Mounting a "Secure" filesystem in UNIX

[Sameer <sameer@uclink.berkeley.edu>]

	Right now I'm running Linux with SLIP at home, and with
telnetd disabled, I feel very secure keeping my PGP secret key on the
system. The drawback inherent in this system, however, of course, is
that I can't connect to my home system and collect mail/do work/etc.
remotely.
	(That's why I have all mail going to uclink, from which point
it goes both to my home machine and netcom.)

	I was wondering if it was possible to mount a "secure"
filesystem/partition using Linux or some other free version of UNIX,
so that it's inaccessible if logged in remotely, but accessibly when
logged in locally.
	That way I can store my PGP secret key on the "secure"
filesystem, and keep telnetd enabled.

	Any thoughts?

Thanks,
	Sameer