Security of the traditional quantum key distribution protocols with finite-key lengths

Quantum key distribution(QKD)in principle can provide unconditional secure communication between distant parts.However,when finite-key length is taken into account,the security can only be ensured within certain security level.In this paper,we adopt the Chernoff bound analysis method to deal with finite-key-size effects,carrying out corresponding investigations on the relationship between the key generation rate and security parameters for different protocols,including BB84,measurement-device-independent and twin-field QKD protocols.Simulation results show that there exists a fundamental limit between the key rate and the security parameters.Therefore,this study can provide valuable references for practical application of QKD,getting a nice balance between the key generation rate and the security level.