pqc/src/encrypt.c

85 lines
1.9 KiB
C

/*
* Copyright (C) 2014 FH Bielefeld
*
* This file is part of a FH Bielefeld project.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*/
/**
* @file encrypt.c
* This file handles the NTRU encryption
* algorithm.
* @brief NTRU encryption
*/
#include "ascii_poly.h"
#include "encrypt.h"
#include "mem.h"
#include "ntru_string.h"
#include <string.h>
#include <fmpz_poly.h>
#include <fmpz.h>
void
ntru_encrypt_poly(
fmpz_poly_t msg_tern,
fmpz_poly_t pub_key,
fmpz_poly_t rnd,
fmpz_poly_t out,
ntru_context *ctx)
{
/* allow aliasing */
fmpz_poly_t tmp_poly_msg;
fmpz_poly_init(tmp_poly_msg);
fmpz_poly_set(tmp_poly_msg, msg_tern);
fmpz_poly_zero(out);
poly_starmultiply(pub_key, rnd, out, ctx, ctx->q);
fmpz_poly_add(out, out, tmp_poly_msg);
fmpz_poly_mod_unsigned(out, ctx->q);
fmpz_poly_clear(tmp_poly_msg);
}
string *
ntru_encrypt_string(
char *msg,
fmpz_poly_t pub_key,
fmpz_poly_t rnd,
ntru_context *ctx)
{
uint32_t i = 0;
string *enc_msg;
fmpz_poly_t **poly_array;
poly_array = ascii_to_tern_poly_arr(msg, ctx);
while (*poly_array[i]) {
ntru_encrypt_poly(*poly_array[i], pub_key, rnd, *poly_array[i], ctx);
i++;
}
enc_msg = poly_arr_to_ascii(poly_array, ctx);
poly_delete_array(poly_array);
return enc_msg;
}