SPoTKD: A Protocol for Symmetric Key Distribution over Public Channels Using Self-Powered Timekeeping Devices

In this paper, we present novel secret key distribution protocols using low-cost, hardware chipsets containing millions of synchronized self-powered timers. The secret keys are derived based on the timers' physical dynamic responses which provide security against any potential side-channel attacks, malicious tampering, or snooping. Using the behavioral model of the self-powered timers, we first show that the key-strings derived from the timers can pass the randomness test as defined by the National Institute of Standards and Technology (NIST) suite. The key-strings are then used in two key exchange protocols which exploit elapsed time as one-way functions. The protocols proposed in this paper facilitate secure communication between (a) a user and a remote Server; and (b) two users. Using Monte-Carlo simulations, we investigate the scalability and the security of these protocols against different adversarial attacks. We also investigate the robustness of these protocols in the presence of real-world operating conditions and we investigate the use of error-correcting codes to mitigate noise-related artifacts.