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NAME
Crypt::OpenSSL::Random - OpenSSL/LibreSSL pseudo-random number generator
access
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);
DESCRIPTION
"Crypt::OpenSSL::Random" provides the ability to seed and query the
OpenSSL and LibreSSL library's pseudo-random number generators.
Note: On LibreSSL random_egd() is not defined.
EXPORT
None by default.
Static Methods
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.
random_pseudo_bytes (IV num_bytes)
This function, is similar to "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.
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!
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 -1 if not enough bytes were read, or if the
connection to the daemon failed.
"libressl" considers this function insecure, so with libressl or an
openssl with no-egd this function does not exist.
random_status ()
This function returns 1 if the PRNG has sufficient seeding. or 0 if
not.
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
"random_egd", in one place.
AUTHOR
Ian Robertson, "iroberts@cpan.com"
Now maintained by Reini Urban, "rurban@cpan.org"
LICENSE
This module is available under the same licences as perl, the Artistic
license and the GPL.
SEE ALSO
perl(1), rand(3), RAND_add(3), RAND_egd(3), RAND_bytes(3).
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