pqc/crypto_kem/ntruhps4096821/clean/packq.c
John Schanck 4ea4b478ba
Update NTRU (#311)
* Update NTRU

version: https://github.com/jschanck/ntru/tree/485dde03

* Fixed ntruhrss701/clean/Makefile.Microsoft_nmake
2020-08-15 14:26:25 -04:00

37 lines
1.3 KiB
C

#include "poly.h"
void PQCLEAN_NTRUHPS4096821_CLEAN_poly_Sq_tobytes(unsigned char *r, const poly *a) {
int i;
for (i = 0; i < NTRU_PACK_DEG / 2; i++) {
r[3 * i + 0] = (unsigned char) ( MODQ(a->coeffs[2 * i + 0]) & 0xff);
r[3 * i + 1] = (unsigned char) ((MODQ(a->coeffs[2 * i + 0]) >> 8) | ((MODQ(a->coeffs[2 * i + 1]) & 0x0f) << 4));
r[3 * i + 2] = (unsigned char) ((MODQ(a->coeffs[2 * i + 1]) >> 4));
}
}
void PQCLEAN_NTRUHPS4096821_CLEAN_poly_Sq_frombytes(poly *r, const unsigned char *a) {
int i;
for (i = 0; i < NTRU_PACK_DEG / 2; i++) {
r->coeffs[2 * i + 0] = (a[3 * i + 0] >> 0) | (((uint16_t)a[3 * i + 1] & 0x0f) << 8);
r->coeffs[2 * i + 1] = (a[3 * i + 1] >> 4) | (((uint16_t)a[3 * i + 2] & 0xff) << 4);
}
r->coeffs[NTRU_N - 1] = 0;
}
void PQCLEAN_NTRUHPS4096821_CLEAN_poly_Rq_sum_zero_tobytes(unsigned char *r, const poly *a) {
PQCLEAN_NTRUHPS4096821_CLEAN_poly_Sq_tobytes(r, a);
}
void PQCLEAN_NTRUHPS4096821_CLEAN_poly_Rq_sum_zero_frombytes(poly *r, const unsigned char *a) {
int i;
PQCLEAN_NTRUHPS4096821_CLEAN_poly_Sq_frombytes(r, a);
/* Set r[n-1] so that the sum of coefficients is zero mod q */
r->coeffs[NTRU_N - 1] = 0;
for (i = 0; i < NTRU_PACK_DEG; i++) {
r->coeffs[NTRU_N - 1] -= r->coeffs[i];
}
}