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crypto: Make aes_unwrap look similar to aes_wrap 

Running basic performance testing on x86 shows new and old code within a
few percent of each other.  The main penalty is the AES AF_ALG
invocation.
This commit is contained in:
Denis Kenzior 2017-08-31 12:18:07 -05:00
parent 4f865ba9f8
commit 6d6fa57550
1 changed files with 11 additions and 11 deletions
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22
src/crypto.c
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@ -125,11 +125,12 @@ bool cmac_aes(const void *key, size_t key_len,
bool aes_unwrap(const uint8_t *kek, const uint8_t *in, size_t len,
uint8_t *out)
{
uint8_t b[16];
uint8_t *r;
uint64_t b[2];
uint64_t *r;
size_t n = (len - 8) >> 3;
int i, j;
struct l_cipher *cipher;
uint64_t t = n * 6;
cipher = l_cipher_new(L_CIPHER_AES, kek, 16);
if (!cipher)
@ -141,23 +142,22 @@ bool aes_unwrap(const uint8_t *kek, const uint8_t *in, size_t len,
/* Unwrap */
for (j = 5; j >= 0; j--) {
r = out + (n - 1) * 8;
r = (uint64_t *) out + n - 1;
for (i = n; i >= 1; i--) {
memcpy(b + 8, r, 8);
b[7] ^= n * j + i;
for (i = n; i >= 1; i--, t--) {
b[0] ^= L_CPU_TO_BE64(t);
b[1] = L_GET_UNALIGNED(r);
l_cipher_decrypt(cipher, b, b, 16);
memcpy(r, b + 8, 8);
r -= 8;
L_PUT_UNALIGNED(b[1], r);
r -= 1;
}
}
l_cipher_free(cipher);
/* Check IV */
for (i = 0; i < 8; i++)
if (b[i] != 0xA6)
return false;
if (b[0] != 0xa6a6a6a6a6a6a6a6)
return false;
return true;
}