libavutil/aes_ctr.h

   1 /*
   2  * AES-CTR cipher
   3  * Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #ifndef AVUTIL_AES_CTR_H
  23 #define AVUTIL_AES_CTR_H
  24
  25 #include <stdint.h>
  26
  27 #include "attributes.h"
  28
  29 #define AES_CTR_KEY_SIZE (16)
  30 #define AES_CTR_IV_SIZE (8)
  31
  32 struct AVAESCTR;
  33
  34 /**
  35  * Allocate an AVAESCTR context.
  36  */
  37 struct AVAESCTR *av_aes_ctr_alloc(void);
  38
  39 /**
  40  * Initialize an AVAESCTR context.
  41  * @param key encryption key, must have a length of AES_CTR_KEY_SIZE
  42  */
  43 int av_aes_ctr_init(struct AVAESCTR *a, const uint8_t *key);
  44
  45 /**
  46  * Release an AVAESCTR context.
  47  */
  48 void av_aes_ctr_free(struct AVAESCTR *a);
  49
  50 /**
  51  * Process a buffer using a previously initialized context.
  52  * @param dst destination array, can be equal to src
  53  * @param src source array, can be equal to dst
  54  * @param size the size of src and dst
  55  */
  56 void av_aes_ctr_crypt(struct AVAESCTR *a, uint8_t *dst, const uint8_t *src, int size);
  57
  58 /**
  59  * Get the current iv
  60  */
  61 const uint8_t* av_aes_ctr_get_iv(struct AVAESCTR *a);
  62
  63 /**
  64  * Generate a random iv
  65  */
  66 void av_aes_ctr_set_random_iv(struct AVAESCTR *a);
  67
  68 /**
  69  * Forcefully change the 8-byte iv
  70  */
  71 void av_aes_ctr_set_iv(struct AVAESCTR *a, const uint8_t* iv);
  72
  73 /**
  74  * Forcefully change the "full" 16-byte iv, including the counter
  75  */
  76 void av_aes_ctr_set_full_iv(struct AVAESCTR *a, const uint8_t* iv);
  77
  78 /**
  79  * Increment the top 64 bit of the iv (performed after each frame)
  80  */
  81 void av_aes_ctr_increment_iv(struct AVAESCTR *a);
  82
  83 /**
  84  * @}
  85  */
  86
  87 #endif /* AVUTIL_AES_CTR_H */