Multi-channel Security Protocols

Ford Long Wong ( Cambridge University Computer Laboratory )

We examine ad-hoc pairing security protocols that strengthen key exchanges over an insecure channel such as radio, with additional transmissions over other channels having other security properties though more limited bandwidth. Different types of channels have existed for a long time in fact, and a variety of such auxiliary channels are especially prevalent in a ubicomp environment. Making the options explicit allow us to model the adversary behaviour better, and to make further advances in security protocol design. We offer several of our own protocol proposals, and highlight some findings such as achieving security with a unidirectional low-bandwidth channels, the usage of one-bit-payload per message channels, as well as usability and complexity concerns.