DragonFly On-Line Manual Pages
RAND(3) LibreSSL RAND(3)
RAND - pseudo-random number generator
int RAND_bytes(unsigned char *buf, int num);
int RAND_pseudo_bytes(unsigned char *buf, int num);
These functions give access to the systems cryptographically secure
pseudo-random number generator (PRNG). It is used by other library
functions for example to generate random keys, and applications can use
it when they need randomness.
RAND_bytes(3) describes how to obtain random data from the PRNG.
The RAND_SSLeay() method implements a PRNG based on the systems'
arc4random_buf(3) random number generator.
LibreSSL 2017-01-09 RAND(3)
RAND_load_file(3) OpenSSL RAND_load_file(3)
RAND_load_file, RAND_write_file, RAND_file_name - PRNG seed file
const char *RAND_file_name(char *buf, size_t num);
int RAND_load_file(const char *filename, long max_bytes);
int RAND_write_file(const char *filename);
RAND_file_name() generates a default path for the random seed file. buf
points to a buffer of size num in which to store the filename. The seed
file is $RANDFILE if that environment variable is set, $HOME/.rnd
otherwise. If $HOME is not set either, or num is too small for the path
name, an error occurs.
RAND_load_file() reads a number of bytes from file filename and adds
them to the PRNG. If max_bytes is non-negative, up to to max_bytes are
read; starting with OpenSSL 0.9.5, if max_bytes is -1, the complete
file is read.
RAND_write_file() writes a number of random bytes (currently 1024) to
file filename which can be used to initialize the PRNG by calling
RAND_load_file() in a later session.
RAND_load_file() returns the number of bytes read.
RAND_write_file() returns the number of bytes written, and -1 if the
bytes written were generated without appropriate seed.
RAND_file_name() returns a pointer to buf on success, and NULL on
rand(3), RAND_add(3), RAND_cleanup(3)
RAND_load_file(), RAND_write_file() and RAND_file_name() are available
in all versions of SSLeay and OpenSSL.
1.0.2h 2016-05-03 RAND_load_file(3)