Weak randomness impacts the security of reference-frame-independent quantum key distribution

Area of Science:

• Quantum Information Science
• Quantum Cryptography
• Quantum Communication Security

Background:

• Perfect randomness is crucial for secure quantum key distribution (QKD) protocols.
• Real-world implementations of RFI-QKD may involve imperfect random number generators or state preparation devices, leading to weak randomness.
• The security implications of such imperfections require thorough investigation.

Purpose of the Study:

• To investigate the impact of weak randomness on state preparation in reference-frame-independent quantum key distribution (RFI-QKD).
• To evaluate the maximal information an eavesdropper can acquire under conditions of weak randomness.
• To assess the effect of weak randomness on reference-frame-independent measurement-device-independent quantum key distribution (RFI-MDI-QKD).

Main Methods:

• Theoretical analysis of information leakage in RFI-QKD systems with imperfect randomness.
• Evaluation of security bounds considering practical experimental parameters.
• Simulation of weak randomness effects on RFI-MDI-QKD performance.

Main Results:

• Even a small proportion of weak randomness significantly impacts the security of RFI-QKD.
• The maximal information an eavesdropper can acquire increases substantially with weak randomness.
• Weak randomness critically damages the performance of RFI-MDI-QKD more than RFI-QKD.

Conclusions:

• The presence of weak randomness poses a serious security threat to RFI-QKD systems.
• Robust random number generation is essential for maintaining the security of QKD protocols.
• RFI-MDI-QKD systems are particularly vulnerable to the detrimental effects of weak randomness.