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lavu/aes: add runtime dispatch for crypt function

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This commit is contained in:
Rodger Combs 2015-10-11 22:14:20 -05:00
parent ec588db56f
commit 15ff5c7215
2 changed files with 34 additions and 18 deletions
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51
libavutil/aes.c
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@ -126,31 +126,44 @@ static inline void aes_crypt(AVAES *a, int s, const uint8_t *sbox,
subshift(&a->state[0], s, sbox);
}
void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int decrypt)
static void aes_encrypt(AVAES *a, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int rounds)
{
while (count--) {
addkey_s(&a->state[1], src, &a->round_key[a->rounds]);
if (decrypt) {
aes_crypt(a, 0, inv_sbox, dec_multbl);
if (iv) {
addkey_s(&a->state[0], iv, &a->state[0]);
memcpy(iv, src, 16);
}
addkey_d(dst, &a->state[0], &a->round_key[0]);
} else {
if (iv)
addkey_s(&a->state[1], iv, &a->state[1]);
aes_crypt(a, 2, sbox, enc_multbl);
addkey_d(dst, &a->state[0], &a->round_key[0]);
if (iv)
memcpy(iv, dst, 16);
}
addkey_s(&a->state[1], src, &a->round_key[rounds]);
if (iv)
addkey_s(&a->state[1], iv, &a->state[1]);
aes_crypt(a, 2, sbox, enc_multbl);
addkey_d(dst, &a->state[0], &a->round_key[0]);
if (iv)
memcpy(iv, dst, 16);
src += 16;
dst += 16;
}
}
static void aes_decrypt(AVAES *a, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int rounds)
{
while (count--) {
addkey_s(&a->state[1], src, &a->round_key[rounds]);
aes_crypt(a, 0, inv_sbox, dec_multbl);
if (iv) {
addkey_s(&a->state[0], iv, &a->state[0]);
memcpy(iv, src, 16);
}
addkey_d(dst, &a->state[0], &a->round_key[0]);
src += 16;
dst += 16;
}
}
void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int decrypt)
{
a->crypt(a, dst, src, count, iv, a->rounds);
}
static void init_multbl2(uint32_t tbl[][256], const int c[4],
const uint8_t *log8, const uint8_t *alog8,
const uint8_t *sbox)
@ -186,6 +199,8 @@ int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
uint8_t log8[256];
uint8_t alog8[512];
a->crypt = decrypt ? aes_decrypt : aes_encrypt;
if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]) {
j = 1;
for (i = 0; i < 255; i++) {

1
libavutil/aes_internal.h
View File

@ -36,6 +36,7 @@ typedef struct AVAES {
av_aes_block round_key[15];
av_aes_block state[2];
int rounds;
void (*crypt)(struct AVAES *a, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int rounds);
} AVAES;
#endif /* AVUTIL_AES_INTERNAL_H */