2 * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 uint8_t round_key[15][4][4];
31 static const uint8_t rcon[30] = {
32 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80,
33 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f,
34 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4,
35 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91
38 static uint8_t sbox[256];
39 static uint8_t inv_sbox[256];
41 static uint32_t enc_multbl[1][256];
42 static uint32_t dec_multbl[1][256];
44 static uint32_t enc_multbl[4][256];
45 static uint32_t dec_multbl[4][256];
48 static inline void addkey(uint64_t state[2], uint64_t round_key[2]){
49 state[0] ^= round_key[0];
50 state[1] ^= round_key[1];
53 #define SUBSHIFT0(s, box) s[0]=box[s[ 0]]; s[ 4]=box[s[ 4]]; s[ 8]=box[s[ 8]]; s[12]=box[s[12]];
54 #define SUBSHIFT1(s, box) t=s[0]; s[0]=box[s[ 4]]; s[ 4]=box[s[ 8]]; s[ 8]=box[s[12]]; s[12]=box[t];
55 #define SUBSHIFT2(s, box) t=s[0]; s[0]=box[s[ 8]]; s[ 8]=box[ t]; t=s[ 4]; s[ 4]=box[s[12]]; s[12]=box[t];
56 #define SUBSHIFT3(s, box) t=s[0]; s[0]=box[s[12]]; s[12]=box[s[ 8]]; s[ 8]=box[s[ 4]]; s[ 4]=box[t];
58 static inline int mul(int a, int b, uint8_t alog8[256]){
60 else return alog8[a+b];
63 #define ROT(x,s) ((x>>s)|(x<<(32-s))
65 static inline void mix(uint8_t state[4][4], uint32_t multbl[4][256]){
69 ((uint32_t *)(state))[i] = multbl[0][state[i][0]] ^ ROT(multbl[0][state[i][1]], 8)
70 ^ROT(multbl[0][state[i][2]],16) ^ ROT(multbl[0][state[i][3]],24);
73 ((uint32_t *)(state))[i] = multbl[0][state[i][0]] ^ multbl[1][state[i][1]]
74 ^multbl[2][state[i][2]] ^ multbl[3][state[i][3]];
79 void av_aes_decrypt(AVAES *a){
82 for(r=a->rounds-1; r>=0; r--){
84 addkey(a->state, a->round_key[r+1]);
86 mix(a->state, dec_multbl);
87 SUBSHIFT0((a->state[0]+0), inv_sbox)
88 SUBSHIFT3((a->state[0]+1), inv_sbox)
89 SUBSHIFT2((a->state[0]+2), inv_sbox)
90 SUBSHIFT1((a->state[0]+3), inv_sbox)
91 addkey(a->state, a->round_key[r]);
95 void av_aes_encrypt(AVAES *a){
98 for(r=0; r<a->rounds; r++){
99 addkey(a->state, a->round_key[r]);
100 SUBSHIFT0((a->state[0]+0), sbox)
101 SUBSHIFT1((a->state[0]+1), sbox)
102 SUBSHIFT2((a->state[0]+2), sbox)
103 SUBSHIFT3((a->state[0]+3), sbox)
105 addkey(a->state, a->round_key[r+1]);
107 mix(a->state, enc_multbl); //FIXME replace log8 by const / optimze mix as this can be simplified alot
111 // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
112 AVAES *av_aes_init(uint8_t *key, int key_bits) {
114 int i, j, t, rconpointer = 0;
123 for(i=0; i<255; i++){
131 for(i=0; i<256; i++){
132 j= i ? alog8[255-log8[i]] : 0;
133 j ^= (j<<1) ^ (j<<2) ^ (j<<3) ^ (j<<4);
134 j = (j ^ (j>>8) ^ 99) & 255;
137 // av_log(NULL, AV_LOG_ERROR, "%d, ", log8[i]);
142 if(key_bits!=128 && key_bits!=192 && key_bits!=256)
145 a= av_malloc(sizeof(AVAES));
148 memcpy(tk, key, KC*4);
150 for(t= 0; t < (rounds+1)*4; ) {
151 for(j = 0; (j < KC) && (t < (rounds+1)*4); j++, t++)
152 for(i = 0; i < 4; i++)
153 a->round_key[0][t][i] = tk[j][i];
155 for(i = 0; i < 4; i++)
156 tk[0][i] ^= sbox[tk[KC-1][(i+1)&3]];
157 tk[0][0] ^= rcon[rconpointer++];
159 for(j = 1; j < KC; j++){
160 if(KC != 8 || j != KC/2)
161 for(i = 0; i < 4; i++) tk[j][i] ^= tk[j-1][i];
163 for(i = 0; i < 4; i++)
164 tk[KC/2][i] ^= sbox[tk[KC/2 - 1][i]];
174 AVAES *a= av_aes_init("PI=3.141592654..", 128);
176 for(i=0; i<10000; i++){