0d7743d576
* Update NTRU version: https://github.com/jschanck/ntru/tree/485dde03 * Fixed ntruhrss701/clean/Makefile.Microsoft_nmake
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
#include "poly.h"
|
|
|
|
static uint16_t mod3(uint16_t a) {
|
|
uint16_t r;
|
|
int16_t t, c;
|
|
|
|
r = (a >> 8) + (a & 0xff); // r mod 255 == a mod 255
|
|
r = (r >> 4) + (r & 0xf); // r' mod 15 == r mod 15
|
|
r = (r >> 2) + (r & 0x3); // r' mod 3 == r mod 3
|
|
r = (r >> 2) + (r & 0x3); // r' mod 3 == r mod 3
|
|
|
|
t = r - 3;
|
|
c = t >> 15;
|
|
|
|
return (c & r) ^ (~c & t);
|
|
}
|
|
|
|
void PQCLEAN_NTRUHPS2048677_CLEAN_poly_mod_3_Phi_n(poly *r) {
|
|
int i;
|
|
for (i = 0; i < NTRU_N; i++) {
|
|
r->coeffs[i] = mod3(r->coeffs[i] + 2 * r->coeffs[NTRU_N - 1]);
|
|
}
|
|
}
|
|
|
|
void PQCLEAN_NTRUHPS2048677_CLEAN_poly_mod_q_Phi_n(poly *r) {
|
|
int i;
|
|
for (i = 0; i < NTRU_N; i++) {
|
|
r->coeffs[i] = r->coeffs[i] - r->coeffs[NTRU_N - 1];
|
|
}
|
|
}
|
|
|
|
void PQCLEAN_NTRUHPS2048677_CLEAN_poly_Rq_to_S3(poly *r, const poly *a) {
|
|
/* NOTE: Assumes input is in [0,Q-1]^N */
|
|
/* Produces output in {0,1,2}^N */
|
|
int i;
|
|
|
|
/* Center coeffs around 3Q: [0, Q-1] -> [3Q - Q/2, 3Q + Q/2) */
|
|
for (i = 0; i < NTRU_N; i++) {
|
|
r->coeffs[i] = ((MODQ(a->coeffs[i]) >> (NTRU_LOGQ - 1)) ^ 3) << NTRU_LOGQ;
|
|
r->coeffs[i] += MODQ(a->coeffs[i]);
|
|
}
|
|
|
|
PQCLEAN_NTRUHPS2048677_CLEAN_poly_mod_3_Phi_n(r);
|
|
}
|
|
|