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MD5 算法的Java Bean


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#1 Tanya

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发表于 2006/05/10 21:51:28

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,我们把它们
	   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的
		*/
		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, 8);

				///* 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, 8);

				///* 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] >>> 8) & 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]) << 8) |
								(b2iu(input[j + 2]) << 16) |
								(b2iu(input[j + 3]) << 24);

				return;
		}
	   
		/*
		  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
		*/
		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) {
				char[] Digit = { '0','1','2','3','4','5','6','7','8','9',
				'A','B','C','D','E','F' };
				char [] ob = new char[2];
				ob[0] = Digit[(ib >>> 4) & 0X0F];
				ob[1] = Digit[ib & 0X0F];
				String s = new String(ob);
				return s;
		}

		public static void main(String args[]) {


				MD5 m = new MD5();
				if (Array.getLength(args) == 0) {   //如果没有参数,执行标准的Test Suite
				
						   System.out.println("MD5 Test suite:");
					System.out.println("MD5(\"\"):"+m.getMD5ofStr(""));
					System.out.println("MD5(\"a\"):"+m.getMD5ofStr("a"));
					System.out.println("MD5(\"abc\"):"+m.getMD5ofStr("abc"));
					System.out.println("MD5(\"message digest\"):"+m.getMD5ofStr("message digest"));
					System.out.println("MD5(\"abcdefghijklmnopqrstuvwxyz\"):"+
						m.getMD5ofStr("abcdefghijklmnopqrstuvwxyz"));
					System.out.println("MD5(\"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789\"):"+
						 m.getMD5ofStr("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"));
				}
				else 
						  System.out.println("MD5(" + args[0] + ")=" + m.getMD5ofStr(args[0]));
				
		 
		}

}