Quantum key distribution with hacking countermeasures and long term field trial.

Area of Science:

• Quantum Information Science
• Cybersecurity
• Applied Physics

Background:

• Quantum key distribution (QKD) promises information-theoretic security, but practical implementations face vulnerabilities.
• Side-channel attacks exploit discrepancies between theoretical models and physical QKD device behavior.
• Demonstrating security in both theoretical and physical domains is crucial for QKD adoption.

Purpose of the Study:

• To develop and evaluate a QKD system resilient to various hacking attacks.
• To validate the system's security against both theoretical and practical implementation flaws.
• To assess the QKD system's performance and security in a live metropolitan network.

Main Methods:

• Designed a QKD system incorporating security features against Trojan horse, detector blinding, phase randomization, and photon number splitting attacks.
• Deployed the QKD system in a 45 km metropolitan telecom network link.
• Monitored system operation and secure key distribution over a 2.5-month period.
• Analyzed security against coherent attacks, a broader class than typically considered.

Main Results:

• The QKD system operated continuously for 2.5 months, distributing 1.33 Tbits of secure key data.
• A stable secure key rate exceeding 200 kbit/s was maintained.
• The system demonstrated resilience against multiple hacking attack vectors.
• Security was validated against advanced coherent attacks.

Conclusions:

• The developed QKD system offers enhanced resilience against practical implementation vulnerabilities and hacking attempts.
• Real-world deployment confirms the system's capability for continuous, high-rate secure key distribution.
• The findings support the practical viability of information-theoretically secure communication networks.