ssh or equivalent on lispm/macivory

I've got a MacIvory 2 and a couple of 3640s.  Having them networked
together is fairly straight-forward.  Unfortunately, if I want that
network to be connected to anything other than Lisp machines living
within my house, they can only use encrypted means for user data
communication.  I.e., DNS and such can still be in the clear, but
remote logins, X sessions, file transfers, etc, have to be encrypted.
The existing infrastructure is very much geared to ssh, but that's not
a strict requirement.

What I'd like is to have an ssh client and server for all three of the
Lisp machines, integrated such that commands like ``Copy File src dst''
will use the encrypted service rather than trying to use NFS, FTP, or
whatever; this includes file access via LMFS between the Lisp machines
themselves.  Ssh is an example, Kerberos with decent encryption is an
option, as is just about any other strong authentication+encryption
system that can be made to work on miscellaneous Unix boxes and the
Lisp machines is a viable candidate.

A google search was less than completely helpful, but this *is*
getting a little esoteric, and not everyone is necessarily motivated
to jump on the latest-fad bandwagon like web pages and such.  So, has
anyone here done anything along the lines of the above, or know of
someone else who has, and is willing to share?  If not, I have this
funny feeling Rainer's going to get really tired of me asking
questions about where to hook into the low-level data-transfer
routines.  On the other hand, I've never really had to do bit-
twiddling in Lisp before, so it's an area of knowledge to explore....

Thanks.

	Dworkin