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/*
* Copyright (C) 2013-2014 Andreas Steffen
* HSR Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program 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 General Public License
* for more details.
*/
#include "ntru_trits.h"
#include "ntru_convert.h"
#include <crypto/mgf1/mgf1_bitspender.h>
#include <utils/debug.h>
#include <utils/test.h>
typedef struct private_ntru_trits_t private_ntru_trits_t;
/**
* Private data of an ntru_trits_t object.
*/
struct private_ntru_trits_t {
/**
* Public ntru_trits_t interface.
*/
ntru_trits_t public;
/**
* Size of the trits array
*/
size_t trits_len;
/**
* Array containing a trit per octet
*/
uint8_t *trits;
};
METHOD(ntru_trits_t, get_size, size_t,
private_ntru_trits_t *this)
{
return this->trits_len;
}
METHOD(ntru_trits_t, get_trits, uint8_t*,
private_ntru_trits_t *this)
{
return this->trits;
}
METHOD(ntru_trits_t, destroy, void,
private_ntru_trits_t *this)
{
memwipe(this->trits, this->trits_len);
free(this->trits);
free(this);
}
/*
* Described in header.
*/
ntru_trits_t *ntru_trits_create(size_t len, hash_algorithm_t alg, chunk_t seed)
{
private_ntru_trits_t *this;
uint8_t octet, buf[5], *trits;
size_t trits_needed;
mgf1_bitspender_t *bitspender;
bitspender = mgf1_bitspender_create(alg, seed, TRUE);
if (!bitspender)
{
return NULL;
}
INIT(this,
.public = {
.get_size = _get_size,
.get_trits = _get_trits,
.destroy = _destroy,
},
.trits_len = len,
.trits = malloc(len),
);
trits = this->trits;
trits_needed = this->trits_len;
while (trits_needed > 0)
{
if (!bitspender->get_byte(bitspender, &octet))
{
bitspender->destroy(bitspender);
destroy(this);
return NULL;
}
if (octet < 243) /* 243 = 3^5 */
{
ntru_octet_2_trits(octet, (trits_needed < 5) ? buf : trits);
if (trits_needed < 5)
{
memcpy(trits, buf, trits_needed);
break;
}
trits += 5;
trits_needed -= 5;
}
}
bitspender->destroy(bitspender);
return &this->public;
}
EXPORT_FUNCTION_FOR_TESTS(ntru, ntru_trits_create);
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