64 lines
1.9 KiB
C
64 lines
1.9 KiB
C
#include "api.h"
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#include "cmov.h"
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#include "fips202.h"
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#include "owcpa.h"
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#include "params.h"
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#include "randombytes.h"
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#include "sample.h"
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// API FUNCTIONS
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int PQCLEAN_NTRUHRSS701_CLEAN_crypto_kem_keypair(uint8_t *pk, uint8_t *sk) {
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uint8_t seed[NTRU_SAMPLE_FG_BYTES];
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randombytes(seed, NTRU_SAMPLE_FG_BYTES);
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PQCLEAN_NTRUHRSS701_CLEAN_owcpa_keypair(pk, sk, seed);
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randombytes(sk + NTRU_OWCPA_SECRETKEYBYTES, NTRU_PRFKEYBYTES);
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return 0;
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}
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int PQCLEAN_NTRUHRSS701_CLEAN_crypto_kem_enc(uint8_t *c, uint8_t *k, const uint8_t *pk) {
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poly r, m;
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uint8_t rm[NTRU_OWCPA_MSGBYTES];
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uint8_t rm_seed[NTRU_SAMPLE_RM_BYTES];
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randombytes(rm_seed, NTRU_SAMPLE_RM_BYTES);
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PQCLEAN_NTRUHRSS701_CLEAN_sample_rm(&r, &m, rm_seed);
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PQCLEAN_NTRUHRSS701_CLEAN_poly_S3_tobytes(rm, &r);
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PQCLEAN_NTRUHRSS701_CLEAN_poly_S3_tobytes(rm + NTRU_PACK_TRINARY_BYTES, &m);
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sha3_256(k, rm, NTRU_OWCPA_MSGBYTES);
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PQCLEAN_NTRUHRSS701_CLEAN_poly_Z3_to_Zq(&r);
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PQCLEAN_NTRUHRSS701_CLEAN_owcpa_enc(c, &r, &m, pk);
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return 0;
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}
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int PQCLEAN_NTRUHRSS701_CLEAN_crypto_kem_dec(uint8_t *k, const uint8_t *c, const uint8_t *sk) {
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int i, fail;
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uint8_t rm[NTRU_OWCPA_MSGBYTES];
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uint8_t buf[NTRU_PRFKEYBYTES + NTRU_CIPHERTEXTBYTES];
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fail = PQCLEAN_NTRUHRSS701_CLEAN_owcpa_dec(rm, c, sk);
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/* If fail = 0 then c = Enc(h, rm). There is no need to re-encapsulate. */
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/* See comment in PQCLEAN_NTRUHRSS701_CLEAN_owcpa_dec for details. */
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sha3_256(k, rm, NTRU_OWCPA_MSGBYTES);
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/* shake(secret PRF key || input ciphertext) */
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for (i = 0; i < NTRU_PRFKEYBYTES; i++) {
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buf[i] = sk[i + NTRU_OWCPA_SECRETKEYBYTES];
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}
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for (i = 0; i < NTRU_CIPHERTEXTBYTES; i++) {
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buf[NTRU_PRFKEYBYTES + i] = c[i];
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}
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sha3_256(rm, buf, NTRU_PRFKEYBYTES + NTRU_CIPHERTEXTBYTES);
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PQCLEAN_NTRUHRSS701_CLEAN_cmov(k, rm, NTRU_SHAREDKEYBYTES, (unsigned char) fail);
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return 0;
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}
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