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rc4.h
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1 /*
2  * RC4 encryption/decryption/pseudo-random number generator
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVUTIL_RC4_H
22 #define AVUTIL_RC4_H
23 
24 #include <stdint.h>
25 
26 struct AVRC4 {
27  uint8_t state[256];
28  int x, y;
29 };
30 
31 /**
32  * @brief Initializes an AVRC4 context.
33  *
34  * @param key_bits must be a multiple of 8
35  * @param decrypt 0 for encryption, 1 for decryption, currently has no effect
36  */
37 int av_rc4_init(struct AVRC4 *d, const uint8_t *key, int key_bits, int decrypt);
38 
39 /**
40  * @brief Encrypts / decrypts using the RC4 algorithm.
41  *
42  * @param count number of bytes
43  * @param dst destination array, can be equal to src
44  * @param src source array, can be equal to dst, may be NULL
45  * @param iv not (yet) used for RC4, should be NULL
46  * @param decrypt 0 for encryption, 1 for decryption, not (yet) used
47  */
48 void av_rc4_crypt(struct AVRC4 *d, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt);
49 
50 #endif /* AVUTIL_RC4_H */