RAND_add, RAND_seed, RAND_status, RAND_event, RAND_screen - add entropy to the
void RAND_seed(const void *buf, int num);
void RAND_add(const void *buf, int num, double entropy);
#if OPENSSL_API_COMPAT < 0x10100000L
int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam);
mixes the num
bytes at buf
into the PRNG state.
Thus, if the data at buf
are unpredictable to an adversary, this
increases the uncertainty about the state and makes the PRNG output less
predictable. Suitable input comes from user interaction (random key presses,
mouse movements) and certain hardware events. The entropy
(the lower bound of) an estimate of how much randomness is contained in
, measured in bytes. Details about sources of randomness and how to
estimate their entropy can be found in the literature, e.g. RFC 1750.
may be called with sensitive data such as user entered
passwords. The seed values cannot be recovered from the PRNG output.
OpenSSL makes sure that the PRNG state is unique for each thread. On systems
that provide "/dev/urandom", the randomness device is used to seed
the PRNG transparently. However, on all other systems, the application is
responsible for seeding the PRNG by calling RAND_add()
is equivalent to RAND_add()
when num ==
are deprecated and should not be
returns 1 if the PRNG has been seeded with enough data, 0
and returns RAND_status()
RAND_screen calls RAND_poll()
The other functions do not return values.
are deprecated since OpenSSL 1.1.0.
Use the functions described above instead.
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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