112 lines
2.6 KiB
C
112 lines
2.6 KiB
C
/*
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* Copyright (C) 2014 FH Bielefeld
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*
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* This file is part of a FH Bielefeld project.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*/
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/**
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* @file ntru_rnd.c
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* This file allows generation of random polynomials.
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* @brief random polynomials
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*/
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#include "ntru_err.h"
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#include "ntru_params.h"
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#include "ntru_poly.h"
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#include <fmpz_poly.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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/*------------------------------------------------------------------------*/
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int
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get_rnd_int(void)
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{
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int rnd_data = open("/dev/random", O_RDONLY);
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int rnd_int;
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size_t rnd_len = 0;
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while (rnd_len < sizeof(rnd_int)) {
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ssize_t result = read(rnd_data, ((char*)&rnd_int) + rnd_len,
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sizeof(rnd_int) - rnd_len);
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if (result < 0)
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NTRU_ABORT("Unable to read /dev/random!\n");
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rnd_len += result;
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}
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close(rnd_data);
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return rnd_int;
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}
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/*------------------------------------------------------------------------*/
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int
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get_urnd_int(void)
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{
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int rnd_data = open("/dev/urandom", O_RDONLY);
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int rnd_int;
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ssize_t result;
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result = read(rnd_data, ((char*)&rnd_int),
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sizeof(rnd_int));
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if (result < 0)
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NTRU_ABORT("Unable to read /dev/urandom!\n");
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close(rnd_data);
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return rnd_int;
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}
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/*------------------------------------------------------------------------*/
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void
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ntru_get_rnd_tern_poly_num(fmpz_poly_t poly,
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const ntru_params *params,
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uint32_t num_ones,
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uint32_t num_neg_ones,
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int (*rnd_int)(void))
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{
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if (!poly || ! params)
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NTRU_ABORT_DEBUG("unexpected NULL parameters");
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fmpz_poly_zero(poly);
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while (num_ones != 0 || num_neg_ones != 0) {
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int32_t pos = rnd_int() % params->N;
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if (!fmpz_cmp_si_n(fmpz_poly_get_coeff_ptr(poly, pos), 0)) {
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if (num_ones > 0) {
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fmpz_poly_set_coeff_si(poly, pos, 1);
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num_ones--;
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} else if (num_neg_ones > 0) {
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fmpz_poly_set_coeff_si(poly, pos, -1);
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num_neg_ones--;
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}
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}
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}
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}
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/*------------------------------------------------------------------------*/
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