/* magma.c - GOST R 34.12-2015 (Magma) cipher implementation

 *

 * Copyright: 2017 Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the

 * "Software"), to deal in the Software without restriction, including

 * without limitation the rights to use, copy, modify, merge, publish,

 * distribute, sublicense, and/or sell copies of the Software, and to

 * permit persons to whom the Software is furnished to do so, subject to

 * the following conditions:

 *

 * The above copyright notice and this permission notice shall be included

 * in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY

 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,

 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE

 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 */

#if HAVE_CONFIG_H

#include "config.h"

#endif

#ifndef HAVE_NETTLE_MAGMA_SET_KEY

#include <assert.h>

#include <nettle/macros.h>

#include "nettle-write.h"

#include "magma.h"

#ifndef HAVE_NETTLE_GOST28147_SET_KEY

#include "gost28147.h"

#else

#include <nettle/gost28147.h>

#endif

void magma_set_key(struct magma_ctx *ctx, const uint8_t *key)

{

  unsigned i;

  for (i = 0; i < 8; i++, key += 4)

    ctx->key[i] = READ_UINT32(key);

}

void magma_encrypt(const struct magma_ctx *ctx, size_t length, uint8_t *dst,

       const uint8_t *src)

{

  uint32_t block[2];

  assert(!(length % MAGMA_BLOCK_SIZE));

  while (length) {

    block[1] = READ_UINT32(src);

    src += 4;

    block[0] = READ_UINT32(src);

    src += 4;

    gost28147_encrypt_simple(ctx->key, gost28147_param_TC26_Z.sbox,

           block, block);

    WRITE_UINT32(dst, block[1]);

    dst += 4;

    WRITE_UINT32(dst, block[0]);

    dst += 4;

    length -= MAGMA_BLOCK_SIZE;

  }

}

void magma_decrypt(const struct magma_ctx *ctx, size_t length, uint8_t *dst,

       const uint8_t *src)

{

  uint32_t block[2];

  assert(!(length % MAGMA_BLOCK_SIZE));

  while (length) {

    block[1] = READ_UINT32(src);

    src += 4;

    block[0] = READ_UINT32(src);

    src += 4;

    gost28147_decrypt_simple(ctx->key, gost28147_param_TC26_Z.sbox,

           block, block);

    WRITE_UINT32(dst, block[1]);

    dst += 4;

    WRITE_UINT32(dst, block[0]);

    dst += 4;

    length -= MAGMA_BLOCK_SIZE;

  }

}

#endif /* HAVE_NETTLE_MAGMA_SET_KEY */