123 lines
2.4 KiB
C
123 lines
2.4 KiB
C
/*
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* Copyright (C) 2013-2016 Andreas Steffen
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* HSR Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include "ntru_trits.h"
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#include "ntru_convert.h"
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#include <crypto/xofs/xof_bitspender.h>
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#include <utils/debug.h>
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#include <utils/test.h>
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typedef struct private_ntru_trits_t private_ntru_trits_t;
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/**
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* Private data of an ntru_trits_t object.
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*/
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struct private_ntru_trits_t {
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/**
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* Public ntru_trits_t interface.
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*/
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ntru_trits_t public;
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/**
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* Size of the trits array
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*/
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size_t trits_len;
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/**
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* Array containing a trit per octet
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*/
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uint8_t *trits;
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};
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METHOD(ntru_trits_t, get_size, size_t,
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private_ntru_trits_t *this)
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{
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return this->trits_len;
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}
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METHOD(ntru_trits_t, get_trits, uint8_t*,
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private_ntru_trits_t *this)
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{
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return this->trits;
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}
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METHOD(ntru_trits_t, destroy, void,
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private_ntru_trits_t *this)
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{
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memwipe(this->trits, this->trits_len);
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free(this->trits);
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free(this);
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}
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/*
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* Described in header.
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*/
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ntru_trits_t *ntru_trits_create(size_t len, ext_out_function_t alg,
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chunk_t seed)
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{
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private_ntru_trits_t *this;
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uint8_t octet, buf[5], *trits;
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size_t trits_needed;
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xof_bitspender_t *bitspender;
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bitspender = xof_bitspender_create(alg, seed, TRUE);
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if (!bitspender)
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{
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return NULL;
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}
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INIT(this,
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.public = {
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.get_size = _get_size,
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.get_trits = _get_trits,
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.destroy = _destroy,
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},
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.trits_len = len,
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.trits = malloc(len),
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);
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trits = this->trits;
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trits_needed = this->trits_len;
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while (trits_needed > 0)
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{
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if (!bitspender->get_byte(bitspender, &octet))
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{
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bitspender->destroy(bitspender);
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destroy(this);
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return NULL;
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}
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if (octet < 243) /* 243 = 3^5 */
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{
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ntru_octet_2_trits(octet, (trits_needed < 5) ? buf : trits);
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if (trits_needed < 5)
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{
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memcpy(trits, buf, trits_needed);
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break;
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}
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trits += 5;
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trits_needed -= 5;
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}
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}
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bitspender->destroy(bitspender);
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return &this->public;
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}
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EXPORT_FUNCTION_FOR_TESTS(ntru, ntru_trits_create);
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