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 /** 27 * @defgroup lavu_rc4 RC4 28 * @ingroup lavu_crypto 29 * @{ 30 */ 31 32 typedef struct AVRC4 { 33 uint8_t state[256]; 34 int x, y; 35 } AVRC4; 36 37 /** 38 * Allocate an AVRC4 context. 39 */ 40 AVRC4 *av_rc4_alloc(void); 41 42 /** 43 * @brief Initializes an AVRC4 context. 44 * 45 * @param key_bits must be a multiple of 8 46 * @param decrypt 0 for encryption, 1 for decryption, currently has no effect 47 * @return zero on success, negative value otherwise 48 */ 49 int av_rc4_init(struct AVRC4 *d, const uint8_t *key, int key_bits, int decrypt); 50 51 /** 52 * @brief Encrypts / decrypts using the RC4 algorithm. 53 * 54 * @param count number of bytes 55 * @param dst destination array, can be equal to src 56 * @param src source array, can be equal to dst, may be NULL 57 * @param iv not (yet) used for RC4, should be NULL 58 * @param decrypt 0 for encryption, 1 for decryption, not (yet) used 59 */ 60 void av_rc4_crypt(struct AVRC4 *d, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt); 61 62 /** 63 * @} 64 */ 65 66 #endif /* AVUTIL_RC4_H */ 67