Research On Cryptanalysis And Application Of Authenticated Encryption

Authenticated Encryption has developed rapidly in recent years,showing outstanding security,efficiency,and power consumption advantages.At the same time,new progress has been made in emerging fields such as sensor networks,distributed control systems,the Internet of Things,cyber-physical systems,and smart grids,which require secure,efficient,and lightweight cryptographic algorithms as support.With the emergence of new demands,many newly designed authenticated encryption algorithms have emerged as the times require.A worthy concern is how to propose new cryptanalysis methods based on the unique design of these algorithms and how to use them to solve problems in real-life effectively.This thesis mainly does the following work on the cryptanalysis and application of authenticated encryption:(1)In terms of the cryptanalysis of authenticated encryption: this thesis proposes a method to convert discrete operations into continuous operations to reveal the pattern that the output changes with the input of cryptographic algorithms solving the difficulty caused by the almost random correspondence between the output and input.By applying this method to Xoodoo,the underlying permutation of Xoodyak(a finalist of the NIST lightweight cryptography project),the continuous model of Xoodoo is obtained.Based on this,a genetic algorithm(GA)assisted cryptanalysis method is proposed for the known-plaintext state-recovery attack on round-reduced Xoodyak under the nonce-respecting setting,which describes the goal of cryptanalysis as an objective function optimized with GA.Consequently,the attacker can abstract the potential information of the unknown state of Xoodyak from the results given by GA.Compared with traditional methods,the method is general and can be performed in restricted scenarios.Simultaneously,the method is easy to implement even on complex cryptographic algorithms,as GA can work well with lower complexity,both in time and data complexity.(2)In terms of the application of authenticated encryption: established on the security analysis of authenticated encryption,this thesis proposes a decentralized contact tracing scheme,DP2 CT.The scheme is based on lightweight authenticated encryption,compatible with most resource-constrained devices with Blue Tooth,such as smartwatches,smartbands,and Blue Tooth trackers,enabling more flexible contact tracing.The scheme can serve as a fundamental public health tool to block virus transmission and decrease mortality.The scheme requires few resources while operating efficiently and does not need any personal information of users,which ensures privacy.The scheme does not require a central server’s participation,and users send and receive anonymous identifiers to and from others via Blue Tooth and use this identifier to determine infection risk.This thesis conducts a self-assessment of the security of DP2 CT by studying the safety hazards of the existing contact tracing scheme.The scheme can prevent most attacks,provide better safety protection,have a concise structure,and be easy to implement.The scheme is implemented on an ARM platform to analyze the performance experimentally,and results indicate that DP2 CT has excellent performance as an efficient,secure,and lightweight decentralized contact tracing scheme.