Dialog codes for secure wireless communications

We investigate the feasibility of achieving perfect secrecy in wireless network communications without shared secrets. We introduce a secure coding problem in which not only the sender but also the receiver participates in the coding. In essence, the receiver's role is to selectively jam the sender's transmission at the level of bits, bytes, or packets. We then design a class of secure codes, which we call dialog codes, for diverse channel models and receiver models. Our codes are simple and efficient, with only O(1) complexity in both the encoding and the decoding process, and achieve optimal coding rate in some channel models. This, along with their potential for augmenting security and/or simplifying security bootstrapping, makes them worthy of consideration for resource-constrained wireless sensor network devices. By way of experimental validation, we study the channel jamming characteristics of extant mote radios - specifically, CC2420 (IEEE 802.15.4) and CC1000 - in experiments, observe their time-varying channel behavior, and demonstrate the correctness and robustness of implementations of our dialog codes at the byte-level and at the packet-level in the presence of dynamic channel fluctuations.