  We consider two-way wire-tap channels, where two users are communicating with
each other in the presence of an eavesdropper, who has access to the
communications through a multiple-access channel. We find achievable rates for
two different scenarios, the Gaussian two-way wire-tap channel, (GTW-WT), and
the binary additive two-way wire-tap channel, (BATW-WT). It is shown that the
two-way channels inherently provide a unique advantage for wire-tapped
scenarios, as the users know their own transmitted signals and in effect help
encrypt the other user's messages, similar to a one-time pad. We compare the
achievable rates to that of the Gaussian multiple-access wire-tap channel
(GMAC-WT) to illustrate this advantage.
