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/*
* Copyright (C) 2016 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 "sha3_shake.h"
#include "sha3_keccak.h"
typedef struct private_sha3_shake_t private_sha3_shake_t;
/**
* Private data structure with hashing context for SHA-3
*/
struct private_sha3_shake_t {
/**
* Public interface for this hasher.
*/
sha3_shake_t public;
/**
* XOF algorithm to be used (XOF_SHAKE_128 or XOF_SHAKE_256)
*/
ext_out_function_t algorithm;
/**
* SHA-3 Keccak state
*/
sha3_keccak_t *keccak;
/**
* Capacity in bytes of the SHA-3 Keccak state
*/
u_int capacity;
};
METHOD(xof_t, get_type, ext_out_function_t,
private_sha3_shake_t *this)
{
return this->algorithm;
}
METHOD(xof_t, get_bytes, bool,
private_sha3_shake_t *this, size_t out_len, uint8_t *buffer)
{
this->keccak->squeeze(this->keccak, out_len, buffer);
return TRUE;
}
METHOD(xof_t, allocate_bytes, bool,
private_sha3_shake_t *this, size_t out_len, chunk_t *chunk)
{
*chunk = chunk_alloc(out_len);
this->keccak->squeeze(this->keccak, out_len, chunk->ptr);
return TRUE;
}
METHOD(xof_t, get_block_size, size_t,
private_sha3_shake_t *this)
{
return this->keccak->get_rate(this->keccak);
}
METHOD(xof_t, get_seed_size, size_t,
private_sha3_shake_t *this)
{
return this->capacity;
}
METHOD(xof_t, set_seed, bool,
private_sha3_shake_t *this, chunk_t seed)
{
this->keccak->reset(this->keccak);
this->keccak->absorb(this->keccak, seed);
this->keccak->finalize(this->keccak);
return TRUE;
}
METHOD(xof_t, destroy, void,
private_sha3_shake_t *this)
{
this->keccak->destroy(this->keccak);
free(this);
}
/*
* Described in header.
*/
sha3_shake_t* sha3_shake_create(ext_out_function_t algorithm)
{
private_sha3_shake_t *this;
u_int capacity = 0;
switch (algorithm)
{
case XOF_SHAKE_128:
capacity = 32;
break;
case XOF_SHAKE_256:
capacity = 64;
break;
default:
return NULL;
}
INIT(this,
.public = {
.xof_interface = {
.get_type = _get_type,
.get_bytes = _get_bytes,
.allocate_bytes = _allocate_bytes,
.get_block_size = _get_block_size,
.get_seed_size = _get_seed_size,
.set_seed = _set_seed,
.destroy = _destroy,
},
},
.algorithm = algorithm,
.capacity = capacity,
);
this->keccak = sha3_keccak_create(capacity, 0x1f);
if (!this->keccak)
{
free(this);
return NULL;
}
return &this->public;
}
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