Security analysis of practical continuous-variable quantum key distribution systems under laser seeding attack.

Area of Science:

• Quantum Information Science
• Cybersecurity
• Optical Communications

Background:

• Practical continuous-variable quantum key distribution (CV-QKD) systems, including one-way and measurement-device-independent (MDI-QKD), are susceptible to sophisticated attacks.
• Laser seeding attacks can manipulate the intensity of optical signals in CV-QKD systems, posing a significant security threat.

Purpose of the Study:

• To investigate the security vulnerabilities of practical one-way CV-QKD and CV-MDI-QKD systems when subjected to laser seeding attacks.
• To demonstrate how laser seeding attacks can lead to an overestimation of secret key rates, creating security loopholes.
• To propose and validate a real-time monitoring scheme to mitigate these vulnerabilities.

Main Methods:

• Simulating laser seeding attacks by injecting light into the laser diodes of CV-QKD systems.
• Analyzing parameter estimation under attack conditions to assess secret key rate accuracy.
• Developing and evaluating a real-time monitoring scheme for precise secret key rate evaluation.

Main Results:

• Laser seeding attacks were shown to increase optical signal intensity, leading to overestimated secret key rates in practical CV-QKD and CV-MDI-QKD.
• This overestimation creates a security loophole, allowing adversaries to gain information about the secret key.
• The proposed real-time monitoring scheme effectively identified and countered the effects of the laser seeding attack.

Conclusions:

• Practical CV-QKD and CV-MDI-QKD systems are vulnerable to laser seeding attacks, compromising their security.
• A real-time monitoring scheme is crucial for accurately evaluating secret key rates and ensuring the security of CV-QKD systems.
• The proposed monitoring scheme provides an effective defense against laser seeding attacks, enhancing the trustworthiness of quantum key distribution.