mcs/class/referencesource/System.Workflow.Runtime/MD5HashHelper.cs

   1 //------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //------------------------------------------------------------
   4
   5 namespace System.Workflow.Runtime
   6 {
   7     static class MD5HashHelper
   8     {
   9         // "derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm"
  10         // DO NOT USE FOR SECURITY PURPOSES.
  11         public static byte[] ComputeHash(byte[] buffer)
  12         {
  13             int[] shifts = new int[] { 7, 12, 17, 22, 5, 9, 14, 20, 4, 11, 16, 23, 6, 10, 15, 21 };
  14             uint[] sines = new uint[] {
  15                 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
  16                 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
  17
  18                 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
  19                 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
  20
  21                 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
  22                 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
  23
  24                 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
  25                 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 };
  26
  27             int blocks = (buffer.Length + 8) / 64 + 1;
  28
  29             uint aa = 0x67452301;
  30             uint bb = 0xefcdab89;
  31             uint cc = 0x98badcfe;
  32             uint dd = 0x10325476;
  33
  34             for (int i = 0; i < blocks; i++)
  35             {
  36                 byte[] block = buffer;
  37                 int offset = i * 64;
  38
  39                 if (offset + 64 > buffer.Length)
  40                 {
  41                     block = new byte[64];
  42
  43                     for (int j = offset; j < buffer.Length; j++)
  44                     {
  45                         block[j - offset] = buffer[j];
  46                     }
  47                     if (offset <= buffer.Length)
  48                     {
  49                         block[buffer.Length - offset] = 0x80;
  50                     }
  51                     if (i == blocks - 1)
  52                     {
  53                         block[56] = (byte)(buffer.Length << 3);
  54                         block[57] = (byte)(buffer.Length >> 5);
  55                         block[58] = (byte)(buffer.Length >> 13);
  56                         block[59] = (byte)(buffer.Length >> 21);
  57                     }
  58
  59                     offset = 0;
  60                 }
  61
  62                 uint a = aa;
  63                 uint b = bb;
  64                 uint c = cc;
  65                 uint d = dd;
  66
  67                 uint f;
  68                 int g;
  69
  70                 for (int j = 0; j < 64; j++)
  71                 {
  72                     if (j < 16)
  73                     {
  74                         f = b & c | ~b & d;
  75                         g = j;
  76                     }
  77                     else if (j < 32)
  78                     {
  79                         f = b & d | c & ~d;
  80                         g = 5 * j + 1;
  81                     }
  82                     else if (j < 48)
  83                     {
  84                         f = b ^ c ^ d;
  85                         g = 3 * j + 5;
  86                     }
  87                     else
  88                     {
  89                         f = c ^ (b | ~d);
  90                         g = 7 * j;
  91                     }
  92
  93                     g = (g & 0x0f) * 4 + offset;
  94
  95                     uint hold = d;
  96                     d = c;
  97                     c = b;
  98
  99                     b = a + f + sines[j] + (uint)(block[g] + (block[g + 1] << 8) + (block[g + 2] << 16) + (block[g + 3] << 24));
 100                     b = b << shifts[j & 3 | j >> 2 & ~3] | b >> 32 - shifts[j & 3 | j >> 2 & ~3];
 101                     b += c;
 102
 103                     a = hold;
 104                 }
 105
 106                 aa += a;
 107                 bb += b;
 108                 cc += c;
 109                 dd += d;
 110             }
 111
 112             return new byte[] {
 113                 (byte)aa, (byte)(aa >> 8), (byte)(aa >> 16), (byte)(aa >> 24),
 114                 (byte)bb, (byte)(bb >> 8), (byte)(bb >> 16), (byte)(bb >> 24),
 115                 (byte)cc, (byte)(cc >> 8), (byte)(cc >> 16), (byte)(cc >> 24),
 116                 (byte)dd, (byte)(dd >> 8), (byte)(dd >> 16), (byte)(dd >> 24) };
 117         }
 118     }
 119 }