=pod =head1 NAME RAND_egd, RAND_egd_bytes, RAND_query_egd_bytes - query entropy gathering daemon =head1 SYNOPSIS #include 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); =head1 DESCRIPTION On older platforms without a good source of randomness such as C, 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 L or L. RAND_egd_bytes() requests B bytes of randomness from an EGD at the specified socket B, and passes the data it receives into RAND_add(). RAND_egd() is equivalent to RAND_egd_bytes() with B set to 255. RAND_query_egd_bytes() requests B bytes of randomness from an EGD at the specified socket B, where B must be less than 256. If B is B, it is equivalent to RAND_egd_bytes(). If B is not B, 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. =head1 RETURN VALUE 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. =head1 SEE ALSO L, L =head1 COPYRIGHT Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved. 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 L. =cut