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Tune up AES CFB. Performance improvement varies from 10% to 50% from

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platform to platform. Its absolute value is within few percents
marginal from that of ECB.
This commit is contained in:
Andy Polyakov 2006-05-30 07:20:13 +00:00
parent 4d4e08ec1c
commit 21f0db692d
2 changed files with 96 additions and 13 deletions
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2
crypto/aes/aes.h
View File

@ -99,7 +99,7 @@ void AES_cbc_encrypt(const unsigned char *in, unsigned char *out,
const unsigned long length, const AES_KEY *key,
unsigned char *ivec, const int enc);
void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,
const unsigned long length, const AES_KEY *key,
unsigned long length, const AES_KEY *key,
unsigned char *ivec, int *num, const int enc);
void AES_cfb1_encrypt(const unsigned char *in, unsigned char *out,
const unsigned long length, const AES_KEY *key,

107
crypto/aes/aes_cfb.c
View File

@ -116,39 +116,122 @@
#include "aes_locl.h"
#include "e_os.h"
#define STRICT_ALIGNMENT
#if defined(__i386) || defined(__i386__) || \
defined(__x86_64) || defined(__x86_64__) || \
defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64)
# undef STRICT_ALIGNMENT
#endif
/* The input and output encrypted as though 128bit cfb mode is being
* used. The extra state information to record how much of the
* 128bit block we have used is contained in *num;
*/
void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,
const unsigned long length, const AES_KEY *key,
unsigned long length, const AES_KEY *key,
unsigned char *ivec, int *num, const int enc) {
unsigned int n;
unsigned long l = length;
unsigned char c;
unsigned int n;
unsigned long l = 0;
assert(in && out && key && ivec && num);
assert(in && out && key && ivec && num);
n = *num;
n = *num;
#if !defined(OPENSSL_SMALL_FOOTPRINT)
if (AES_BLOCK_SIZE%sizeof(size_t) == 0) { /* always true actually */
if (enc) {
while (l--) {
if (n) {
while (length) {
*(out++) = ivec[n] ^= *(in++);
length--;
if(!(n = (n + 1) % AES_BLOCK_SIZE))
break;
}
}
#if defined(STRICT_ALIGNMENT)
if (((size_t)in|(size_t)out)%sizeof(size_t) != 0)
goto enc_unaligned;
#endif
while ((l + AES_BLOCK_SIZE) <= length) {
unsigned int i;
AES_encrypt(ivec, ivec, key);
for (i=0;i<AES_BLOCK_SIZE;i+=sizeof(size_t)) {
*(size_t*)(out+l+i) =
*(size_t*)(ivec+i) ^= *(size_t*)(in+l+i);
}
l += AES_BLOCK_SIZE;
}
if (l < length) {
AES_encrypt(ivec, ivec, key);
do { out[l] = ivec[n] ^= in[l];
l++; n++;
} while (l < length);
}
} else {
if (n) {
while (length) {
unsigned char c;
*(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c;
length--;
if(!(n = (n + 1) % AES_BLOCK_SIZE))
break;
}
}
#if defined(STRICT_ALIGNMENT)
if (((size_t)in|(size_t)out)%sizeof(size_t) != 0)
goto dec_unaligned;
#endif
while (l + AES_BLOCK_SIZE <= length) {
unsigned int i;
AES_encrypt(ivec, ivec, key);
for (i=0;i<AES_BLOCK_SIZE;i+=sizeof(size_t)) {
size_t t = *(size_t*)(in+l+i);
*(size_t*)(out+l+i) = *(size_t*)(ivec+i) ^ t;
*(size_t*)(ivec+i) = t;
}
l += AES_BLOCK_SIZE;
}
if (l < length) {
AES_encrypt(ivec, ivec, key);
do { unsigned char c;
out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c;
l++; n++;
} while (l < length);
}
}
*num = n;
return;
}
#endif
/* this code would be commonly eliminated by x86* compiler */
if (enc) {
#if defined(STRICT_ALIGNMENT) && !defined(OPENSSL_SMALL_FOOTPRINT)
enc_unaligned:
#endif
while (l<length) {
if (n == 0) {
AES_encrypt(ivec, ivec, key);
}
ivec[n] = *(out++) = *(in++) ^ ivec[n];
out[l] = ivec[n] ^= in[l];
l++;
n = (n+1) % AES_BLOCK_SIZE;
}
} else {
while (l--) {
#if defined(STRICT_ALIGNMENT) && !defined(OPENSSL_SMALL_FOOTPRINT)
dec_unaligned:
#endif
while (l<length) {
unsigned char c;
if (n == 0) {
AES_encrypt(ivec, ivec, key);
}
c = *(in);
*(out++) = *(in++) ^ ivec[n];
ivec[n] = c;
out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c;
l++;
n = (n+1) % AES_BLOCK_SIZE;
}
}