So, what cant you do? Encrypt the file? Crypt::OpenPGP

my $ciphertext = $pgp->encrypt(
                 Filename   => $file,
                 Recipients => $key_id,
                 Armour     => 1,
           );
[download]

or send an email attachment Mail::Sender

 use Mail::Sender;
 $sender = new Mail::Sender
  {smtp => 'mail.yourdomain.com', from => 'your@address.com'};
 $sender->MailFile({to => 'some@address.com',
  subject => 'Here is the file',
  msg => "I'm sending you the list you wanted.",
  file => 'filename.txt'});
[download]

I got this information in about 5 mins from doing a search on CPAN.