Detector-decoy high-dimensional quantum key distribution.

Area of Science:

• Quantum Information Science
• Cryptography
• Quantum Communication

Background:

• High-dimensional quantum key distribution (HD-QKD) offers enhanced security and efficiency.
• Decoy-state protocols are crucial for practical QKD security.
• Existing protocols face challenges in implementation complexity and performance.

Purpose of the Study:

• To propose a novel detector-decoy high-dimensional quantum key distribution (DD-HD-QKD) protocol.
• To enhance security against Gaussian collective attacks with simpler operations.
• To improve performance in both infinite and finite-size regimes.

Main Methods:

• Utilizing a detector-decoy strategy within a high-dimensional QKD framework.
• Employing threshold detectors and a variable attenuator for simplified implementation.
• Conducting numerical evaluations to assess protocol performance.

Main Results:

• The proposed DD-HD-QKD protocol demonstrates superior performance compared to single-decoy protocols and matches two-decoy protocols in the infinite-size regime.
• The protocol achieves better results in the finite-size regime.
• The advantages of the detector-decoy method are more pronounced with lower detector efficiency.

Conclusions:

• The detector-decoy method provides a practical and secure approach for HD-QKD.
• The proposed protocol simplifies implementation while maintaining high security and efficiency.
• This method shows significant promise for future secure communication systems, particularly in scenarios with imperfect detectors.