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