# Finite-Key Analysis of 1-Decoy Method Quantum Key Distribution with Intensity Fluctuation  
[PERSON]  
1 Henan Key Laboratory of Quantum Information and Cryptography, SSF IEU, Zhengzhou 450001, China; [EMAIL_ADDRESS] (C.Z. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (Y.W. ); [EMAIL_ADDRESS] (Y.L. ); [EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (X.Z.) [PERSON]  
1 Henan Key Laboratory of Quantum Information and Cryptography, SSF IEU, Zhengzhou 450001, China; [EMAIL_ADDRESS] (C.Z. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (Y.W. ); [EMAIL_ADDRESS] (Y.L. ); [EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (X.Z.) [PERSON]  
1 Henan Key Laboratory of Quantum Information and Cryptography, SSF IEU, Zhengzhou 450001, China; [EMAIL_ADDRESS] (C.Z. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (Y.W. ); [EMAIL_ADDRESS] (Y.L. ); [EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (X.Z.) [PERSON]  
1 Henan Key Laboratory of Quantum Information and Cryptography, SSF IEU, Zhengzhou 450001, China; [EMAIL_ADDRESS] (C.Z. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (Y.W. ); [EMAIL_ADDRESS] (Y.L. ); [EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (X.Z.) [PERSON]  
1 Henan Key Laboratory of Quantum Information and Cryptography, SSF IEU, Zhengzhou 450001, China; [EMAIL_ADDRESS] (C.Z. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (Y.W. ); [EMAIL_ADDRESS] (Y.L. ); [EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (X.Z.) [PERSON]  
1 Henan Key Laboratory of Quantum Information and Cryptography, SSF IEU, Zhengzhou 450001, China; [EMAIL_ADDRESS] (C.Z. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (Y.W. ); [EMAIL_ADDRESS] (Y.L. ); [EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (X.Z.) [PERSON]  
1 Henan Key Laboratory of Quantum Information and Cryptography, SSF IEU, Zhengzhou 450001, China; [EMAIL_ADDRESS] (C.Z. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (Y.W. ); [EMAIL_ADDRESS] (Y.L. ); jms@qiclab. block size, the results [21] indicate the 1-decoy state method is more advantageous than the 2-decoy state method by conducting a rigorous finite-key analysis using Hoeffding's inequality [22]. Many efforts have been made to improve the finite-key security bound by considering the statistical characteristics such as the Hoeffding's inequality, the Chernoff bound [23] and the Improved-Chernoff bound [24], which assume that the former event, current event and later event are independently related. However, in real-life QKD setups, since the intensities of the emitting signals from the photon source are not always steady, the counting events before and later gathered in the measurement setups may be related to each other [25]. Thus, the previous finite-key analysis methods are not suitable for these event-dependent scenarios. Then, it is necessary to find an appropriate statistical model to handle the dependent events and renew the upper security bound by taking intensity fluctuations into consideration. Otherwise, the eavesdropper ([PERSON]) can acquire more secret information if one does not refresh the security bound. For different protocols, much work [26; 27; 28] has been acquired to relax the assumption that [PERSON] can control the intensities of light sources with great accuracy. In particular, [PERSON] et al. [18] studied the effects of both intensity fluctuations and classical statistical fluctuations for the 2-decoy state method with dependent events. In this paper, we turn to the 1-decoy state method and re-examine its finite-key bound by taking both intensity fluctuations and dependent events into account. We obtain a secret key rate of the 1-decoy state method with different data sizes and different intensity fluctuations. Numerical simulations indicate that, as with the 2-decoy state method, intensity fluctuations have non-negligible effects on the performance of the 1-decoy state method.