232 lines
7.3 KiB
C
232 lines
7.3 KiB
C
/*
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* copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
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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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* some optimization ideas from aes128.c by Reimar Doeffinger
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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[10] = {
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0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
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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 SUBSHIFT1x(s) t=s[0]; s[0]=s[ 4]; s[ 4]=s[ 8]; s[ 8]=s[12]; s[12]=t;
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#define SUBSHIFT2x(s) t=s[0]; s[0]=s[ 8]; s[ 8]= t; t=s[ 4]; s[ 4]=s[12]; s[12]=t;
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#define SUBSHIFT3x(s) t=s[0]; s[0]=s[12]; s[12]=s[ 8]; s[ 8]=s[ 4]; s[ 4]=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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static inline void crypt(AVAES *a, int s, uint8_t *sbox, uint32_t *multbl){
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int t, r;
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for(r=a->rounds; r>1; r--){
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addkey(a->state, a->round_key[r]);
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SUBSHIFT3x((a->state[0]+1+s))
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SUBSHIFT2x((a->state[0]+2))
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SUBSHIFT1x((a->state[0]+3-s))
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mix(a->state, multbl);
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}
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addkey(a->state, a->round_key[1]);
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SUBSHIFT0((a->state[0]+0 ), sbox)
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SUBSHIFT3((a->state[0]+1+s), sbox)
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SUBSHIFT2((a->state[0]+2 ), sbox)
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SUBSHIFT1((a->state[0]+3-s), sbox)
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addkey(a->state, a->round_key[0]);
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}
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void av_aes_decrypt(AVAES *a){
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crypt(a, 0, inv_sbox, dec_multbl);
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}
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void av_aes_encrypt(AVAES *a){
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crypt(a, 2, sbox, enc_multbl);
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}
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static void init_multbl2(uint8_t tbl[1024], int c[4], uint8_t *log8, uint8_t *alog8, uint8_t *sbox){
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int i, j;
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for(i=0; i<1024; i++){
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int x= sbox[i/4];
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if(x) tbl[i]= alog8[ log8[x] + log8[c[i&3]] ];
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}
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#ifndef CONFIG_SMALL
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for(j=256; j<1024; j++)
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for(i=0; i<4; i++)
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tbl[4*j+i]= tbl[4*j + ((i-1)&3) - 1024];
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#endif
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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, int decrypt) {
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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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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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}
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init_multbl2(dec_multbl[0], (int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8, inv_sbox);
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init_multbl2(enc_multbl[0], (int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
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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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if(decrypt){
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for(i=1; i<rounds; i++){
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for(j=0; j<16; j++)
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a->round_key[i][0][j]= sbox[a->round_key[i][0][j]];
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mix(a->round_key[i], dec_multbl);
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}
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}else{
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for(i=0; i<(rounds+1)/2; i++){
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for(j=0; j<16; j++)
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FFSWAP(int, a->round_key[i][0][j], a->round_key[rounds-i][0][j]);
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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;
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AVAES *ae= av_aes_init("PI=3.141592654..", 128, 0);
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AVAES *ad= av_aes_init("PI=3.141592654..", 128, 1);
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uint8_t rkey[2][16]= {
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{0},
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{0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59}};
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uint8_t pt[16], rpt[2][16]= {
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{0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3},
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{0}};
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uint8_t rct[2][16]= {
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{0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf},
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{0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65}};
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av_log_level= AV_LOG_DEBUG;
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for(i=0; i<2; i++){
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AVAES *b= av_aes_init(rkey[i], 128, 1);
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memcpy(b->state, rct[i], 16);
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av_aes_decrypt(b);
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for(j=0; j<16; j++)
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if(rpt[i][j] != b->state[0][j])
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av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], b->state[0][j]);
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}
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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(ae->state, pt, 16);
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{START_TIMER
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av_aes_encrypt(ae);
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if(!(i&(i-1)))
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av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", ae->state[0][0], ae->state[1][1], ae->state[2][2], ae->state[3][3]);
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memcpy(ad->state, ae->state, 16);
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av_aes_decrypt(ad);
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STOP_TIMER("aes")}
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for(j=0; j<16; j++){
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if(pt[j] != ad->state[0][j]){
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av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], ad->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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