diff options
Diffstat (limited to 'contrib/bearssl/src/symcipher/aes_small_enc.c')
-rw-r--r-- | contrib/bearssl/src/symcipher/aes_small_enc.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/contrib/bearssl/src/symcipher/aes_small_enc.c b/contrib/bearssl/src/symcipher/aes_small_enc.c new file mode 100644 index 000000000000..29f48a8f4f6e --- /dev/null +++ b/contrib/bearssl/src/symcipher/aes_small_enc.c @@ -0,0 +1,129 @@ +/* + * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include "inner.h" + +#define S br_aes_S + +static void +add_round_key(unsigned *state, const uint32_t *skeys) +{ + int i; + + for (i = 0; i < 16; i += 4) { + uint32_t k; + + k = *skeys ++; + state[i + 0] ^= (unsigned)(k >> 24); + state[i + 1] ^= (unsigned)(k >> 16) & 0xFF; + state[i + 2] ^= (unsigned)(k >> 8) & 0xFF; + state[i + 3] ^= (unsigned)k & 0xFF; + } +} + +static void +sub_bytes(unsigned *state) +{ + int i; + + for (i = 0; i < 16; i ++) { + state[i] = S[state[i]]; + } +} + +static void +shift_rows(unsigned *state) +{ + unsigned tmp; + + tmp = state[1]; + state[1] = state[5]; + state[5] = state[9]; + state[9] = state[13]; + state[13] = tmp; + + tmp = state[2]; + state[2] = state[10]; + state[10] = tmp; + tmp = state[6]; + state[6] = state[14]; + state[14] = tmp; + + tmp = state[15]; + state[15] = state[11]; + state[11] = state[7]; + state[7] = state[3]; + state[3] = tmp; +} + +static void +mix_columns(unsigned *state) +{ + int i; + + for (i = 0; i < 16; i += 4) { + unsigned s0, s1, s2, s3; + unsigned t0, t1, t2, t3; + + s0 = state[i + 0]; + s1 = state[i + 1]; + s2 = state[i + 2]; + s3 = state[i + 3]; + t0 = (s0 << 1) ^ s1 ^ (s1 << 1) ^ s2 ^ s3; + t1 = s0 ^ (s1 << 1) ^ s2 ^ (s2 << 1) ^ s3; + t2 = s0 ^ s1 ^ (s2 << 1) ^ s3 ^ (s3 << 1); + t3 = s0 ^ (s0 << 1) ^ s1 ^ s2 ^ (s3 << 1); + state[i + 0] = t0 ^ ((unsigned)(-(int)(t0 >> 8)) & 0x11B); + state[i + 1] = t1 ^ ((unsigned)(-(int)(t1 >> 8)) & 0x11B); + state[i + 2] = t2 ^ ((unsigned)(-(int)(t2 >> 8)) & 0x11B); + state[i + 3] = t3 ^ ((unsigned)(-(int)(t3 >> 8)) & 0x11B); + } +} + +/* see inner.h */ +void +br_aes_small_encrypt(unsigned num_rounds, const uint32_t *skey, void *data) +{ + unsigned char *buf; + unsigned state[16]; + unsigned u; + + buf = data; + for (u = 0; u < 16; u ++) { + state[u] = buf[u]; + } + add_round_key(state, skey); + for (u = 1; u < num_rounds; u ++) { + sub_bytes(state); + shift_rows(state); + mix_columns(state); + add_round_key(state, skey + (u << 2)); + } + sub_bytes(state); + shift_rows(state); + add_round_key(state, skey + (num_rounds << 2)); + for (u = 0; u < 16; u ++) { + buf[u] = state[u]; + } +} |