93 lines
3.6 KiB
C
93 lines
3.6 KiB
C
#include "api.h"
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#include "niederreiter.h"
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#include "randombytes.h"
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#include "rng.h"
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#include <string.h>
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static void pack_pk(uint8_t *pk_bytes, publicKeyNiederreiter_t *pk) {
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size_t i;
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for (i = 0; i < N0 - 1; i++) {
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PQCLEAN_LEDAKEMLT32_LEAKTIME_gf2x_tobytes(pk_bytes + i * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B,
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pk->Mtr + i * NUM_DIGITS_GF2X_ELEMENT);
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}
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}
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static void unpack_pk(publicKeyNiederreiter_t *pk, const uint8_t *pk_bytes) {
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size_t i;
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for (i = 0; i < N0 - 1; i++) {
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PQCLEAN_LEDAKEMLT32_LEAKTIME_gf2x_frombytes(pk->Mtr + i * NUM_DIGITS_GF2X_ELEMENT,
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pk_bytes + i * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B);
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}
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}
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static void pack_ct(uint8_t *sk_bytes, DIGIT *ct) {
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PQCLEAN_LEDAKEMLT32_LEAKTIME_gf2x_tobytes(sk_bytes, ct);
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}
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static void unpack_ct(DIGIT *ct, const uint8_t *ct_bytes) {
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PQCLEAN_LEDAKEMLT32_LEAKTIME_gf2x_frombytes(ct, ct_bytes);
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}
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static void pack_error(uint8_t *error_bytes, DIGIT *error_digits) {
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size_t i;
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for (i = 0; i < N0; i++) {
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PQCLEAN_LEDAKEMLT32_LEAKTIME_gf2x_tobytes(error_bytes + i * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B,
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error_digits + i * NUM_DIGITS_GF2X_ELEMENT);
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}
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}
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/* Generates a keypair - pk is the public key and sk is the secret key. */
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int PQCLEAN_LEDAKEMLT32_LEAKTIME_crypto_kem_keypair(unsigned char *pk, unsigned char *sk) {
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AES_XOF_struct niederreiter_keys_expander;
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publicKeyNiederreiter_t pk_nie;
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randombytes(((privateKeyNiederreiter_t *)sk)->prng_seed, TRNG_BYTE_LENGTH);
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PQCLEAN_LEDAKEMLT32_LEAKTIME_seedexpander_from_trng(&niederreiter_keys_expander, ((privateKeyNiederreiter_t *)sk)->prng_seed);
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PQCLEAN_LEDAKEMLT32_LEAKTIME_niederreiter_keygen(&pk_nie, (privateKeyNiederreiter_t *) sk, &niederreiter_keys_expander);
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pack_pk(pk, &pk_nie);
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return 0;
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}
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/* Encrypt - pk is the public key, ct is a key encapsulation message
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(ciphertext), ss is the shared secret.*/
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int PQCLEAN_LEDAKEMLT32_LEAKTIME_crypto_kem_enc(unsigned char *ct, unsigned char *ss, const unsigned char *pk) {
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AES_XOF_struct niederreiter_encap_key_expander;
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unsigned char encapsulated_key_seed[TRNG_BYTE_LENGTH];
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DIGIT error_vector[N0 * NUM_DIGITS_GF2X_ELEMENT];
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uint8_t error_bytes[N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B];
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DIGIT syndrome[NUM_DIGITS_GF2X_ELEMENT];
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publicKeyNiederreiter_t pk_nie;
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randombytes(encapsulated_key_seed, TRNG_BYTE_LENGTH);
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unpack_pk(&pk_nie, pk);
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PQCLEAN_LEDAKEMLT32_LEAKTIME_seedexpander_from_trng(&niederreiter_encap_key_expander, encapsulated_key_seed);
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PQCLEAN_LEDAKEMLT32_LEAKTIME_rand_circulant_blocks_sequence(error_vector, &niederreiter_encap_key_expander);
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pack_error(error_bytes, error_vector);
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HASH_FUNCTION(ss, error_bytes, (N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B));
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PQCLEAN_LEDAKEMLT32_LEAKTIME_niederreiter_encrypt(syndrome, &pk_nie, error_vector);
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pack_ct(ct, syndrome);
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return 0;
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}
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/* Decrypt - ct is a key encapsulation message (ciphertext), sk is the private
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key, ss is the shared secret */
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int PQCLEAN_LEDAKEMLT32_LEAKTIME_crypto_kem_dec(unsigned char *ss, const unsigned char *ct, const unsigned char *sk) {
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DIGIT decoded_error_vector[N0 * NUM_DIGITS_GF2X_ELEMENT];
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uint8_t decoded_error_bytes[N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B];
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DIGIT syndrome[NUM_DIGITS_GF2X_ELEMENT];
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unpack_ct(syndrome, ct);
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PQCLEAN_LEDAKEMLT32_LEAKTIME_niederreiter_decrypt(decoded_error_vector, (privateKeyNiederreiter_t *)sk, syndrome);
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pack_error(decoded_error_bytes, decoded_error_vector);
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HASH_FUNCTION(ss, decoded_error_bytes, (N0 * NUM_DIGITS_GF2X_ELEMENT * DIGIT_SIZE_B));
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return 0;
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}
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