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Journal Article
Countermeasure for Security Loophole Caused by Asymmetric Correlations of Reference Frame Independent Quantum Key Distribution with Fewer Quantum States
- Authors
- Kyongchun Lim, Byung-Seok Choi, Ju Hee Baek, Minchul Kim, Joong-Seon Choe, Kap-Joong Kim, Young-Ho Ko, Chun Ju Youn
- Issue Date
- 2021-06
- Citation
- Optics Express, v.29, no.12, pp.18966-18975
- ISSN
- 1094-4087
- Publisher
- Optical Society of America (OSA)
- Language
- English
- Type
- Journal Article
- Abstract
- One of the challenging issues in free-space quantum key distribution (QKD) is the requirement of active compensation of the reference frame between the transmitter and receiver. Reference frame independent (RFI) QKD removes active compensation, but it requires more quantum states. A recent proposal can effectively reduce the required quantum states, but this can be achieved assuming the correlations defined in RFI QKD are symmetric. In a real QKD system, such symmetric correlations cannot always be satisfied owing to the device imperfections and optical misalignment. We theoretically analyze the effect of asymmetric correlations. Consequently, we report that the asymmetry causes security loopholes and provide a countermeasure to prevent them. Furthermore, we provide the experimental results of a free-space RFI QKD system to verify the countermeasure for the aforementioned problem. In conclusion, our work provides feasibility of the practical RFI QKD system with fewer quantum states by effectively preventing the security loophole.
- KSP Keywords
- Active compensation, Challenging issues, Free Space, Optical misalignment, Quantum states, Reference frame, Transmitter and receiver, quantum key distribution