random_seed.h (1889B)
1 /* 2 * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com> 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_RANDOM_SEED_H 22 #define AVUTIL_RANDOM_SEED_H 23 24 #include <stddef.h> 25 #include <stdint.h> 26 /** 27 * @addtogroup lavu_crypto 28 * @{ 29 */ 30 31 /** 32 * Get a seed to use in conjunction with random functions. 33 * This function tries to provide a good seed at a best effort bases. 34 * Its possible to call this function multiple times if more bits are needed. 35 * It can be quite slow, which is why it should only be used as seed for a faster 36 * PRNG. The quality of the seed depends on the platform. 37 */ 38 uint32_t av_get_random_seed(void); 39 40 /** 41 * Generate cryptographically secure random data, i.e. suitable for use as 42 * encryption keys and similar. 43 * 44 * @param buf buffer into which the random data will be written 45 * @param len size of buf in bytes 46 * 47 * @retval 0 success, len bytes of random data was written 48 * into buf 49 * @retval "a negative AVERROR code" random data could not be generated 50 */ 51 int av_random_bytes(uint8_t *buf, size_t len); 52 53 /** 54 * @} 55 */ 56 57 #endif /* AVUTIL_RANDOM_SEED_H */