I want this: on sending, ask me for my PGP passphrase for signing, but
don't sign the message if I pressed enter without entering the
passphrase.  How can I do this?  Do I need some lisp programming?

Thank you.

-- 
Carl Lei (XeCycle)
Department of Physics, Shanghai Jiao Tong University
OpenPGP public key: 7795E591
Fingerprint: 1FB6 7F1F D45D F681 C845 27F7 8D71 8EC4 7795 E591