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cmac.c: optimize make_kn and move zero_iv to const segment.

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This commit is contained in:
Andy Polyakov 2012-01-06 13:19:16 +00:00
parent ce0727f9bd
commit 03cf7e784c
1 changed files with 9 additions and 10 deletions
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19
crypto/cmac/cmac.c
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@ -77,19 +77,17 @@ struct CMAC_CTX_st
/* Make temporary keys K1 and K2 */ /* Make temporary keys K1 and K2 */
static void make_kn(unsigned char *k1, unsigned char *l, int bl) static void make_kn(unsigned char *k1, const unsigned char *l, int bl)
{ {
int i; int i;
unsigned char c = l[0], carry = c>>7, cnext;
/* Shift block to left, including carry */ /* Shift block to left, including carry */
for (i = 0; i < bl; i++) for (i = 0; i < bl-1; i++, c = cnext)
{ k1[i] = (c << 1) | ((cnext=l[i+1]) >> 7);
k1[i] = l[i] << 1;
if (i < bl - 1 && l[i + 1] & 0x80)
k1[i] |= 1;
}
/* If MSB set fixup with R */ /* If MSB set fixup with R */
if (l[0] & 0x80) k1[i] = (c << 1) ^ ((0-carry)&(bl==16?0x87:0x1b));
k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
} }
CMAC_CTX *CMAC_CTX_new(void) CMAC_CTX *CMAC_CTX_new(void)
@ -143,7 +141,8 @@ int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen, int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
const EVP_CIPHER *cipher, ENGINE *impl) const EVP_CIPHER *cipher, ENGINE *impl)
{ {
static unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH]; __fips_constseg
static const unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH] = {0};
/* All zeros means restart */ /* All zeros means restart */
if (!key && !cipher && !impl && keylen == 0) if (!key && !cipher && !impl && keylen == 0)
{ {