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aes: allow unaligned input and output buffers

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Signed-off-by: Mans Rullgard <mans@mansr.com>
This commit is contained in:
Mans Rullgard 2011-07-03 19:13:20 +01:00
parent 6c374bc0b4
commit d04d9f24a0
1 changed files with 26 additions and 15 deletions
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41
libavutil/aes.c
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@ -22,6 +22,7 @@
#include "common.h"
#include "aes.h"
#include "intreadwrite.h"
typedef union {
uint64_t u64[2];
@ -67,6 +68,20 @@ static inline void addkey(av_aes_block *dst, const av_aes_block *src,
dst->u64[1] = src->u64[1] ^ round_key->u64[1];
}
static inline void addkey_s(av_aes_block *dst, const uint8_t *src,
const av_aes_block *round_key)
{
dst->u64[0] = AV_RN64(src) ^ round_key->u64[0];
dst->u64[1] = AV_RN64(src + 8) ^ round_key->u64[1];
}
static inline void addkey_d(uint8_t *dst, const av_aes_block *src,
const av_aes_block *round_key)
{
AV_WN64(dst, src->u64[0] ^ round_key->u64[0]);
AV_WN64(dst + 8, src->u64[1] ^ round_key->u64[1]);
}
static void subshift(av_aes_block s0[2], int s, const uint8_t *box)
{
av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s);
@ -119,32 +134,28 @@ static inline void 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)
void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int decrypt)
{
av_aes_block *dst = (av_aes_block *) dst_;
const av_aes_block *src = (const av_aes_block *) src_;
av_aes_block *iv = (av_aes_block *) iv_;
while (count--) {
addkey(&a->state[1], src, &a->round_key[a->rounds]);
addkey_s(&a->state[1], src, &a->round_key[a->rounds]);
if (decrypt) {
crypt(a, 0, inv_sbox, dec_multbl);
if (iv) {
addkey(&a->state[0], &a->state[0], iv);
*iv = *src;
addkey_s(&a->state[0], iv, &a->state[0]);
memcpy(iv, src, 16);
}
addkey(dst, &a->state[0], &a->round_key[0]);
addkey_d(dst, &a->state[0], &a->round_key[0]);
} else {
if (iv)
addkey(&a->state[1], &a->state[1], iv);
addkey_s(&a->state[1], iv, &a->state[1]);
crypt(a, 2, sbox, enc_multbl);
addkey(dst, &a->state[0], &a->round_key[0]);
addkey_d(dst, &a->state[0], &a->round_key[0]);
if (iv)
*iv = *dst;
memcpy(iv, dst, 16);
}
src++;
dst++;
src += 16;
dst += 16;
}
}