use Crypt::RSA;

my $rsa = new Crypt::RSA;

my ($public, $private) = 
$rsa->keygen ( 
    Identity  => 'Lord Macbeth <macbeth@glamis.com>',
    Size      => 1024,  
    Password  => 'A day so foul & fair', 
    Verbosity => 1,
    KF => 'SSH',
    Filename => 'mykey'
) or die $rsa->errstr();