(Blowfish_PP)... good catch! Really, though... good encryption, real encryption, is easy to do even with only a small amount of RAM. One thing not to be overlooked is that quite a few operating-systems ship with encryption-libraries for other purposes, and there are available Perl bindings to them. If you know that your app is being deployed to, say, Windows-32 of any recent vintage, then you also know that this system has its own built-in cipher stack. So it's "not in your own code," and it's "already there." Sure, it's Win32-specific (say), but who cares?