AES: masked config: increase total transfer speed by 5% by removing zeroing
On MBEDTLS_AES_128_BIT_MASKED config the overall DTLS transfer speed can be
increased by 3..5% or so on a Cortex-M4 by removing 472 bytes worth of
buffer zeroing done on each block {en|de}cryption. The buffer zeroings
were done before overwriting them on in masking code.
Signed-off-by: Tero Jääskö <tero.jaasko@arm.com>
diff --git a/library/aes.c b/library/aes.c
index 50f9702..061b6fd 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -1421,9 +1421,9 @@
uint8_t round_ctrl_table[( 14 + AES_SCA_CM_ROUNDS + 2 )];
#if defined MBEDTLS_AES_128_BIT_MASKED
- uint32_t rk_masked[MBEDTLS_AES_128_EXPANDED_KEY_SIZE_IN_WORDS] = {0};
- uint8_t sbox_masked[256] = {0};
- uint32_t mask[10] = {0};
+ uint32_t rk_masked[MBEDTLS_AES_128_EXPANDED_KEY_SIZE_IN_WORDS];
+ uint8_t sbox_masked[256];
+ uint32_t mask[10];
#endif
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY)