use Crypt::OpenPGP;

my $pgp = Crypt::OpenPGP->new(
  SecRing => "private.keyring",
  PubRing => "public.key"
);

my $data = "Please sign me... PLZ";

my $signature = $pgp->sign(
  Data       => $data,
  KeyID      => "775B1EE7CB2F10CD",
  Passphrase => "XXXXXXXX",
  Detach     => 1,
  Clearsign  => 1
) or die "Could not sign. Got error: $pgp->errstr";

print $signature;