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 #define S br_aes_S 28 29 static void 30 add_round_key(unsigned *state, const uint32_t *skeys) 31 { 32 int i; 33 34 for (i = 0; i < 16; i += 4) { 35 uint32_t k; 36 37 k = *skeys ++; 38 state[i + 0] ^= (unsigned)(k >> 24); 39 state[i + 1] ^= (unsigned)(k >> 16) & 0xFF; 40 state[i + 2] ^= (unsigned)(k >> 8) & 0xFF; 41 state[i + 3] ^= (unsigned)k & 0xFF; 42 } 43 } 44 45 static void 46 sub_bytes(unsigned *state) 47 { 48 int i; 49 50 for (i = 0; i < 16; i ++) { 51 state[i] = S[state[i]]; 52 } 53 } 54 55 static void 56 shift_rows(unsigned *state) 57 { 58 unsigned tmp; 59 60 tmp = state[1]; 61 state[1] = state[5]; 62 state[5] = state[9]; 63 state[9] = state[13]; 64 state[13] = tmp; 65 66 tmp = state[2]; 67 state[2] = state[10]; 68 state[10] = tmp; 69 tmp = state[6]; 70 state[6] = state[14]; 71 state[14] = tmp; 72 73 tmp = state[15]; 74 state[15] = state[11]; 75 state[11] = state[7]; 76 state[7] = state[3]; 77 state[3] = tmp; 78 } 79 80 static void 81 mix_columns(unsigned *state) 82 { 83 int i; 84 85 for (i = 0; i < 16; i += 4) { 86 unsigned s0, s1, s2, s3; 87 unsigned t0, t1, t2, t3; 88 89 s0 = state[i + 0]; 90 s1 = state[i + 1]; 91 s2 = state[i + 2]; 92 s3 = state[i + 3]; 93 t0 = (s0 << 1) ^ s1 ^ (s1 << 1) ^ s2 ^ s3; 94 t1 = s0 ^ (s1 << 1) ^ s2 ^ (s2 << 1) ^ s3; 95 t2 = s0 ^ s1 ^ (s2 << 1) ^ s3 ^ (s3 << 1); 96 t3 = s0 ^ (s0 << 1) ^ s1 ^ s2 ^ (s3 << 1); 97 state[i + 0] = t0 ^ ((unsigned)(-(int)(t0 >> 8)) & 0x11B); 98 state[i + 1] = t1 ^ ((unsigned)(-(int)(t1 >> 8)) & 0x11B); 99 state[i + 2] = t2 ^ ((unsigned)(-(int)(t2 >> 8)) & 0x11B); 100 state[i + 3] = t3 ^ ((unsigned)(-(int)(t3 >> 8)) & 0x11B); 101 } 102 } 103 104 /* see inner.h */ 105 void 106 br_aes_small_encrypt(unsigned num_rounds, const uint32_t *skey, void *data) 107 { 108 unsigned char *buf; 109 unsigned state[16]; 110 unsigned u; 111 112 buf = data; 113 for (u = 0; u < 16; u ++) { 114 state[u] = buf[u]; 115 } 116 add_round_key(state, skey); 117 for (u = 1; u < num_rounds; u ++) { 118 sub_bytes(state); 119 shift_rows(state); 120 mix_columns(state); 121 add_round_key(state, skey + (u << 2)); 122 } 123 sub_bytes(state); 124 shift_rows(state); 125 add_round_key(state, skey + (num_rounds << 2)); 126 for (u = 0; u < 16; u ++) { 127 buf[u] = state[u]; 128 } 129 } 130