source/maths/MD5.cpp

   1 /* Copyright (C) 2010 Wildfire Games.
   2  * This file is part of 0 A.D.
   3  *
   4  * 0 A.D. is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * 0 A.D. is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "precompiled.h"
  19
  20 // Based on md5.cpp from Crypto++ 5.6.0:
  21 //   "md5.cpp - modified by Wei Dai from Colin Plumb's public domain md5.c"
  22 //   "any modifications are placed in the public domain"
  23
  24 #include "MD5.h"
  25
  26 MD5::MD5()
  27 {
  28         InitState();
  29 }
  30
  31 void MD5::InitState()
  32 {
  33         m_Digest[0] = 0x67452301L;
  34         m_Digest[1] = 0xefcdab89L;
  35         m_Digest[2] = 0x98badcfeL;
  36         m_Digest[3] = 0x10325476L;
  37         m_BufLen = 0;
  38         m_InputLen = 0;
  39         memset(m_Buf, 0xcc, sizeof(m_Buf));
  40 }
  41
  42 void MD5::UpdateRest(const u8* data, size_t len)
  43 {
  44         const size_t CHUNK_SIZE = sizeof(m_Buf);
  45
  46         // Add as much data as possible to the buffer
  47         size_t n = CHUNK_SIZE - m_BufLen;
  48 //      ENSURE(len >= n);
  49         memcpy(m_Buf + m_BufLen, data, n);
  50         data += n;
  51         len -= n;
  52
  53         // Flush the (now full) buffer
  54         Transform((const u32*)m_Buf); // assumes little-endian
  55
  56         // Process whole chunks of the input
  57         while (len >= CHUNK_SIZE)
  58         {
  59                 Transform((const u32*)data); // assumes little-endian; ignores alignment
  60                 data += CHUNK_SIZE;
  61                 len -= CHUNK_SIZE;
  62         }
  63
  64         // Add the remainder to the buffer
  65         memcpy(m_Buf, data, len);
  66         m_BufLen = len;
  67 }
  68
  69 void MD5::Final(u8* digest)
  70 {
  71         // Compute the message length in bits (before padding)
  72         u64 len = m_InputLen * 8;
  73
  74         // Pad with 1-bit
  75         const u8 pad = 0x80;
  76         Update(&pad, 1);
  77
  78         // Fill with zeros until length % 64 = 56 (bytes)
  79         while (m_BufLen % 64 != 56)
  80         {
  81                 const u8 zero = 0;
  82                 Update(&zero, 1);
  83         }
  84
  85         // Append the length (assumes little-endian)
  86         Update((const u8*)&len, 8);
  87
  88         // Return the digest (assumes little-endian)
  89         memcpy(digest, m_Digest, DIGESTSIZE);
  90
  91         // Reset
  92         InitState();
  93 }
  94
  95 // Use macro rather than inline function for significantly better debug-mode performance
  96 #define rotlFixed(x, y) (((x) << (y)) | ((x) >> (32 - (y))))
  97 // TODO: Crypto++ has an overload using _lrotl on MSVC - is that worthwhile?
  98
  99 void MD5::Transform(const u32* in)
 100 {
 101 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 102 #define F2(x, y, z) F1(z, x, y)
 103 #define F3(x, y, z) (x ^ y ^ z)
 104 #define F4(x, y, z) (y ^ (x | ~z))
 105
 106 #define MD5STEP(f, w, x, y, z, data, s) \
 107         t = w + f(x, y, z) + data; w = rotlFixed(t, s) + x
 108
 109         u32* digest = m_Digest;
 110
 111         u32 a, b, c, d;
 112         u32 t;
 113
 114         a = digest[0];
 115         b = digest[1];
 116         c = digest[2];
 117         d = digest[3];
 118
 119         MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 120         MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 121         MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 122         MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 123         MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 124         MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 125         MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 126         MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 127         MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 128         MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 129         MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 130         MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 131         MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 132         MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 133         MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 134         MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 135
 136         MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 137         MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 138         MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 139         MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 140         MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 141         MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 142         MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 143         MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 144         MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 145         MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 146         MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 147         MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 148         MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 149         MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 150         MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 151         MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 152
 153         MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 154         MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 155         MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 156         MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 157         MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 158         MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 159         MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 160         MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 161         MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 162         MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 163         MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 164         MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 165         MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 166         MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 167         MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 168         MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 169
 170         MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 171         MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 172         MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 173         MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 174         MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 175         MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 176         MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 177         MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 178         MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 179         MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 180         MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 181         MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 182         MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 183         MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 184         MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 185         MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 186
 187         digest[0] += a;
 188         digest[1] += b;
 189         digest[2] += c;
 190         digest[3] += d;
 191 }