|A Two-way QKD Protocol Outperforming One-way Protocols at Low QBER
|Jari Veli Elias Lietzén, Roope Iikanpoika Vehkalahti, Olav Tirkkonen, Aalto University, Finland
|P.11: Topics in Privacy and Cryptography
|Cryptography, Security and Privacy
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|Two-way quantum key distribution (QKD) protocols can provide positive secret key rates for considerably higher quantum bit error rates (QBER) than one-way protocols. However, when QBER is low, only modest key rate gains have been achieved. This is one of the major obstacles for using two-way protocols. In this paper we introduce a new two-way QKD protocol which is a step towards overcoming this shortcoming. Under the assumption that the eavesdropper can only perform individual symmetric quantum attacks, our protocol performs quantum key distribution with a secret key rate that is higher than the information theoretical bound limiting the performance of any one-way protocol. This holds true also for very low QBER values.