| =pod |
| |
| =head1 NAME |
| |
| RAND_bytes, RAND_pseudo_bytes - generate random data |
| |
| =head1 SYNOPSIS |
| |
| #include <openssl/rand.h> |
| |
| int RAND_bytes(unsigned char *buf, int num); |
| |
| int RAND_pseudo_bytes(unsigned char *buf, int num); |
| |
| =head1 DESCRIPTION |
| |
| RAND_bytes() puts B<num> cryptographically strong pseudo-random bytes |
| into B<buf>. An error occurs if the PRNG has not been seeded with |
| enough randomness to ensure an unpredictable byte sequence. |
| |
| RAND_pseudo_bytes() puts B<num> pseudo-random bytes into B<buf>. |
| Pseudo-random byte sequences generated by RAND_pseudo_bytes() will be |
| unique if they are of sufficient length, but are not necessarily |
| unpredictable. They can be used for non-cryptographic purposes and for |
| certain purposes in cryptographic protocols, but usually not for key |
| generation etc. |
| |
| The contents of B<buf> is mixed into the entropy pool before retrieving |
| the new pseudo-random bytes unless disabled at compile time (see FAQ). |
| |
| =head1 RETURN VALUES |
| |
| RAND_bytes() returns 1 on success, 0 otherwise. The error code can be |
| obtained by L<ERR_get_error(3)|ERR_get_error(3)>. RAND_pseudo_bytes() returns 1 if the |
| bytes generated are cryptographically strong, 0 otherwise. Both |
| functions return -1 if they are not supported by the current RAND |
| method. |
| |
| =head1 SEE ALSO |
| |
| L<rand(3)|rand(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, |
| L<RAND_add(3)|RAND_add(3)> |
| |
| =head1 HISTORY |
| |
| RAND_bytes() is available in all versions of SSLeay and OpenSSL. It |
| has a return value since OpenSSL 0.9.5. RAND_pseudo_bytes() was added |
| in OpenSSL 0.9.5. |
| |
| =cut |
