-rw-r--r-- 647 saferewrite-20240622/src/cmp_64xint16/frodo2/verify.c raw
#include <stddef.h>
#include <stdint.h>
// ct_verify copied from
// 2020.06.18 version of official frodo src/util.c
// https://github.com/microsoft/PQCrypto-LWEKE/blob/155c24c3df47be6d5d9845fea37be110945e963c/src/util.c
int8_t ct_verify(const uint16_t *a, const uint16_t *b, size_t len)
{ // Compare two arrays in constant time.
// Returns 0 if the byte arrays are equal, -1 otherwise.
uint16_t r = 0;
for (size_t i = 0; i < len; i++) {
r |= a[i] ^ b[i];
}
r = (-(int16_t)r) >> (8*sizeof(uint16_t)-1);
return (int8_t)r;
}
int cmp_64xint16(const uint16_t *x,const uint16_t *y)
{
return ct_verify(x,y,64);
}