Performance evaluation of twin-field quantum key distribution with injection-type attacks

Area of Science:

• Quantum Information Science
• Cryptography
• Optical Communication Systems

Background:

• Twin-field quantum key distribution (TF-QKD) surpasses repeaterless QKD limits for secure long-distance communication.
• Practical TF-QKD security is vulnerable to imperfect intensity modulation from source imperfections and attacks.

Purpose of the Study:

• Investigate the security of the NPP TF-QKD protocol under imperfect intensity modulation.
• Analyze vulnerabilities to Trojan-horse and photorefractive attacks.
• Provide a finite-key security proof considering source-side information leakage.

Main Methods:

• Utilized the reference technique for security proof.
• Incorporated source-side information leakage into the analysis.
• Performed numerical simulations with realistic parameters.

Main Results:

• NPP TF-QKD surpasses the rate-loss bound with realistic transmitter isolation.
• Achieved secret-key rates close to ideal performance.
• Demonstrated strong robustness against modulation deviations from photorefractive effects.

Conclusions:

• TF-QKD maintains practical security despite realistic source imperfections.
• Results offer quantitative guidance for designing secure quantum communication systems.
• Confirms TF-QKD's viability for secure, long-distance communication.