Experimental vulnerability analysis of QKD based on attack ratings.

Area of Science:

• Quantum Information Science
• Cybersecurity
• Applied Physics

Background:

• Classical cryptographic hardware security evaluation often employs attack ratings.
• Quantum Key Distribution (QKD) security requires robust assessment against practical threats.
• Continuous-variable QKD (CV-QKD) systems are susceptible to various security vulnerabilities.

Purpose of the Study:

• To adapt and apply attack ratings for evaluating the security of QKD systems.
• To experimentally assess the vulnerability of CV-QKD against saturation attacks.
• To identify primary threats to practical CV-QKD implementations.

Main Methods:

• Developed and applied an attack rating methodology inspired by classical cryptography.
• Conducted experimental vulnerability assessments of CV-QKD systems.
• Investigated two distinct detector saturation attack strategies: coherent displacement and external laser illumination.

Main Results:

• A detector saturation attack via large coherent displacement resulted in a high attack rating, indicating experimental difficulty.
• A novel, simpler attack strategy using an external laser to saturate detectors yielded a low attack rating.
• The low rating for the laser-based attack highlights it as a primary threat to practical CV-QKD systems.

Conclusions:

• Attack ratings provide a valuable framework for quantifying QKD system vulnerabilities.
• The external laser saturation attack represents a significant and practical security concern for CV-QKD.
• Integrating attack ratings into QKD design and engineering enhances system security standards.