In this talk we consider secret communication between two special    nodes (``source'' and ``destination'') in a wireless network with    authenticated relays: the message communicated to the destination is to be kept information-theoretically secret from any    eavesdropper within a class.  We develop cooperative schemes which utilize signal interactions in wireless communication over networks with arbitrary topology, and give provable unconditional secrecy guarantees. We analyze many strategies including end-to-end encoding and jamming strategies for inducing secrecy.