F2 hash?

[anonymous-remailer at shell.portal.com]

Does anyone have a descriptoin of the F2 hash?
F2 is a secret hash from SecurityDynamics, and is used in
their client software.  (Its not the hash in the cards, but
if anyone has a copy of that, it might be fun.)

I'd be very interested in seeing source code in the public
domain to try out a few hacks...

Anyone?  Anyone?  Bueller?

Bueller?