As quantum computing and AI introduce a new era of cyber risk, federal agencies must prepare for the disruptive impact these technologies will have on mission security. This dispatch from DAFITC 2026 explores how organizations can future-proof their security posture by transitioning to post-quantum cryptography, defending against adversarial AI techniques such as data poisoning and model evasion, and applying Zero Trust and secure-by-design principles to protect AI-driven systems, sensitive data, and mission operations.