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198 lines
6.2 KiB
198 lines
6.2 KiB
/* |
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* copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at> and Reimar Doeffinger |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "common.h" |
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#include "log.h" |
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#include "aes.h" |
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typedef struct AVAES{ |
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uint8_t round_key[15][4][4]; |
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uint8_t state[4][4]; |
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int rounds; |
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}AVAES; |
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static const uint8_t rcon[11] = { |
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0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c |
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}; |
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static uint8_t sbox[256]; |
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static uint8_t inv_sbox[256]; |
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#ifdef CONFIG_SMALL |
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static uint32_t enc_multbl[1][256]; |
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static uint32_t dec_multbl[1][256]; |
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#else |
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static uint32_t enc_multbl[4][256]; |
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static uint32_t dec_multbl[4][256]; |
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#endif |
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static inline void addkey(uint64_t state[2], uint64_t round_key[2]){ |
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state[0] ^= round_key[0]; |
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state[1] ^= round_key[1]; |
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} |
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#define SUBSHIFT0(s, box) s[0]=box[s[ 0]]; s[ 4]=box[s[ 4]]; s[ 8]=box[s[ 8]]; s[12]=box[s[12]]; |
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#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]; |
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#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]; |
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#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]; |
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#define ROT(x,s) ((x>>s)|(x<<(32-s)) |
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static inline void mix(uint8_t state[4][4], uint32_t multbl[4][256]){ |
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int i; |
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for(i=0; i<4; i++) |
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#ifdef CONFIG_SMALL |
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((uint32_t *)(state))[i] = multbl[0][state[i][0]] ^ ROT(multbl[0][state[i][1]], 8) |
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^ROT(multbl[0][state[i][2]],16) ^ ROT(multbl[0][state[i][3]],24); |
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#else |
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((uint32_t *)(state))[i] = multbl[0][state[i][0]] ^ multbl[1][state[i][1]] |
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^multbl[2][state[i][2]] ^ multbl[3][state[i][3]]; |
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#endif |
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} |
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void av_aes_decrypt(AVAES *a){ |
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int t, r; |
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addkey(a->state, a->round_key[a->rounds]); |
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for(r=a->rounds-1; r>=0; r--){ |
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if(r!=a->rounds-1) |
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mix(a->state, dec_multbl); |
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SUBSHIFT0((a->state[0]+0), inv_sbox) |
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SUBSHIFT3((a->state[0]+1), inv_sbox) |
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SUBSHIFT2((a->state[0]+2), inv_sbox) |
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SUBSHIFT1((a->state[0]+3), inv_sbox) |
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addkey(a->state, a->round_key[r]); |
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} |
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} |
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void av_aes_encrypt(AVAES *a){ |
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int r, t; |
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for(r=0; r<a->rounds; r++){ |
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addkey(a->state, a->round_key[r]); |
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SUBSHIFT0((a->state[0]+0), sbox) |
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SUBSHIFT1((a->state[0]+1), sbox) |
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SUBSHIFT2((a->state[0]+2), sbox) |
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SUBSHIFT3((a->state[0]+3), sbox) |
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if(r!=a->rounds-1) |
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mix(a->state, enc_multbl); //FIXME replace log8 by const / optimze mix as this can be simplified alot |
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} |
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addkey(a->state, a->round_key[r]); |
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} |
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static init_multbl(uint8_t tbl[256], int c[4], uint8_t *log8, uint8_t *alog8){ |
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int i; |
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for(i=4; i<1024; i++) |
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tbl[i]= alog8[ log8[i/4] + log8[c[i&3]] ]; |
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} |
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// this is based on the reference AES code by Paulo Barreto and Vincent Rijmen |
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AVAES *av_aes_init(uint8_t *key, int key_bits) { |
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AVAES *a; |
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int i, j, t, rconpointer = 0; |
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uint8_t tk[8][4]; |
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int KC= key_bits/32; |
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int rounds= KC + 6; |
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uint8_t log8[256]; |
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uint8_t alog8[512]; |
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if(!sbox[255]){ |
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j=1; |
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for(i=0; i<255; i++){ |
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alog8[i]= |
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alog8[i+255]= j; |
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log8[j]= i; |
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j^= j+j; |
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if(j>255) j^= 0x11B; |
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} |
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log8[0]= 255; |
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for(i=0; i<256; i++){ |
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j= i ? alog8[255-log8[i]] : 0; |
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j ^= (j<<1) ^ (j<<2) ^ (j<<3) ^ (j<<4); |
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j = (j ^ (j>>8) ^ 99) & 255; |
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inv_sbox[j]= i; |
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sbox [i]= j; |
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// av_log(NULL, AV_LOG_ERROR, "%d, ", log8[i]); |
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} |
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init_multbl(dec_multbl[0], (int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8); |
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init_multbl(dec_multbl[1], (int[4]){0xb, 0xe, 0x9, 0xd}, log8, alog8); |
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init_multbl(dec_multbl[2], (int[4]){0xd, 0xb, 0xe, 0x9}, log8, alog8); |
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init_multbl(dec_multbl[3], (int[4]){0x9, 0xd, 0xb, 0xe}, log8, alog8); |
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init_multbl(enc_multbl[0], (int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8); |
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init_multbl(enc_multbl[1], (int[4]){0x3, 0x2, 0x1, 0x1}, log8, alog8); |
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init_multbl(enc_multbl[2], (int[4]){0x1, 0x3, 0x2, 0x1}, log8, alog8); |
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init_multbl(enc_multbl[3], (int[4]){0x1, 0x1, 0x3, 0x2}, log8, alog8); |
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} |
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if(key_bits!=128 && key_bits!=192 && key_bits!=256) |
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return NULL; |
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a= av_malloc(sizeof(AVAES)); |
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a->rounds= rounds; |
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memcpy(tk, key, KC*4); |
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for(t= 0; t < (rounds+1)*4;) { |
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memcpy(a->round_key[0][t], tk, KC*4); |
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t+= KC; |
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for(i = 0; i < 4; i++) |
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tk[0][i] ^= sbox[tk[KC-1][(i+1)&3]]; |
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tk[0][0] ^= rcon[rconpointer++]; |
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for(j = 1; j < KC; j++){ |
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if(KC != 8 || j != KC/2) |
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for(i = 0; i < 4; i++) tk[j][i] ^= tk[j-1][i]; |
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else |
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for(i = 0; i < 4; i++) tk[j][i] ^= sbox[tk[j-1][i]]; |
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} |
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} |
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return a; |
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} |
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#ifdef TEST |
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int main(){ |
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int i,j,k; |
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AVAES *a= av_aes_init("PI=3.141592654..", 128); |
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uint8_t ct[16], pt[16], key[32]; |
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av_log_level= AV_LOG_DEBUG; |
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for(i=0; i<10000; i++){ |
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for(j=0; j<16; j++){ |
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pt[j]= random(); |
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} |
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memcpy(a->state, pt, 16); |
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{START_TIMER |
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av_aes_encrypt(a); |
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if(!(i&(i-1))) |
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av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", a->state[0][0], a->state[1][1], a->state[2][2], a->state[3][3]); |
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av_aes_decrypt(a); |
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STOP_TIMER("aes")} |
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for(j=0; j<16; j++){ |
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if(pt[j] != a->state[0][j]){ |
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av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], a->state[0][j]); |
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} |
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} |
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} |
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return 0; |
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} |
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#endif
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