View file File name : Random.pm Content :package Crypt::OpenSSL::Random; use strict; use vars qw($VERSION @ISA @EXPORT @EXPORT_OK); use XSLoader; require Exporter; @ISA = qw(Exporter); @EXPORT_OK = qw( random_bytes random_pseudo_bytes random_seed random_egd random_status ); $VERSION = '0.15'; XSLoader::load( __PACKAGE__, $VERSION ); 1; __END__ =head1 NAME Crypt::OpenSSL::Random - OpenSSL/LibreSSL pseudo-random number generator access =head1 SYNOPSIS use Crypt::OpenSSL::Random; Crypt::OpenSSL::Random::random_seed($good_random_data); Crypt::OpenSSL::Random::random_egd("/tmp/entropy"); Crypt::OpenSSL::Random::random_status() or die "Unable to sufficiently seed the random number generator". my $ten_good_random_bytes = Crypt::OpenSSL::Random::random_bytes(10); my $ten_ok_random_bytes = Crypt::OpenSSL::Random::random_pseudo_bytes(10); =head1 DESCRIPTION C<Crypt::OpenSSL::Random> provides the ability to seed and query the B<OpenSSL> and B<LibreSSL> library's pseudo-random number generators. Note: On B<LibreSSL> C<random_egd()> is not defined. =head2 EXPORT None by default. =head1 Static Methods =over =item random_bytes (IV num_bytes) This function, returns a specified number of cryptographically strong pseudo-random bytes from the PRNG. If the PRNG has not been seeded with enough randomness to ensure an unpredictable byte sequence, then a false value is returned. =item random_pseudo_bytes (IV num_bytes) This function, is similar to C<random_bytes>, but the resulting sequence of bytes 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. =item random_seed (PV random_bytes_string) This function seeds the PRNG with a supplied string of bytes. It returns true if the PRNG has sufficient seeding. Note: calling this function with non-random bytes is of limited value at best! =item random_egd (PV egd_string) This function seeds the PRNG with data from the specified entropy gathering daemon. Returns the number of bytes read from the daemon on success, or C<-1> if not enough bytes were read, or if the connection to the daemon failed. C<libressl> considers this function insecure, so with libressl this function does not exist. =item random_status () This function returns true if the PRNG has sufficient seeding. =back =head1 BUGS Because of the internal workings of OpenSSL's random library, the pseudo-random number generator (PRNG) accessed by Crypt::OpenSSL::Random will be different than the one accessed by any other perl module. Hence, to use a module such as Crypt::OpenSSL::Random, you will need to seed the PRNG used there from one used here. This class is still advantageous, however, as it centralizes other methods, such as C<random_egd>, in one place. =head1 AUTHOR Ian Robertson, C<iroberts@cpan.com> Now maintained by Reini Urban, C<rurban@cpan.org> =head1 LICENSE This module is available under the same licences as perl, the Artistic license and the GPL. =head1 SEE ALSO perl(1), rand(3), RAND_add(3), RAND_egd(3), RAND_bytes(3). =cut