use Mcrypt;

my $key = 'test-math' . "\0" x 7;       # Must be in blocks of 16, null padded
my $plaintext = "test-math" . "\0" x 23;  # Must be in blocks of 32, null padded

my $td = Mcrypt->new( algorithm => 'rijndael-256', mode => 'ecb' );
$td->init($key, ' 'x32);   # Second parameter is discarded, but warns without
my $encrypted = $td->encrypt($plaintext);
print unpack('H*', $encrypted), $/;
$td->end();