  This work considers the two-way wiretap channel in which two legitimate
users, Alice and Bob, wish to exchange messages securely in the presence of a
passive eavesdropper Eve. In the full-duplex scenario, where each node can
transmit and receive simultaneously, we obtain new achievable secrecy rate
regions based on the idea of allowing the two users to jointly optimize their
channel prefixing distributions and binning codebooks in addition to key
sharing. The new regions are shown to be strictly larger than the known ones
for a wide class of discrete memoryless and Gaussian channels. In the
half-duplex case, where a user can only transmit or receive on any given degree
of freedom, we introduce the idea of randomized scheduling and establish the
significant gain it offers in terms of the achievable secrecy sum-rate. We
further develop an experimental setup based on a IEEE 802.15.4-enabled sensor
boards, and use this testbed to show that one can exploit the two-way nature of
the communication, via appropriately randomizing the transmit power levels and
transmission schedule, to introduce significant ambiguity at a noiseless Eve.
