1=pod 2 3=head1 NAME 4 5RAND_bytes, RAND_pseudo_bytes - generate random data 6 7=head1 SYNOPSIS 8 9 #include <openssl/rand.h> 10 11 int RAND_bytes(unsigned char *buf, int num); 12 13 int RAND_pseudo_bytes(unsigned char *buf, int num); 14 15=head1 DESCRIPTION 16 17RAND_bytes() puts B<num> cryptographically strong pseudo-random bytes 18into B<buf>. An error occurs if the PRNG has not been seeded with 19enough randomness to ensure an unpredictable byte sequence. 20 21RAND_pseudo_bytes() puts B<num> pseudo-random bytes into B<buf>. 22Pseudo-random byte sequences generated by RAND_pseudo_bytes() will be 23unique if they are of sufficient length, but are not necessarily 24unpredictable. They can be used for non-cryptographic purposes and for 25certain purposes in cryptographic protocols, but usually not for key 26generation etc. 27 28The contents of B<buf> is mixed into the entropy pool before retrieving 29the new pseudo-random bytes unless disabled at compile time (see FAQ). 30 31=head1 RETURN VALUES 32 33RAND_bytes() returns 1 on success, 0 otherwise. The error code can be 34obtained by L<ERR_get_error(3)|ERR_get_error(3)>. RAND_pseudo_bytes() returns 1 if the 35bytes generated are cryptographically strong, 0 otherwise. Both 36functions return -1 if they are not supported by the current RAND 37method. 38 39=head1 SEE ALSO 40 41L<rand(3)|rand(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, 42L<RAND_add(3)|RAND_add(3)> 43 44=head1 HISTORY 45 46RAND_bytes() is available in all versions of SSLeay and OpenSSL. It 47has a return value since OpenSSL 0.9.5. RAND_pseudo_bytes() was added 48in OpenSSL 0.9.5. 49 50=cut 51