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 */ 88