Entropy of the Quantum-Classical Interface: A Potential Metric for Security

The quantum-classical interface (QCI) i.e., the boundary where quantum and classical systems interact, introduces unique security challenges and potential vulnerabilities within quantum technologies. This position paper explores the use of entropy as one metric to monitor and secure information transfer across the QCI. We propose an initial QCI security framework, outlining criteria by which entropy-based measures contribute to detecting deviations and potential threats to quantum system integrity. By presenting these theoretical constructs, we aim to catalyze further investigation and discussion, establishing a basis for empirical validations and future development of practical quantum security strategies.