lib/mbedtls
1
0
Fork 0
mirror of https://github.com/Mbed-TLS/mbedtls.git synced 2025-08-01 10:06:53 +03:00
Code Activity

Merge pull request #8908 from daverodgman/cmac-perf

Browse Source 
CMAC size and perf
This commit is contained in:
Dave Rodgman
2024-03-12 13:17:00 +00:00
committed by GitHub
parent a7f3c4e1d0 5ba2b2b8cc
commit e0ffb1d2e9
1 changed files with 14 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
library/cmac.c
View File

@ -56,22 +56,29 @@ static int cmac_multiply_by_u(unsigned char *output,
size_t blocksize) size_t blocksize)
{ {
const unsigned char R_128 = 0x87; const unsigned char R_128 = 0x87;
const unsigned char R_64 = 0x1B;
unsigned char R_n, mask; unsigned char R_n, mask;
unsigned char overflow = 0x00; uint32_t overflow = 0x00;
int i; int i;
if (blocksize == MBEDTLS_AES_BLOCK_SIZE) { if (blocksize == MBEDTLS_AES_BLOCK_SIZE) {
R_n = R_128; R_n = R_128;
} else if (blocksize == MBEDTLS_DES3_BLOCK_SIZE) { }
#if defined(MBEDTLS_DES_C)
else if (blocksize == MBEDTLS_DES3_BLOCK_SIZE) {
const unsigned char R_64 = 0x1B;
R_n = R_64; R_n = R_64;
} else { }
#endif
else {
return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA; return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA;
} }
for (i = (int) blocksize - 1; i >= 0; i--) { for (i = (int) blocksize - 4; i >= 0; i -= 4) {
output[i] = input[i] << 1 | overflow; uint32_t i32 = MBEDTLS_GET_UINT32_BE(&input[i], 0);
overflow = input[i] >> 7; uint32_t new_overflow = i32 >> 31;
i32 = (i32 << 1) | overflow;
MBEDTLS_PUT_UINT32_BE(i32, &output[i], 0);
overflow = new_overflow;
} }
/* mask = ( input[0] >> 7 ) ? 0xff : 0x00 /* mask = ( input[0] >> 7 ) ? 0xff : 0x00