Research On Lattice-Based Encryption Algorithm In New Computing Environment

With the rapid development of information technology,several new computing environments have emerged for the increasing new application,such as cloud computing,edge computing,and Internet of Energy(Io E).Cloud computing provides computing and storage services of low-cost,high-efficiency,and high-quality,and edge computing,as an extension of cloud computing,satisfies real-time and intelligent demands from applications.Now new computing environments are gradually used in many fields such as education,medical,and finance.However,the widespread application of new computing environments has also caused new problems and challenges,especially data security and privacy-preserving issues.Therefore,how to ensure the security and privacy of users' data and avoid the leakage of sensitive information has become an important problem to be solved.Cryptographic mechanism is an effective tool to solve the above mentioned security problems,and thus it has received extensive attention from academia to industry.However,with the thriving of quantum science,the emergence of quantum computers will have a subversive impact on the existing cryptography system.Therefore,the design of new cryptographic systems to resist quantum attacks has been widely concerned by the government and researchers.As a good candidate for post-quantum cryptosystem,lattice-based cryptosystem has become a research hotspot in the field of cryptography.To address the problems of resisting quantum computing attacks and practicability faced by existing schemes,this thesis proposes two kinds of post-quantum cryptographic mechanisms,called lattice-based searchable encryption and lattice-based access control encryption,for the requirements of secure search and access control in new computing environments.This dissertation is promised to solve the security problems and application bottlenecks in the new computing environment,as well as promoting the theoretical development and practical application of post-quantum cryptography.The main works of this thesis are as follows:1)This thesis proposes a public key encryption with conjunctive keyword search based on lattice for cloud computing.To address the problems of weak security and retrieval single mode of most existing searchable encryption schemes,this thesis proposes a new cryptographic primitive,named lattice-based conjunctive keyword searchable encryption,for meeting the requirements of data security in the cloud computing environment.The proposed scheme can not only resist quantum computing attacks,but also support the conjunctive keyword search model.Specifically,according to the proposed system model and security model,this thesis first constructs two concrete instantiation schemes for single-user and multi-user scenarios based on the LWE security assumption,respectively.This thesis then provides formal proof to analyze the security of proposed schemes under the random oracle model.Finally,this thesis compares our schemes with other related works in terms of computational and communication complexity,and the results demonstrate the practicability of them.2)This thesis proposes an access control encryption without sanitizer based on lattice for Internet of Energy.To solve the problem of relying on trusted sanitizer of most existing access control encryption schemes,this thesis proposes a new lattice-based access control encryption primitive without sanitizer for the requirements of secure access control in Io E environment.The new primitive can not only resist quantum computing attacks,but also reduce the security assumptions for application systems by eliminating the trusted center.Specifically,according to the proposed system model and security model,this thesis first designs a lattice-based subset predicate encryption(SPE)scheme with a formal security proof,and then use the SPE scheme to construct a concrete instantiation scheme of lattice-based access control encryption.Finally,the security analysis and performance evaluation show that the scheme proposed in this thesis meets the security and performance requirements of practical applications on the Internet of Energy.3)This thesis proposes a lattice-based searchable encryption with fine-grained access control for edge computing.To deal with the problem of the lack of access control mechanism of most existing searchable encryption schemes,this thesis proposes a lattice-based searchable encryption primitive with fine-grained access control for the requirement of secure data retrieval and access control in the edge computing environment.The new primitive can resist quantum attacks and support access control.Specifically,according to the proposed system model and security model,this thesis constructs an instantiation scheme based on LWE assumption,and this scheme realizes fine-grained access control for search and decryption.Formal security analysis shows that the scheme is IND-CPA and IND-CKA secure under the LWE assumption.Finally,the theoretical analysis and experimental evaluation show that the scheme proposed in this thesis not only supports richer practical functions,but also has lower computational and communication costs.