FFmpeg
aes_ctr.h
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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 #include "version.h"
29 
30 #define AES_CTR_KEY_SIZE (16)
31 #define AES_CTR_IV_SIZE (8)
32 
33 struct AVAESCTR;
34 
35 /**
36  * Allocate an AVAESCTR context.
37  */
38 struct AVAESCTR *av_aes_ctr_alloc(void);
39 
40 /**
41  * Initialize an AVAESCTR context.
42  * @param key encryption key, must have a length of AES_CTR_KEY_SIZE
43  */
44 int av_aes_ctr_init(struct AVAESCTR *a, const uint8_t *key);
45 
46 /**
47  * Release an AVAESCTR context.
48  */
49 void av_aes_ctr_free(struct AVAESCTR *a);
50 
51 /**
52  * Process a buffer using a previously initialized context.
53  * @param dst destination array, can be equal to src
54  * @param src source array, can be equal to dst
55  * @param size the size of src and dst
56  */
57 void av_aes_ctr_crypt(struct AVAESCTR *a, uint8_t *dst, const uint8_t *src, int size);
58 
59 /**
60  * Get the current iv
61  */
62 const uint8_t* av_aes_ctr_get_iv(struct AVAESCTR *a);
63 
64 /**
65  * Generate a random iv
66  */
67 void av_aes_ctr_set_random_iv(struct AVAESCTR *a);
68 
69 /**
70  * Forcefully change the 8-byte iv
71  */
72 void av_aes_ctr_set_iv(struct AVAESCTR *a, const uint8_t* iv);
73 
74 /**
75  * Forcefully change the "full" 16-byte iv, including the counter
76  */
77 void av_aes_ctr_set_full_iv(struct AVAESCTR *a, const uint8_t* iv);
78 
79 /**
80  * Increment the top 64 bit of the iv (performed after each frame)
81  */
82 void av_aes_ctr_increment_iv(struct AVAESCTR *a);
83 
84 /**
85  * @}
86  */
87 
88 #endif /* AVUTIL_AES_CTR_H */
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:36
const char * key
#define src
Definition: vp8dsp.c:254
Macro definitions for various function/variable attributes.
const uint8_t * av_aes_ctr_get_iv(struct AVAESCTR *a)
Get the current iv.
Definition: aes_ctr.c:54
uint8_t
int av_aes_ctr_init(struct AVAESCTR *a, const uint8_t *key)
Initialize an AVAESCTR context.
Definition: aes_ctr.c:69
ptrdiff_t size
Definition: opengl_enc.c:100
struct AVAESCTR * av_aes_ctr_alloc(void)
Allocate an AVAESCTR context.
Definition: aes_ctr.c:36
Libavutil version macros.
void av_aes_ctr_set_random_iv(struct AVAESCTR *a)
Generate a random iv.
Definition: aes_ctr.c:59
void av_aes_ctr_crypt(struct AVAESCTR *a, uint8_t *dst, const uint8_t *src, int size)
Process a buffer using a previously initialized context.
Definition: aes_ctr.c:111
void av_aes_ctr_free(struct AVAESCTR *a)
Release an AVAESCTR context.
Definition: aes_ctr.c:84
void av_aes_ctr_set_full_iv(struct AVAESCTR *a, const uint8_t *iv)
Forcefully change the "full" 16-byte iv, including the counter.
Definition: aes_ctr.c:48
void av_aes_ctr_set_iv(struct AVAESCTR *a, const uint8_t *iv)
Forcefully change the 8-byte iv.
Definition: aes_ctr.c:41
void av_aes_ctr_increment_iv(struct AVAESCTR *a)
Increment the top 64 bit of the iv (performed after each frame)
Definition: aes_ctr.c:104