libavutil/rc4.h

   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 */