  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.
