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pqcrypto/crypto_kem/ntruhps2048509/avx2/kem.c
2021-03-24 21:02:48 +00:00

64 lines
2.0 KiB
C

#include "api.h"
#include "cmov.h"
#include "fips202.h"
#include "owcpa.h"
#include "params.h"
#include "randombytes.h"
#include "sample.h"
// API FUNCTIONS
int PQCLEAN_NTRUHPS2048509_AVX2_crypto_kem_keypair(uint8_t *pk, uint8_t *sk) {
uint8_t seed[NTRU_SAMPLE_FG_BYTES];
randombytes(seed, NTRU_SAMPLE_FG_BYTES);
PQCLEAN_NTRUHPS2048509_AVX2_owcpa_keypair(pk, sk, seed);
randombytes(sk + NTRU_OWCPA_SECRETKEYBYTES, NTRU_PRFKEYBYTES);
return 0;
}
int PQCLEAN_NTRUHPS2048509_AVX2_crypto_kem_enc(uint8_t *c, uint8_t *k, const uint8_t *pk) {
poly r, m;
uint8_t rm[NTRU_OWCPA_MSGBYTES];
uint8_t rm_seed[NTRU_SAMPLE_RM_BYTES];
randombytes(rm_seed, NTRU_SAMPLE_RM_BYTES);
PQCLEAN_NTRUHPS2048509_AVX2_sample_rm(&r, &m, rm_seed);
PQCLEAN_NTRUHPS2048509_AVX2_poly_S3_tobytes(rm, &r);
PQCLEAN_NTRUHPS2048509_AVX2_poly_S3_tobytes(rm + NTRU_PACK_TRINARY_BYTES, &m);
sha3_256(k, rm, NTRU_OWCPA_MSGBYTES);
PQCLEAN_NTRUHPS2048509_AVX2_poly_Z3_to_Zq(&r);
PQCLEAN_NTRUHPS2048509_AVX2_owcpa_enc(c, &r, &m, pk);
return 0;
}
int PQCLEAN_NTRUHPS2048509_AVX2_crypto_kem_dec(uint8_t *k, const uint8_t *c, const uint8_t *sk) {
int i, fail;
uint8_t rm[NTRU_OWCPA_MSGBYTES];
uint8_t buf[NTRU_PRFKEYBYTES + NTRU_CIPHERTEXTBYTES];
fail = PQCLEAN_NTRUHPS2048509_AVX2_owcpa_dec(rm, c, sk);
/* If fail = 0 then c = Enc(h, rm). There is no need to re-encapsulate. */
/* See comment in PQCLEAN_NTRUHPS2048509_AVX2_owcpa_dec for details. */
sha3_256(k, rm, NTRU_OWCPA_MSGBYTES);
/* shake(secret PRF key || input ciphertext) */
for (i = 0; i < NTRU_PRFKEYBYTES; i++) {
buf[i] = sk[i + NTRU_OWCPA_SECRETKEYBYTES];
}
for (i = 0; i < NTRU_CIPHERTEXTBYTES; i++) {
buf[NTRU_PRFKEYBYTES + i] = c[i];
}
sha3_256(rm, buf, NTRU_PRFKEYBYTES + NTRU_CIPHERTEXTBYTES);
PQCLEAN_NTRUHPS2048509_AVX2_cmov(k, rm, NTRU_SHAREDKEYBYTES, (unsigned char) fail);
return 0;
}