_ Git - BearSSL/blob - src/symcipher/aes_common.c

   1 /*
   2  * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #include "inner.h"
  26
  27 static const uint32_t Rcon[] = {
  28         0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000, 0x20000000,
  29         0x40000000, 0x80000000, 0x1B000000, 0x36000000
  30 };
  31
  32 #define S   br_aes_S
  33
  34 /* see inner.h */
  35 const unsigned char br_aes_S[] = {
  36         0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B,
  37         0xFE, 0xD7, 0xAB, 0x76, 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0,
  38         0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0, 0xB7, 0xFD, 0x93, 0x26,
  39         0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
  40         0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2,
  41         0xEB, 0x27, 0xB2, 0x75, 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0,
  42         0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84, 0x53, 0xD1, 0x00, 0xED,
  43         0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
  44         0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F,
  45         0x50, 0x3C, 0x9F, 0xA8, 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5,
  46         0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2, 0xCD, 0x0C, 0x13, 0xEC,
  47         0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
  48         0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14,
  49         0xDE, 0x5E, 0x0B, 0xDB, 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C,
  50         0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79, 0xE7, 0xC8, 0x37, 0x6D,
  51         0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
  52         0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F,
  53         0x4B, 0xBD, 0x8B, 0x8A, 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E,
  54         0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E, 0xE1, 0xF8, 0x98, 0x11,
  55         0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
  56         0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F,
  57         0xB0, 0x54, 0xBB, 0x16
  58 };
  59
  60 static uint32_t
  61 SubWord(uint32_t x)
  62 {
  63         return ((uint32_t)S[x >> 24] << 24)
  64                 | ((uint32_t)S[(x >> 16) & 0xFF] << 16)
  65                 | ((uint32_t)S[(x >> 8) & 0xFF] << 8)
  66                 | (uint32_t)S[x & 0xFF];
  67 }
  68
  69 /* see inner.h */
  70 unsigned
  71 br_aes_keysched(uint32_t *skey, const void *key, size_t key_len)
  72 {
  73         unsigned num_rounds;
  74         int i, j, k, nk, nkf;
  75
  76         switch (key_len) {
  77         case 16:
  78                 num_rounds = 10;
  79                 break;
  80         case 24:
  81                 num_rounds = 12;
  82                 break;
  83         case 32:
  84                 num_rounds = 14;
  85                 break;
  86         default:
  87                 /* abort(); */
  88                 return 0;
  89         }
  90         nk = (int)(key_len >> 2);
  91         nkf = (int)((num_rounds + 1) << 2);
  92         for (i = 0; i < nk; i ++) {
  93                 skey[i] = br_dec32be((const unsigned char *)key + (i << 2));
  94         }
  95         for (i = nk, j = 0, k = 0; i < nkf; i ++) {
  96                 uint32_t tmp;
  97
  98                 tmp = skey[i - 1];
  99                 if (j == 0) {
 100                         tmp = (tmp << 8) | (tmp >> 24);
 101                         tmp = SubWord(tmp) ^ Rcon[k];
 102                 } else if (nk > 6 && j == 4) {
 103                         tmp = SubWord(tmp);
 104                 }
 105                 skey[i] = skey[i - nk] ^ tmp;
 106                 if (++ j == nk) {
 107                         j = 0;
 108                         k ++;
 109                 }
 110         }
 111         return num_rounds;
 112 }