Performance Characterization of Quantum-Safe Break-Glass Access for Electronic Medical Records

Abstract

Migrating electronic medical records (EMRs) to post-quantum cryptography is urgent, because records exfiltrated today can be decrypted once a cryptographically relevant quantum computer exists. EMRs add a requirement generic data protection lack: regulated break-glass access, in which an unauthorized clinician opens a record during an emergency under mandatory accountability. PQ-BG is a break-glass EMR scheme built entirely from quantum-resistant components, AES-256-GCM, ML-KEM-768 (FIPS 203), Shamir (t, n) secret sharing, and an ML-DSA-65-signed (FIPS 204) hash-chained audit trail. A design alone, however, does not establish whether quantum-safe accountable emergency access is practical, or what it costs. This paper reports a seven-part empirical characterization on commodity clinical-workstation hardware. Record protection stays under 150 ms even for 200 MB DICOM studies; fully audited emergency access completes in 259 ms at a (3, 5) custodian configuration; per-record overhead is a constant 9.2 KB; and a single workstation sustains roughly 23 protections per second with linear scaling to 10,000 records. A classical RSA/ECDH baseline isolates migration cost. The decomposition shows that accountability signatures, not lattice key encapsulation, dominate emergency-path latency, redirecting where optimization belongs. All figures are conservative upper bounds from a Pure-Python backend.