74 lines
2.3 KiB
C
74 lines
2.3 KiB
C
#include "verify.h"
|
|
#include <immintrin.h>
|
|
#include <stdint.h>
|
|
#include <stdlib.h>
|
|
|
|
/*************************************************
|
|
* Name: PQCLEAN_KYBER512_AVX2_verify
|
|
*
|
|
* Description: Compare two arrays for equality in constant time.
|
|
*
|
|
* Arguments: const uint8_t *a: pointer to first byte array
|
|
* const uint8_t *b: pointer to second byte array
|
|
* size_t len: length of the byte arrays
|
|
*
|
|
* Returns 0 if the byte arrays are equal, 1 otherwise
|
|
**************************************************/
|
|
int PQCLEAN_KYBER512_AVX2_verify(const uint8_t *a, const uint8_t *b, size_t len) {
|
|
size_t i;
|
|
uint64_t r;
|
|
__m256i f, g, h;
|
|
|
|
h = _mm256_setzero_si256();
|
|
for (i = 0; i < len / 32; i++) {
|
|
f = _mm256_loadu_si256((__m256i *)&a[32 * i]);
|
|
g = _mm256_loadu_si256((__m256i *)&b[32 * i]);
|
|
f = _mm256_xor_si256(f, g);
|
|
h = _mm256_or_si256(h, f);
|
|
}
|
|
r = 1 - _mm256_testz_si256(h, h);
|
|
|
|
a += 32 * i;
|
|
b += 32 * i;
|
|
len -= 32 * i;
|
|
for (i = 0; i < len; i++) {
|
|
r |= a[i] ^ b[i];
|
|
}
|
|
|
|
r = (-r) >> 63;
|
|
return r;
|
|
}
|
|
|
|
/*************************************************
|
|
* Name: PQCLEAN_KYBER512_AVX2_cmov
|
|
*
|
|
* Description: Copy len bytes from x to r if b is 1;
|
|
* don't modify x if b is 0. Requires b to be in {0,1};
|
|
* assumes two's complement representation of negative integers.
|
|
* Runs in constant time.
|
|
*
|
|
* Arguments: unsigned char *r: pointer to output byte array
|
|
* const unsigned char *x: pointer to input byte array
|
|
* size_t len: Amount of bytes to be copied
|
|
* unsigned char b: Condition bit; has to be in {0,1}
|
|
**************************************************/
|
|
void PQCLEAN_KYBER512_AVX2_cmov(uint8_t *restrict r, const uint8_t *x, size_t len, uint8_t b) {
|
|
size_t i;
|
|
__m256i xvec, rvec, bvec;
|
|
|
|
bvec = _mm256_set1_epi64x(-(uint64_t)b);
|
|
for (i = 0; i < len / 32; i++) {
|
|
rvec = _mm256_loadu_si256((__m256i *)&r[32 * i]);
|
|
xvec = _mm256_loadu_si256((__m256i *)&x[32 * i]);
|
|
rvec = _mm256_blendv_epi8(rvec, xvec, bvec);
|
|
_mm256_storeu_si256((__m256i *)&r[32 * i], rvec);
|
|
}
|
|
|
|
r += 32 * i;
|
|
x += 32 * i;
|
|
len -= 32 * i;
|
|
for (i = 0; i < len; i++) {
|
|
r[i] ^= -b & (x[i] ^ r[i]);
|
|
}
|
|
}
|