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merge encrypt and decrypt so the source is simpler and the compiler can choose with inlining if it wants speed or small size

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Originally committed as revision 7494 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2007-01-14 19:39:38 +00:00
parent 28b5123546
commit 0c5d2819a5
1 changed files with 18 additions and 23 deletions
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41
libavutil/aes.c
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@ -71,40 +71,30 @@ static inline void mix(uint8_t state[4][4], uint32_t multbl[4][256]){
#endif
}
void av_aes_decrypt(AVAES *a){
static inline void crypt(AVAES *a, int s, uint8_t *sbox, uint32_t *multbl){
int t, r;
for(r=a->rounds; r>1; r--){
addkey(a->state, a->round_key[r]);
SUBSHIFT3x((a->state[0]+1))
SUBSHIFT3x((a->state[0]+1+s))
SUBSHIFT2x((a->state[0]+2))
SUBSHIFT1x((a->state[0]+3))
mix(a->state, dec_multbl);
SUBSHIFT1x((a->state[0]+3-s))
mix(a->state, multbl);
}
addkey(a->state, a->round_key[1]);
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)
SUBSHIFT0((a->state[0]+0 ), sbox)
SUBSHIFT3((a->state[0]+1+s), sbox)
SUBSHIFT2((a->state[0]+2 ), sbox)
SUBSHIFT1((a->state[0]+3-s), sbox)
addkey(a->state, a->round_key[0]);
}
void av_aes_encrypt(AVAES *a){
int r, t;
void av_aes_decrypt(AVAES *a){
crypt(a, 0, inv_sbox, dec_multbl);
}
for(r=0; r<a->rounds-1; r++){
addkey(a->state, a->round_key[r]);
SUBSHIFT1x((a->state[0]+1))
SUBSHIFT2x((a->state[0]+2))
SUBSHIFT3x((a->state[0]+3))
mix(a->state, enc_multbl);
}
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]);
void av_aes_encrypt(AVAES *a){
crypt(a, 2, sbox, enc_multbl);
}
static init_multbl2(uint8_t tbl[1024], int c[4], uint8_t *log8, uint8_t *alog8, uint8_t *sbox){
@ -188,6 +178,11 @@ AVAES *av_aes_init(uint8_t *key, int key_bits, int decrypt) {
a->round_key[i][0][j]= sbox[a->round_key[i][0][j]];
mix(a->round_key[i], dec_multbl);
}
}else{
for(i=0; i<(rounds+1)/2; i++){
for(j=0; j<16; j++)
FFSWAP(int, a->round_key[i][0][j], a->round_key[rounds-i][0][j]);
}
}
return a;