基于J2ME的MD5算法类代码

//实现MD5算法的类，提供一个静态的函数toMD5()供调用；
//还提供一个getMD5ofStr()函数生成一个MD5加密串；
public class MD5
{
     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 char Hex[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
     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
     };
     private long state[];
     private long count[];
     private byte buffer[];
     public String digestHexStr;
     private byte digest[];
     private byte test;
     public String getMD5ofStr(String s)
     {//返回MD5串；
         int i;
         md5Init();
         md5Update(s.getBytes(), s.length());
         md5Final();
         digestHexStr = "";
         for(i = 0;i<16;i++)
           digestHexStr=digestHexStr+byteHEX(digest[i]);
         return digestHexStr;
     }
     public MD5()
     {
         state = new long[4];
         count = new long[2];
         buffer = new byte[64];
         digest = new byte[16];
         md5Init();
     }
     private void md5Init()
     {//初始化部分变量；
         count[0] = 0L;
         count[1] = 0L;
         state[0] = 0x67452301L;
         state[1] = 0xefcdab89L;
         state[2] = 0x98badcfeL;
         state[3] = 0x10325476L;
     }
     private long F(long l, long l1, long l2)
     {
         return l & l1 | ~l & l2;
     }
     private long G(long l, long l1, long l2)
     {
         return l & l2 | l1 & ~l2;
     }
     private long H(long l, long l1, long l2)
     {
         return l ^ l1 ^ l2;
     }
     private long I(long l, long l1, long l2)
     {
         return l1 ^ (l | ~l2);
     }
     private long FF(long l, long l1, long l2, long l3, long l4, long l5, long l6)
     {
         l += F(l1, l2, l3) + l4 + l6;
         l = (int)l << (int)l5 | (int)l >>> (int)(32L - l5);
         l += l1;
         return l;
     }
     private long GG(long l, long l1, long l2, long l3, long l4, long l5, long l6)
     {
         l += G(l1, l2, l3) + l4 + l6;
         l = (int)l << (int)l5 | (int)l >>> (int)(32L - l5);
         l += l1;
         return l;
     }
     private long HH(long l, long l1, long l2, long l3, long l4, long l5, long l6)
     {
         l += H(l1, l2, l3) + l4 + l6;
         l = (int)l << (int)l5 | (int)l >>> (int)(32L - l5);
         l += l1;
         return l;
     }
     private long II(long l, long l1, long l2, long l3, long l4, long l5, long l6)
     {
         l += I(l1, l2, l3) + l4 + l6;
         l = (int)l << (int)l5 | (int)l >>> (int)(32L - l5);
         l += l1;
         return l;
     }
     private void md5Update(byte abyte0[], int i)
     {//补位操作，abyte0为需要进行MD5加密的字符串，i为字符串长度；
         byte abyte1[] = new byte[64];
         int k = (int)(count[0] >>> 3) & 0x3f;
         if((count[0] += i << 3) < (long)(i << 3))
             count[1]++;
         count[1] += i >>> 29;
         int l = 64 - k;
         int j;
         if(i >= l)
         {
             md5Memcpy(buffer, abyte0, k, 0, l);
             md5Transform(buffer);
             for(j = l; j + 63 < i; j += 64)
             {
                 md5Memcpy(abyte1, abyte0, 0, j, 64);
                 md5Transform(abyte1);
             }
             k = 0;
         } else
         {
             j = 0;
         }
         md5Memcpy(buffer, abyte0, k, j, i - j);
     }
     private void md5Final()
     {//最终处理，将得到的128位（16字节）MD5码存放在digest数组中
         byte abyte0[] = new byte[8];
         Encode(abyte0, count, 8);
         int i = (int)(count[0] >>> 3) & 0x3f;
         int j = i >= 56 ? 120 - i : 56 - i;
         md5Update(PADDING, j);
         md5Update(abyte0, 8);
         Encode(digest, state, 16);
     }
     private void md5Memcpy(byte abyte0[], byte abyte1[], int i, int j, int k)
     {
         for(int l = 0; l < k; l++)
             abyte0[i + l] = abyte1[j + l];
     }
     private void md5Transform(byte abyte0[])
     {
         long l = state[0];
         long l1 = state[1];
         long l2 = state[2];
         long l3 = state[3];
         long al[] = new long[16];
         Decode(al, abyte0, 64);
         l = FF(l, l1, l2, l3, al[0], 7L, 0xd76aa478L);
         l3 = FF(l3, l, l1, l2, al[1], 12L, 0xe8c7b756L);
         l2 = FF(l2, l3, l, l1, al[2], 17L, 0x242070dbL);
         l1 = FF(l1, l2, l3, l, al[3], 22L, 0xc1bdceeeL);
         l = FF(l, l1, l2, l3, al[4], 7L, 0xf57c0fafL);
         l3 = FF(l3, l, l1, l2, al[5], 12L, 0x4787c62aL);
         l2 = FF(l2, l3, l, l1, al[6], 17L, 0xa8304613L);
         l1 = FF(l1, l2, l3, l, al[7], 22L, 0xfd469501L);
         l = FF(l, l1, l2, l3, al[8], 7L, 0x698098d8L);
         l3 = FF(l3, l, l1, l2, al[9], 12L, 0x8b44f7afL);
         l2 = FF(l2, l3, l, l1, al[10], 17L, 0xffff5bb1L);
         l1 = FF(l1, l2, l3, l, al[11], 22L, 0x895cd7beL);
         l = FF(l, l1, l2, l3, al[12], 7L, 0x6b901122L);
         l3 = FF(l3, l, l1, l2, al[13], 12L, 0xfd987193L);
         l2 = FF(l2, l3, l, l1, al[14], 17L, 0xa679438eL);
         l1 = FF(l1, l2, l3, l, al[15], 22L, 0x49b40821L);
         l = GG(l, l1, l2, l3, al[1], 5L, 0xf61e2562L);
         l3 = GG(l3, l, l1, l2, al[6], 9L, 0xc040b340L);
         l2 = GG(l2, l3, l, l1, al[11], 14L, 0x265e5a51L);
         l1 = GG(l1, l2, l3, l, al[0], 20L, 0xe9b6c7aaL);
         l = GG(l, l1, l2, l3, al[5], 5L, 0xd62f105dL);
         l3 = GG(l3, l, l1, l2, al[10], 9L, 0x2441453L);
         l2 = GG(l2, l3, l, l1, al[15], 14L, 0xd8a1e681L);
         l1 = GG(l1, l2, l3, l, al[4], 20L, 0xe7d3fbc8L);
         l = GG(l, l1, l2, l3, al[9], 5L, 0x21e1cde6L);
         l3 = GG(l3, l, l1, l2, al[14], 9L, 0xc33707d6L);
         l2 = GG(l2, l3, l, l1, al[3], 14L, 0xf4d50d87L);
         l1 = GG(l1, l2, l3, l, al[8], 20L, 0x455a14edL);
         l = GG(l, l1, l2, l3, al[13], 5L, 0xa9e3e905L);
         l3 = GG(l3, l, l1, l2, al[2], 9L, 0xfcefa3f8L);
         l2 = GG(l2, l3, l, l1, al[7], 14L, 0x676f02d9L);
         l1 = GG(l1, l2, l3, l, al[12], 20L, 0x8d2a4c8aL);
         l = HH(l, l1, l2, l3, al[5], 4L, 0xfffa3942L);
         l3 = HH(l3, l, l1, l2, al[8], 11L, 0x8771f681L);
         l2 = HH(l2, l3, l, l1, al[11], 16L, 0x6d9d6122L);
         l1 = HH(l1, l2, l3, l, al[14], 23L, 0xfde5380cL);
         l = HH(l, l1, l2, l3, al[1], 4L, 0xa4beea44L);
         l3 = HH(l3, l, l1, l2, al[4], 11L, 0x4bdecfa9L);
         l2 = HH(l2, l3, l, l1, al[7], 16L, 0xf6bb4b60L);
         l1 = HH(l1, l2, l3, l, al[10], 23L, 0xbebfbc70L);
         l = HH(l, l1, l2, l3, al[13], 4L, 0x289b7ec6L);
         l3 = HH(l3, l, l1, l2, al[0], 11L, 0xeaa127faL);
         l2 = HH(l2, l3, l, l1, al[3], 16L, 0xd4ef3085L);
         l1 = HH(l1, l2, l3, l, al[6], 23L, 0x4881d05L);
         l = HH(l, l1, l2, l3, al[9], 4L, 0xd9d4d039L);
         l3 = HH(l3, l, l1, l2, al[12], 11L, 0xe6db99e5L);
         l2 = HH(l2, l3, l, l1, al[15], 16L, 0x1fa27cf8L);
         l1 = HH(l1, l2, l3, l, al[2], 23L, 0xc4ac5665L);
         l = II(l, l1, l2, l3, al[0], 6L, 0xf4292244L);
         l3 = II(l3, l, l1, l2, al[7], 10L, 0x432aff97L);
         l2 = II(l2, l3, l, l1, al[14], 15L, 0xab9423a7L);
         l1 = II(l1, l2, l3, l, al[5], 21L, 0xfc93a039L);
         l = II(l, l1, l2, l3, al[12], 6L, 0x655b59c3L);
         l3 = II(l3, l, l1, l2, al[3], 10L, 0x8f0ccc92L);
         l2 = II(l2, l3, l, l1, al[10], 15L, 0xffeff47dL);
         l1 = II(l1, l2, l3, l, al[1], 21L, 0x85845dd1L);
         l = II(l, l1, l2, l3, al[8], 6L, 0x6fa87e4fL);
         l3 = II(l3, l, l1, l2, al[15], 10L, 0xfe2ce6e0L);
         l2 = II(l2, l3, l, l1, al[6], 15L, 0xa3014314L);
         l1 = II(l1, l2, l3, l, al[13], 21L, 0x4e0811a1L);
         l = II(l, l1, l2, l3, al[4], 6L, 0xf7537e82L);
         l3 = II(l3, l, l1, l2, al[11], 10L, 0xbd3af235L);
         l2 = II(l2, l3, l, l1, al[2], 15L, 0x2ad7d2bbL);
         l1 = II(l1, l2, l3, l, al[9], 21L, 0xeb86d391L);
         state[0] += l;
         state[1] += l1;
         state[2] += l2;
         state[3] += l3;
     }
     private void Encode(byte abyte0[], long al[], int i)
     {//转换函数，将al中long型的变量输出到byte型的数组abyte0中，
      //低位字节在前，高位字节在后；
         int j = 0;
         for(int k = 0; k < i; k += 4)
         {
             abyte0[k] = (byte)(int)(al[j] & 255L);
             abyte0[k + 1] = (byte)(int)(al[j] >>> 8 & 255L);
             abyte0[k + 2] = (byte)(int)(al[j] >>> 16 & 255L);
             abyte0[k + 3] = (byte)(int)(al[j] >>> 24 & 255L);
             j++;
         }
     }
     private void Decode(long al[], byte abyte0[], int i)
     {
         int j = 0;
         for(int k = 0; k < i; k += 4)
         {
             al[j] = b2iu(abyte0[k]) | b2iu(abyte0[k + 1]) << 8 | b2iu(abyte0[k + 2]) << 16 | b2iu(abyte0[k + 3]) << 24;
             j++;
         }
     }
     public static long b2iu(byte byte0)
     {
         return byte0 >= 0 ? byte0 : byte0 & 0xff;
     }
     public static String byteHEX(byte byte0)
     {//字节到十六进制的ASCII码转换
         char ac[] = {
             '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
             'A', 'B', 'C', 'D', 'E', 'F'
         };
         char ac1[] = new char[2];
         ac1[0] = ac[byte0 >>> 4 & 0xf];
         ac1[1] = ac[byte0 & 0xf];
         String s = new String(ac1);
         return s;
     }
     public static String toMD5(String s)
     {
         MD5 md5 = new MD5();
         return md5.getMD5ofStr(s);
     }
}

 

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