RAND_egd, RAND_egd_bytes, RAND_query_egd_bytes - query entropy gathering daemon
#include <openssl/rand.h>
int RAND_egd_bytes(const char *path, int num);
int RAND_egd(const char *path);
int RAND_query_egd_bytes(const char *path, unsigned char *buf, int num);
On older platforms without a good source of randomness such as
"/dev/urandom", it is possible to query an Entropy Gathering Daemon
(EGD) over a local socket to obtain randomness and seed the OpenSSL RNG. The
protocol used is defined by the EGDs available at
<
http://egd.sourceforge.net/> or <
http://prngd.sourceforge.net>.
RAND_egd_bytes() requests
num bytes of randomness from an EGD at
the specified socket
path, and passes the data it receives into
RAND_add().
RAND_egd() is equivalent to
RAND_egd_bytes()
with
num set to 255.
RAND_query_egd_bytes() requests
num bytes of randomness from an
EGD at the specified socket
path, where
num must be less than
256. If
buf is
NULL, it is equivalent to
RAND_egd_bytes(). If
buf is not
NULL, then the data is
copied to the buffer and
RAND_add() is not called.
OpenSSL can be configured at build time to try to use the EGD for seeding
automatically.
RAND_egd() and
RAND_egd_bytes() return the number of bytes read
from the daemon on success, or -1 if the connection failed or the daemon did
not return enough data to fully seed the PRNG.
RAND_query_egd_bytes() returns the number of bytes read from the daemon
on success, or -1 if the connection failed.
RAND_add(3),
RAND_bytes(3),
RAND(7)
Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (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>.