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是一個內部使用的byte數組的塊拷貝函數，從input的inpos開始把len長度的　　　　　 字節拷貝到output的outpos位置開始        */        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核心變換程序，有md5Update調用，block是分塊的原始字節        */        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數組按順序拆成byte數組，因為java的long類型是64bit的，          只拆低32bit，以適應原始C實現的用途        */        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數組按順序合成成long數組，因為java的long類型是64bit的，          只合成低32bit，高32bit清零，以適應原始C實現的用途        */        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是我寫的一個把byte按照不考慮正負號的原則的＂升位＂程序，因為java沒有unsigned運算        */        public static long b2iu(byte b) {                return b < 0 ? b & 0x7F + 128 : b;        }	/*byteHEX()，用來把一個byte類型的數轉換成十六進制的ASCII表示，	　因為java中的byte的toString無法實現這一點，我們又沒有C語言中的	  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) {   //如果沒有參數，執行標準的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]));        }}