#include <openssl/rand.h> int RAND_status(void); int RAND_poll(); void RAND_add(const void *buf, int num, double randomness); void RAND_seed(const void *buf, int num); void RAND_keep_random_devices_open(int keep);
#if OPENSSL_API_COMPAT < 0x10100000L int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam); void RAND_screen(void); #endif
RAND_status() indicates whether or not the random generator has been sufficiently seeded. If not, functions such as RAND_bytes(3) will fail.
RAND_poll() uses the system's capabilities to seed the random generator using random input obtained from polling various trusted entropy sources. The default choice of the entropy source can be modified at build time, see RAND(7) for more details.
RAND_add() mixes the num bytes at buf into the internal state of the random generator. This function will not normally be needed, as mentioned above. The randomness argument is an estimate of how much randomness is contained in buf, in bytes, and should be a number between zero and num. Details about sources of randomness and how to estimate their randomness can be found in the literature; for example [NIST SP 800-90B]. The content of buf cannot be recovered from subsequent random generator output. Applications that intend to save and restore random state in an external file should consider using RAND_load_file(3) instead.
RAND_seed() is equivalent to RAND_add() with randomness set to num.
RAND_keep_random_devices_open() is used to control file descriptor usage by the random seed sources. Some seed sources maintain open file descriptors by default, which allows such sources to operate in a chroot(2) jail without the associated device nodes being available. When the keep argument is zero, this call disables the retention of file descriptors. Conversely, a non-zero argument enables the retention of file descriptors. This function is usually called during initialization and it takes effect immediately.
RAND_poll() returns 1 if it generated seed data, 0 otherwise.
RAND_event() returns RAND_status().
Licensed under the OpenSSL license (the ``License''). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.