SUDOKU: Secure and usable deployment of keys on wireless sensors

Initial deployment of secrets plays a crucial role in any security design, but especially in hardware constrained wireless sensor networks. Many key management schemes assume either manually pre-installed shared secrets or keys authenticated with the aid of out-of-band channels. While manually installing secret keys affects the practicability of the key deployment, out-of-band channels require additional interfaces of already hardware-limited wireless sensor nodes. In this work, we present a key deployment protocol that uses pair-wise ephemeral keys generated from physical layer information which subsequently enables an authenticated exchange of public keys. Hence, this work presents an elegant solution to the key deployment problem without requiring more capabilities than already available on common low-cost devices. To justify the feasibility of this solution, we implement and experimentally evaluate the proposed key deployment protocol using commodity wireless sensor motes.