Cumulative-Exposure Thresholds in Post-Quantum Migration Risk: An Occupation-Time Model with Exact Passage Laws
A Markov model that allows a vulnerable cryptographic deployment to return to a safe state can inadvertently erase risk accumulated before remediation. We formulate a cumulative-exposure threshold model for post-quantum migration analysis. A two-state continuous-time chain alternates between protected and exposed operation, but a separate, nondecreasing occ…

