0L); /* 58 */ 277 c = II(c, d, a, b, x[6], S43, 0xa3014314L); /* 59 */ 278 b = II(b, c, d, a, x[13], S44, 0x4e0811a1L); /* 60 */ 279 a = II(a, b, c, d, x[4], S41, 0xf7537e82L); /* 61 */ 280 d = II(d, a, b, c, x[11], S42, 0xbd3af235L); /* 62 */ 281 c = II(c, d, a, b, x[2], S43, 0x2ad7d2bbL); /* 63 */ 282 b = II(b, c, d, a, x[9], S44, 0xeb86d391L); /* 64 */ 283 state[0] += a; 284 state[1] += b; 285 state[2] += c; 286 state[3] += d; 287 } 288 289 /* 290 * 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 291 */ 292 private void Encode(byte[] output, long[] input, int len) { 293 int i, j; 294 for (i = 0, j = 0; j < len; i++, j += 4) { 295 output[j] = (byte) (input[i] & 0xffL); 296 output[j + 1] = (byte) ((input[i] >>> 8) & 0xffL); 297 output[j + 2] = (byte) ((input[i] >>> 16) & 0xffL); 298 output[j + 3] = (byte) ((input[i] >>> 24) & 0xffL); 299 } 300 } 301 302 /* 303 * Decode把byte数组按顺序合成成long数组,因为java的long类型是64bit的, 304 * 只合成低32bit,高32bit清零,以适应原始C实现的用途 305 */ 306 private void Decode(long[] output, byte[] input, int len) { 307 int i, j; 308 for (i = 0, j = 0; j < len; i++, j += 4) 309 output[i] = b2iu(input[j]) | (b2iu(input[j + 1]) << 8) 310 | (b2iu(input[j + 2]) << 16) | (b2iu(input[j + 3]) << 24); 311 return; 312 } 313 314 /* 315 * 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 316 */ 317 public static long b2iu(byte b) { 318 return b < 0 ? b & 0x7F + 128 : b; 319 } 320 321 /* 322 * byteHEX(),用来把一个byte类型的数转换成十六进制的ASCII表示, 323 * 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) 324 */ 325 public static String byteHEX(byte ib) { 326 char[] Digit = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘, ‘A‘, 327 ‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘F‘ }; 328 char[] ob = new char[2]; 329 ob[0] = Digit[(ib >>> 4) & 0X0F]; 330 ob[1] = Digit[ib & 0X0F]; 331 String s = new String(ob); 332 return s; 333 } 334 } 335