Zheng-Fu Han

Recent studies have revealed critical source-side vulnerabilities in practical quantum key distribution systems. Despite their demonstrated risks, these threats receive limited attention in both academic discussions and practical implementations. To highlight the urgency of addressing source-side vulnerabilities, we will report two widespread but overlooked loopholes: the induced-photorefractive effect and the pattern effect, including a report of the first-time system-level attack against a running MDI-QKD. Except for the attack, we will also report countermeasures against the loopholes, including a fully-passive QKD architecture resistant to encoding side-channels and a correlation-immune QKD protocol mitigating the pattern effect. These works provide essential insights and solutions for advancing the practical deployment of secure QKD systems.