oracular (3) RAND_egd_bytes.3ssl.gz

Provided by: libssl-doc_3.3.1-2ubuntu2.1_all bug

NAME
       RAND_egd, RAND_egd_bytes, RAND_query_egd_bytes - query entropy gathering daemon


SYNOPSIS
        #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);


DESCRIPTION
       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.


RETURN VALUES
       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.


SEE ALSO
       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>.