Quantum Key Recycling with Optimal Key Recycling Rate based on Error Rate

Abstract

This thesis proposes a new Quantum Key Recycling (QKR) protocol which recycles used keys according to the error rate The proposed QKR protocol can tolerate the noise in the quantum channel The earlier studies [1-4] also proposed QKR protocols with noise tolerance Unfortunately there is a common security loophole in these protocols The proposed QKR protocol is designed to avoid this security loophole and the key recycling rate of the pre-shared keys is optimized depending on the noise level The security proof shows the security of the recycled keys is universal composable This thesis also answers the question that is there any benefit for the QKR protocols to distribute keys as compared to the Quantum Key Distribution (QKD) protocols? The key sharing rate which is the other version of the key rate is defined to compare the efficiency of the proposed QKR protocol with that of QKD protocols The key sharing rate can be calculated for both the QKD protocols and the QKR protocols and the key sharing rate of the proposed QKR is then calculated According to the comparison of the key sharing rate this thesis finds that if using the proposed QKR protocol to distribute keys it is more efficient than BB84 in some situations

Date of Award	2020
Original language	English
Supervisor	Tzone-Lih Hwang (Supervisor)