/* * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at> * * some optimization ideas from aes128.c by Reimar Doeffinger * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "common.h" #include "aes.h" #include "intreadwrite.h" typedef union { uint64_t u64[2]; uint32_t u32[4]; uint8_t u8x4[4][4]; uint8_t u8[16]; } av_aes_block; typedef struct AVAES { // Note: round_key[16] is accessed in the init code, but this only // overwrites state, which does not matter (see also commit ba554c0). av_aes_block round_key[15]; av_aes_block state[2]; int rounds; } AVAES; const int av_aes_size= sizeof(AVAES); static const uint8_t rcon[10] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 }; static uint8_t sbox[256]; static uint8_t inv_sbox[256]; #if CONFIG_SMALL static uint32_t enc_multbl[1][256]; static uint32_t dec_multbl[1][256]; #else static uint32_t enc_multbl[4][256]; static uint32_t dec_multbl[4][256]; #endif #if HAVE_BIGENDIAN # define ROT(x, s) ((x >> s) | (x << (32-s))) #else # define ROT(x, s) ((x << s) | (x >> (32-s))) #endif static inline void addkey(av_aes_block *dst, const av_aes_block *src, const av_aes_block *round_key) { dst->u64[0] = src->u64[0] ^ round_key->u64[0]; dst->u64[1] = src->u64[1] ^ round_key->u64[1]; } static inline void addkey_s(av_aes_block *dst, const uint8_t *src, const av_aes_block *round_key) { dst->u64[0] = AV_RN64(src) ^ round_key->u64[0]; dst->u64[1] = AV_RN64(src + 8) ^ round_key->u64[1]; } static inline void addkey_d(uint8_t *dst, const av_aes_block *src, const av_aes_block *round_key) { AV_WN64(dst, src->u64[0] ^ round_key->u64[0]); AV_WN64(dst + 8, src->u64[1] ^ round_key->u64[1]); } static void subshift(av_aes_block s0[2], int s, const uint8_t *box) { av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s); av_aes_block *s3 = (av_aes_block *) (s0[0].u8 + s); s0[0].u8[ 0] = box[s0[1].u8[ 0]]; s0[0].u8[ 4] = box[s0[1].u8[ 4]]; s0[0].u8[ 8] = box[s0[1].u8[ 8]]; s0[0].u8[12] = box[s0[1].u8[12]]; s1[0].u8[ 3] = box[s1[1].u8[ 7]]; s1[0].u8[ 7] = box[s1[1].u8[11]]; s1[0].u8[11] = box[s1[1].u8[15]]; s1[0].u8[15] = box[s1[1].u8[ 3]]; s0[0].u8[ 2] = box[s0[1].u8[10]]; s0[0].u8[10] = box[s0[1].u8[ 2]]; s0[0].u8[ 6] = box[s0[1].u8[14]]; s0[0].u8[14] = box[s0[1].u8[ 6]]; s3[0].u8[ 1] = box[s3[1].u8[13]]; s3[0].u8[13] = box[s3[1].u8[ 9]]; s3[0].u8[ 9] = box[s3[1].u8[ 5]]; s3[0].u8[ 5] = box[s3[1].u8[ 1]]; } static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){ #if CONFIG_SMALL return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24); #else return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d]; #endif } static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3){ uint8_t (*src)[4] = state[1].u8x4; state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]); state[0].u32[1] = mix_core(multbl, src[1][0], src[s3-1][1], src[3][2], src[s1-1][3]); state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]); state[0].u32[3] = mix_core(multbl, src[3][0], src[s1-1][1], src[1][2], src[s3-1][3]); } static inline void crypt(AVAES *a, int s, const uint8_t *sbox, uint32_t multbl[][256]) { int r; for (r = a->rounds - 1; r > 0; r--) { mix(a->state, multbl, 3 - s, 1 + s); addkey(&a->state[1], &a->state[0], &a->round_key[r]); } subshift(&a->state[0], s, sbox); } void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt) { while (count--) { addkey_s(&a->state[1], src, &a->round_key[a->rounds]); if (decrypt) { crypt(a, 0, inv_sbox, dec_multbl); if (iv) { addkey_s(&a->state[0], iv, &a->state[0]); memcpy(iv, src, 16); } addkey_d(dst, &a->state[0], &a->round_key[0]); } else { if (iv) addkey_s(&a->state[1], iv, &a->state[1]); crypt(a, 2, sbox, enc_multbl); addkey_d(dst, &a->state[0], &a->round_key[0]); if (iv) memcpy(iv, dst, 16); } src += 16; dst += 16; } } static void init_multbl2(uint32_t tbl[][256], const int c[4], const uint8_t *log8, const uint8_t *alog8, const uint8_t *sbox) { int i; for (i = 0; i < 256; i++) { int x = sbox[i]; if (x) { int k, l, m, n; x = log8[x]; k = alog8[x + log8[c[0]]]; l = alog8[x + log8[c[1]]]; m = alog8[x + log8[c[2]]]; n = alog8[x + log8[c[3]]]; tbl[0][i] = AV_NE(MKBETAG(k,l,m,n), MKTAG(k,l,m,n)); #if !CONFIG_SMALL tbl[1][i] = ROT(tbl[0][i], 8); tbl[2][i] = ROT(tbl[0][i], 16); tbl[3][i] = ROT(tbl[0][i], 24); #endif } } } // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt) { int i, j, t, rconpointer = 0; uint8_t tk[8][4]; int KC = key_bits >> 5; int rounds = KC + 6; uint8_t log8[256]; uint8_t alog8[512]; if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]) { j = 1; for (i = 0; i < 255; i++) { alog8[i] = alog8[i + 255] = j; log8[j] = i; j ^= j + j; if (j > 255) j ^= 0x11B; } for (i = 0; i < 256; i++) { j = i ? alog8[255 - log8[i]] : 0; j ^= (j << 1) ^ (j << 2) ^ (j << 3) ^ (j << 4); j = (j ^ (j >> 8) ^ 99) & 255; inv_sbox[j] = i; sbox[i] = j; } init_multbl2(dec_multbl, (const int[4]) { 0xe, 0x9, 0xd, 0xb }, log8, alog8, inv_sbox); init_multbl2(enc_multbl, (const int[4]) { 0x2, 0x1, 0x1, 0x3 }, log8, alog8, sbox); } if (key_bits != 128 && key_bits != 192 && key_bits != 256) return -1; a->rounds = rounds; memcpy(tk, key, KC * 4); memcpy(a->round_key[0].u8, key, KC * 4); for (t = KC * 4; t < (rounds + 1) * 16; t += KC * 4) { for (i = 0; i < 4; i++) tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]]; tk[0][0] ^= rcon[rconpointer++]; for (j = 1; j < KC; j++) { if (KC != 8 || j != KC >> 1) for (i = 0; i < 4; i++) tk[j][i] ^= tk[j - 1][i]; else for (i = 0; i < 4; i++) tk[j][i] ^= sbox[tk[j - 1][i]]; } memcpy(a->round_key[0].u8 + t, tk, KC * 4); } if (decrypt) { for (i = 1; i < rounds; i++) { av_aes_block tmp[3]; tmp[2] = a->round_key[i]; subshift(&tmp[1], 0, sbox); mix(tmp, dec_multbl, 1, 3); a->round_key[i] = tmp[0]; } } else { for (i = 0; i < (rounds + 1) >> 1; i++) { FFSWAP(av_aes_block, a->round_key[i], a->round_key[rounds-i]); } } return 0; } #ifdef TEST // LCOV_EXCL_START #include <string.h> #include "lfg.h" #include "log.h" int main(int argc, char **argv) { int i, j; AVAES b; uint8_t rkey[2][16] = { { 0 }, { 0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59 } }; uint8_t pt[16], rpt[2][16]= { { 0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3 }, { 0 } }; uint8_t rct[2][16]= { { 0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf }, { 0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65 } }; uint8_t temp[16]; int err = 0; av_log_set_level(AV_LOG_DEBUG); for (i = 0; i < 2; i++) { av_aes_init(&b, rkey[i], 128, 1); av_aes_crypt(&b, temp, rct[i], 1, NULL, 1); for (j = 0; j < 16; j++) { if (rpt[i][j] != temp[j]) { av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], temp[j]); err = 1; } } } if (argc > 1 && !strcmp(argv[1], "-t")) { AVAES ae, ad; AVLFG prng; av_aes_init(&ae, "PI=3.141592654..", 128, 0); av_aes_init(&ad, "PI=3.141592654..", 128, 1); av_lfg_init(&prng, 1); for (i = 0; i < 10000; i++) { for (j = 0; j < 16; j++) { pt[j] = av_lfg_get(&prng); } { START_TIMER; av_aes_crypt(&ae, temp, pt, 1, NULL, 0); if (!(i & (i - 1))) av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", temp[0], temp[5], temp[10], temp[15]); av_aes_crypt(&ad, temp, temp, 1, NULL, 1); STOP_TIMER("aes"); } for (j = 0; j < 16; j++) { if (pt[j] != temp[j]) { av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i, j, pt[j], temp[j]); } } } } return err; } // LCOV_EXCL_STOP #endif