Research And Application Of Certificateless Encryption Scheme With Privacy Protection Function

With the rapid development and wide application of cloud computing technology,more and more users are storing their private data on cloud servers,which also brings a series of problems related to data privacy and security,such as privacy leakage,data tampering,malicious attacks,etc.Public key encryption technology has become one of the effective means to protect users’ private data,but when users upload ciphertext to cloud servers,it brings the problem of difficulty in retrieving ciphertext information.Searchable encryption technology meets users’ needs for retrieving encrypted data in the cloud,but in traditional public key cryptographic systems,most searchable encryption schemes suffer from certificate management and key escrow problems.In the Internet of Vehicles,data are outsourced to cloud servers for storage and processing when communicating between entities,and the semi-trustworthy characteristics of cloud servers lead to privacy leakage of outsourced data,while the shortcomings of existing searchable encryption schemes applied to the Internet of Vehicles are mainly reflected in two aspect of security and low retrieval efficiency.In order to solve the above problems,this thesis proposes three encryption schemes with privacy protection function for cloud storage environment,combined with Internet of Vehicles application scenarios,working as follows:(1)A group signature authentication encryption scheme with designated recipients is proposed to address the problems of privacy leakage and traceability of communication data when users communicate in the cloud environment.By combining group signature with public key cryptography,multiple users share keys without the intervention of certificate authorities,which reduces system complexity and computational overhead while ensuring data confidentiality,integrity and traceability.The result analysis shows that the scheme satisfies signature unforgeability and has high computational efficiency,making the user communication environment safe and secure.(2)In response to the problems that most searchable encryption schemes do not support ciphertext retrieval by multiple users and are vulnerable to keyword guessing attacks launched by internal and external attackers,we propose a searchable encryption scheme that supports license authorization without certificates in a cloud environment.Combined with proxy re-encryption technology,it enables users to obtain accurate data request results without disclosing private information to the cloud server.In addition,the authorization process of the data service center ensures data security and enables revocability of user authorization.The result analysis shows that the scheme is resistant to internal or external keyword guessing attacks,has better performance in terms of computation and communication efficiency.(3)An efficient certificateless searchable encryption scheme with privacypreserving functions is proposed for application in the Internet of Vehicles environment where wireless communication between entities is susceptible to attacks and thus leads to vehicle privacy leakage.The storage and search functions are assigned to different servers,where the search server needs to authenticate the vehicle users and only allows data search services for legitimate users,increasing the availability and security of the server while avoiding the risk of single point of failure and data leakage.The analysis of the results shows that the scheme has high security and computational efficiency,and has practical value in the Internet of Vehicles application scenario.