Real-Time Cryptographic Agility for Autonomous UAV Swarms: A Performance-Driven Approach to Post-Quantum Migration

Autonomous UAV swarms are increasingly deployed for time-sensitive missions where secure communication and strict real-time control must coexist. The transition to post-quantum cryptography (PQC) introduces substantial computational overhead that can push cryptographic operations beyond coordination deadlines if algorithms are fixed a priori. This challenge is compounded by dynamic operational requirements: reconnaissance missions prioritize efficiency while tactical operations demand higher security, which static cryptographic configurations cannot accommodate. We evaluate cryptographic agility, defined as adapting algorithms to operational context, using a simulator grounded in empirical cycle counts for ARM Cortex-M4 processors. Through extensive simulation, agile configurations maintain high deadline compliance rates while static policies experience significant degradation under operational stress. Because no single NIST-approved PQC scheme jointly optimizes security, latency, and energy across varying mission requirements, these results provide evidence that adaptive selection is necessary to address performance bottlenecks in post-quantum UAV swarms. We also discuss design implications and outline how agility can be integrated with real-time coordination and provisioning workflows.