Java MD5加密类

  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 }