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ffmpeg/libavutil/aes.c

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/*
* copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at> and 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 "log.h"
#include "aes.h"
typedef struct AVAES{
uint8_t round_key[15][4][4];
uint8_t state[4][4];
int rounds;
}AVAES;
static const uint8_t rcon[11] = {
0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c
};
static uint8_t sbox[256];
static uint8_t inv_sbox[256];
#ifdef 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
static inline void addkey(uint64_t state[2], uint64_t round_key[2]){
state[0] ^= round_key[0];
state[1] ^= round_key[1];
}
#define SUBSHIFT0(s, box) s[0]=box[s[ 0]]; s[ 4]=box[s[ 4]]; s[ 8]=box[s[ 8]]; s[12]=box[s[12]];
#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];
#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];
#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];
#define SUBSHIFT1x(s, box) t=s[0]; s[0]=s[ 4]; s[ 4]=s[ 8]; s[ 8]=s[12]; s[12]=t;
#define SUBSHIFT2x(s, box) t=s[0]; s[0]=s[ 8]; s[ 8]= t; t=s[ 4]; s[ 4]=s[12]; s[12]=t;
#define SUBSHIFT3x(s, box) t=s[0]; s[0]=s[12]; s[12]=s[ 8]; s[ 8]=s[ 4]; s[ 4]=t;
#define ROT(x,s) ((x<<s)|(x>>(32-s)))
static inline void mix(uint8_t state[4][4], uint32_t multbl[4][256]){
int i;
for(i=0; i<4; i++)
#ifdef CONFIG_SMALL
((uint32_t *)(state))[i] = multbl[0][state[i][0]] ^ ROT(multbl[0][state[i][1]], 8)
^ROT(multbl[0][state[i][2]],16) ^ ROT(multbl[0][state[i][3]],24);
#else
((uint32_t *)(state))[i] = multbl[0][state[i][0]] ^ multbl[1][state[i][1]]
^multbl[2][state[i][2]] ^ multbl[3][state[i][3]];
#endif
}
void av_aes_decrypt(AVAES *a){
int t, r;
addkey(a->state, a->round_key[a->rounds]);
for(r=a->rounds-1; r>=0; r--){
if(r!=a->rounds-1)
mix(a->state, dec_multbl);
SUBSHIFT0((a->state[0]+0), inv_sbox)
SUBSHIFT3((a->state[0]+1), inv_sbox)
SUBSHIFT2((a->state[0]+2), inv_sbox)
SUBSHIFT1((a->state[0]+3), inv_sbox)
addkey(a->state, a->round_key[r]);
}
}
void av_aes_encrypt(AVAES *a){
int r, t;
for(r=0; r<a->rounds-1; r++){
addkey(a->state, a->round_key[r]);
SUBSHIFT1x((a->state[0]+1), sbox)
SUBSHIFT2x((a->state[0]+2), sbox)
SUBSHIFT3x((a->state[0]+3), sbox)
mix(a->state, enc_multbl); //FIXME replace log8 by const / optimze mix as this can be simplified alot
}
addkey(a->state, a->round_key[r]);
SUBSHIFT0((a->state[0]+0), sbox)
SUBSHIFT1((a->state[0]+1), sbox)
SUBSHIFT2((a->state[0]+2), sbox)
SUBSHIFT3((a->state[0]+3), sbox)
addkey(a->state, a->round_key[r+1]);
}
static init_multbl(uint8_t tbl[1024], int c[4], uint8_t *log8, uint8_t *alog8){
int i;
for(i=4; i<1024; i++)
tbl[i]= alog8[ log8[i/4] + log8[c[i&3]] ];
}
static init_multbl2(uint8_t tbl[1024], int c[4], uint8_t *log8, uint8_t *alog8, uint8_t *sbox){
int i;
for(i=0; i<1024; i++){
int x= sbox[i/4];
if(x) tbl[i]= alog8[ log8[x] + log8[c[i&3]] ];
}
}
// this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
AVAES *av_aes_init(uint8_t *key, int key_bits) {
AVAES *a;
int i, j, t, rconpointer = 0;
uint8_t tk[8][4];
int KC= key_bits/32;
int rounds= KC + 6;
uint8_t log8[256];
uint8_t alog8[512];
if(!sbox[255]){
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;
}
log8[0]= 255;
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;
// av_log(NULL, AV_LOG_ERROR, "%d, ", log8[i]);
}
init_multbl(dec_multbl[0], (int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8);
#ifndef CONFIG_SMALL
init_multbl(dec_multbl[1], (int[4]){0xb, 0xe, 0x9, 0xd}, log8, alog8);
init_multbl(dec_multbl[2], (int[4]){0xd, 0xb, 0xe, 0x9}, log8, alog8);
init_multbl(dec_multbl[3], (int[4]){0x9, 0xd, 0xb, 0xe}, log8, alog8);
#endif
init_multbl2(enc_multbl[0], (int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
#ifndef CONFIG_SMALL
init_multbl2(enc_multbl[1], (int[4]){0x3, 0x2, 0x1, 0x1}, log8, alog8, sbox);
init_multbl2(enc_multbl[2], (int[4]){0x1, 0x3, 0x2, 0x1}, log8, alog8, sbox);
init_multbl2(enc_multbl[3], (int[4]){0x1, 0x1, 0x3, 0x2}, log8, alog8, sbox);
#endif
}
if(key_bits!=128 && key_bits!=192 && key_bits!=256)
return NULL;
a= av_malloc(sizeof(AVAES));
a->rounds= rounds;
memcpy(tk, key, KC*4);
for(t= 0; t < (rounds+1)*4;) {
memcpy(a->round_key[0][t], tk, KC*4);
t+= KC;
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/2)
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]];
}
}
return a;
}
#ifdef TEST
int main(){
int i,j,k;
AVAES *a= av_aes_init("PI=3.141592654..", 128);
uint8_t zero[16]= {0};
uint8_t pt[16]= {0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3};
uint8_t ct[16]= {0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf};
AVAES *b= av_aes_init(zero, 128);
/* uint8_t key[16]= {0x42, 0x78, 0xb8, 0x40, 0xfb, 0x44, 0xaa, 0xa7, 0x57, 0xc1, 0xbf, 0x04, 0xac, 0xbe, 0x1a, 0x3e};
uint8_t IV[16] = {0x57, 0xf0, 0x2a, 0x5c, 0x53, 0x39, 0xda, 0xeb, 0x0a, 0x29, 0x08, 0xa0, 0x6a, 0xc6, 0x39, 0x3f};
uint8_t pt[16] = {0x3c, 0x88, 0x8b, 0xbb, 0xb1, 0xa8, 0xeb, 0x9f, 0x3e, 0x9b, 0x87, 0xac, 0xaa, 0xd9, 0x86, 0xc4};
// 66e2f7071c83083b8a557971918850e5
uint8_t ct[16] = {0x47, 0x9c, 0x89, 0xec, 0x14, 0xbc, 0x98, 0x99, 0x4e, 0x62, 0xb2, 0xc7, 0x05, 0xb5, 0x0, 0x14e};
// 175bd7832e7e60a1e92aac568a861eb7*/
uint8_t ckey[16]= {0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59};
uint8_t cct[16] = {0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65};
AVAES *c= av_aes_init(ckey, 128);
av_log_level= AV_LOG_DEBUG;
memcpy(b->state, ct, 16);
av_aes_decrypt(b);
for(j=0; j<16; j++)
if(pt[j] != b->state[0][j]){
av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, pt[j], b->state[0][j]);
}
memcpy(c->state, cct, 16);
av_aes_decrypt(c);
for(j=0; j<16; j++)
if(zero[j] != c->state[0][j]){
av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, zero[j], c->state[0][j]);
}
for(i=0; i<10000; i++){
for(j=0; j<16; j++){
pt[j]= random();
}
memcpy(a->state, pt, 16);
{START_TIMER
av_aes_encrypt(a);
if(!(i&(i-1)))
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]);
av_aes_decrypt(a);
STOP_TIMER("aes")}
for(j=0; j<16; j++){
if(pt[j] != a->state[0][j]){
av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], a->state[0][j]);
}
}
}
return 0;
}
#endif
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