Biological Time Constants as Anti-Replay Mechanisms\\ for Distributed Timekeeping

Distributed systems increasingly rely on external timing references whose signals can be observed, replayed, or synthetically generated by an adversary. While existing defenses focus on statistical fusion, anomaly detection, and reference diversity, most timing inputs remain fundamentally memoryless, reflecting only instantaneous state rather than temporal history. This paper introduces biological and chemical processes as a new class of timing references characterized by intrinsic time constants and hysteresis. Such processes integrate environmental conditions over extended intervals and cannot be retroactively forged without reproducing the underlying physical or biological evolution. We argue that biological time constants provide a form of temporal anti-replay defense, complementing electronic and network-based timing sources. We formalize this concept, analyze relevant biological and chemical mechanisms, and propose an architecture for integrating hysteretic references into multi-reference timekeeping systems.