Crypt::OpenSSL::Random (3)

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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 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.

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 this function does not exist.

random_status ()

This function returns true if the

PRNG

has sufficient seeding.

BUGS

Because of the internal workings of OpenSSL's random library, the pseudo-random number generator () 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 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

SEE ALSO

perl(1), rand(3), RAND_add(3), RAND_egd(3), RAND_bytes(3).