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/*

 * AES-CTR cipher

 * Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com>

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#ifndef AVUTIL_AES_CTR_H
#define AVUTIL_AES_CTR_H

/**

 * @defgroup lavu_aes_ctr AES-CTR

 * @ingroup lavu_crypto

 * @{

 */

#include <stdint.h>

#include "attributes.h"

#define AES_CTR_KEY_SIZE (16)
#define AES_CTR_IV_SIZE (8)

struct AVAESCTR;

/**

 * Allocate an AVAESCTR context.

 */
struct AVAESCTR *av_aes_ctr_alloc(void);

/**

 * Initialize an AVAESCTR context.

 *

 * @param a The AVAESCTR context to initialize

 * @param key encryption key, must have a length of AES_CTR_KEY_SIZE

 */
int av_aes_ctr_init(struct AVAESCTR *a, const uint8_t *key);

/**

 * Release an AVAESCTR context.

 *

 * @param a The AVAESCTR context

 */
void av_aes_ctr_free(struct AVAESCTR *a);

/**

 * Process a buffer using a previously initialized context.

 *

 * @param a The AVAESCTR context

 * @param dst destination array, can be equal to src

 * @param src source array, can be equal to dst

 * @param size the size of src and dst

 */
void av_aes_ctr_crypt(struct AVAESCTR *a, uint8_t *dst, const uint8_t *src, int size);

/**

 * Get the current iv

 */
const uint8_t* av_aes_ctr_get_iv(struct AVAESCTR *a);

/**

 * Generate a random iv

 */
void av_aes_ctr_set_random_iv(struct AVAESCTR *a);

/**

 * Forcefully change the 8-byte iv

 */
void av_aes_ctr_set_iv(struct AVAESCTR *a, const uint8_t* iv);

/**

 * Forcefully change the "full" 16-byte iv, including the counter

 */
void av_aes_ctr_set_full_iv(struct AVAESCTR *a, const uint8_t* iv);

/**

 * Increment the top 64 bit of the iv (performed after each frame)

 */
void av_aes_ctr_increment_iv(struct AVAESCTR *a);

/**

 * @}

 */

#endif /* AVUTIL_AES_CTR_H */