Quantum key distribution with delayed privacy amplification and its application to the security proof of a two-way deterministic protocol

Chi-Hang Fred Fung, Xiongfeng Ma, H. F. Chau, Qing-yu Cai
2012 Physical Review A. Atomic, Molecular, and Optical Physics  
Privacy amplification (PA) is an essential post-processing step in quantum key distribution (QKD) for removing any information an eavesdropper may have on the final secret key. In this paper, we consider delaying PA of the final key after its use in one-time pad encryption and prove its security. We prove that the security and the key generation rate are not affected by delaying PA. Delaying PA has two applications: it serves as a tool for significantly simplifying the security proof of QKD
more » ... ty proof of QKD with a two-way quantum channel, and also it is useful in QKD networks with trusted relays. To illustrate the power of the delayed PA idea, we use it to prove the security of a qubit-based two-way deterministic QKD protocol which uses four states and four encoding operations.
doi:10.1103/physreva.85.032308 fatcat:dqgfgatjqbhglhags6blh5ijdm