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pqcrypto/crypto_kem/ntruhps2048677/clean/sample.c

47 lines
1.8 KiB
C

#include "crypto_sort_int32.h"
#include "sample.h"
void PQCLEAN_NTRUHPS2048677_CLEAN_sample_fg(poly *f, poly *g, const unsigned char uniformbytes[NTRU_SAMPLE_FG_BYTES]) {
PQCLEAN_NTRUHPS2048677_CLEAN_sample_iid(f, uniformbytes);
PQCLEAN_NTRUHPS2048677_CLEAN_sample_fixed_type(g, uniformbytes + NTRU_SAMPLE_IID_BYTES);
}
void PQCLEAN_NTRUHPS2048677_CLEAN_sample_rm(poly *r, poly *m, const unsigned char uniformbytes[NTRU_SAMPLE_RM_BYTES]) {
PQCLEAN_NTRUHPS2048677_CLEAN_sample_iid(r, uniformbytes);
PQCLEAN_NTRUHPS2048677_CLEAN_sample_fixed_type(m, uniformbytes + NTRU_SAMPLE_IID_BYTES);
}
void PQCLEAN_NTRUHPS2048677_CLEAN_sample_fixed_type(poly *r, const unsigned char u[NTRU_SAMPLE_FT_BYTES]) {
// Assumes NTRU_SAMPLE_FT_BYTES = ceil(30*(n-1)/8)
int32_t s[NTRU_N - 1];
int i;
// Use 30 bits of u per word
for (i = 0; i < (NTRU_N - 1) / 4; i++) {
s[4 * i + 0] = (u[15 * i + 0] << 2) + (u[15 * i + 1] << 10) + (u[15 * i + 2] << 18) + ((uint32_t) u[15 * i + 3] << 26);
s[4 * i + 1] = ((u[15 * i + 3] & 0xc0) >> 4) + (u[15 * i + 4] << 4) + (u[15 * i + 5] << 12) + (u[15 * i + 6] << 20) + ((uint32_t) u[15 * i + 7] << 28);
s[4 * i + 2] = ((u[15 * i + 7] & 0xf0) >> 2) + (u[15 * i + 8] << 6) + (u[15 * i + 9] << 14) + (u[15 * i + 10] << 22) + ((uint32_t) u[15 * i + 11] << 30);
s[4 * i + 3] = (u[15 * i + 11] & 0xfc) + (u[15 * i + 12] << 8) + (u[15 * i + 13] << 15) + ((uint32_t) u[15 * i + 14] << 24);
}
for (i = 0; i < NTRU_WEIGHT / 2; i++) {
s[i] |= 1;
}
for (i = NTRU_WEIGHT / 2; i < NTRU_WEIGHT; i++) {
s[i] |= 2;
}
PQCLEAN_NTRUHPS2048677_CLEAN_crypto_sort_int32(s, NTRU_N - 1);
for (i = 0; i < NTRU_N - 1; i++) {
r->coeffs[i] = ((uint16_t) (s[i] & 3));
}
r->coeffs[NTRU_N - 1] = 0;
}