Using 64-bit arithmetic increases the performance for xts-aes-128
when built with gcrypt:
Encrypt: 235 MB/s -> 320 MB/s
Decrypt: 245 MB/s -> 325 MB/s
Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
---
crypto/xts.c | 52 +++++++++++++++++++++++++++++++++-------------------
1 file changed, 33 insertions(+), 19 deletions(-)
diff --git a/crypto/xts.c b/crypto/xts.c
index ded4365191..f109c8a3ee 100644
--- a/crypto/xts.c
+++ b/crypto/xts.c
@@ -31,6 +31,12 @@ typedef struct {
uint64_t b;
} xts_uint128;
+#define xts_uint128_xor(D, S1, S2) \
+ do { \
+ (D)->a = (S1)->a ^ (S2)->a; \
+ (D)->b = (S1)->b ^ (S2)->b; \
+ } while (0)
+
static void xts_mult_x(uint8_t *I)
{
int x;
@@ -59,25 +65,19 @@ static void xts_mult_x(uint8_t *I)
*/
static void xts_tweak_encdec(const void *ctx,
xts_cipher_func *func,
- const uint8_t *src,
- uint8_t *dst,
- uint8_t *iv)
+ const xts_uint128 *src,
+ xts_uint128 *dst,
+ xts_uint128 *iv)
{
- unsigned long x;
-
/* tweak encrypt block i */
- for (x = 0; x < XTS_BLOCK_SIZE; x++) {
- dst[x] = src[x] ^ iv[x];
- }
+ xts_uint128_xor(dst, src, iv);
- func(ctx, XTS_BLOCK_SIZE, dst, dst);
+ func(ctx, XTS_BLOCK_SIZE, (uint8_t *)dst, (uint8_t *)dst);
- for (x = 0; x < XTS_BLOCK_SIZE; x++) {
- dst[x] = dst[x] ^ iv[x];
- }
+ xts_uint128_xor(dst, dst, iv);
/* LFSR the tweak */
- xts_mult_x(iv);
+ xts_mult_x((uint8_t *)iv);
}
@@ -110,7 +110,11 @@ void xts_decrypt(const void *datactx,
encfunc(tweakctx, XTS_BLOCK_SIZE, (uint8_t *)&T, iv);
for (i = 0; i < lim; i++) {
- xts_tweak_encdec(datactx, decfunc, src, dst, (uint8_t *)&T);
+ xts_uint128 S, D;
+
+ memcpy(&S, src, XTS_BLOCK_SIZE);
+ xts_tweak_encdec(datactx, decfunc, &S, &D, &T);
+ memcpy(dst, &D, XTS_BLOCK_SIZE);
src += XTS_BLOCK_SIZE;
dst += XTS_BLOCK_SIZE;
@@ -118,11 +122,13 @@ void xts_decrypt(const void *datactx,
/* if length is not a multiple of XTS_BLOCK_SIZE then */
if (mo > 0) {
+ xts_uint128 S, D;
memcpy(&CC, &T, XTS_BLOCK_SIZE);
xts_mult_x((uint8_t *)&CC);
/* PP = tweak decrypt block m-1 */
- xts_tweak_encdec(datactx, decfunc, src, (uint8_t *)&PP, (uint8_t
*)&CC);
+ memcpy(&S, src, XTS_BLOCK_SIZE);
+ xts_tweak_encdec(datactx, decfunc, &S, &PP, &CC);
/* Pm = first length % XTS_BLOCK_SIZE bytes of PP */
for (i = 0; i < mo; i++) {
@@ -134,7 +140,8 @@ void xts_decrypt(const void *datactx,
}
/* Pm-1 = Tweak uncrypt CC */
- xts_tweak_encdec(datactx, decfunc, (uint8_t *)&CC, dst, (uint8_t *)&T);
+ xts_tweak_encdec(datactx, decfunc, &CC, &D, &T);
+ memcpy(dst, &D, XTS_BLOCK_SIZE);
}
/* Decrypt the iv back */
@@ -171,7 +178,11 @@ void xts_encrypt(const void *datactx,
encfunc(tweakctx, XTS_BLOCK_SIZE, (uint8_t *)&T, iv);
for (i = 0; i < lim; i++) {
- xts_tweak_encdec(datactx, encfunc, src, dst, (uint8_t *)&T);
+ xts_uint128 S, D;
+
+ memcpy(&S, src, XTS_BLOCK_SIZE);
+ xts_tweak_encdec(datactx, encfunc, &S, &D, &T);
+ memcpy(dst, &D, XTS_BLOCK_SIZE);
dst += XTS_BLOCK_SIZE;
src += XTS_BLOCK_SIZE;
@@ -179,8 +190,10 @@ void xts_encrypt(const void *datactx,
/* if length is not a multiple of XTS_BLOCK_SIZE then */
if (mo > 0) {
+ xts_uint128 S, D;
/* CC = tweak encrypt block m-1 */
- xts_tweak_encdec(datactx, encfunc, src, (uint8_t *)&CC, (uint8_t *)&T);
+ memcpy(&S, src, XTS_BLOCK_SIZE);
+ xts_tweak_encdec(datactx, encfunc, &S, &CC, &T);
/* Cm = first length % XTS_BLOCK_SIZE bytes of CC */
for (i = 0; i < mo; i++) {
@@ -193,7 +206,8 @@ void xts_encrypt(const void *datactx,
}
/* Cm-1 = Tweak encrypt PP */
- xts_tweak_encdec(datactx, encfunc, (uint8_t *)&PP, dst, (uint8_t *)&T);
+ xts_tweak_encdec(datactx, encfunc, &PP, &D, &T);
+ memcpy(dst, &D, XTS_BLOCK_SIZE);
}
/* Decrypt the iv back */
--
2.17.1
