Revocable Public Key Encryption Scheme In A Cloud Environment

In recent years,Internet of Things has developed rapidly and has been widely used in various fields such as smart power grids,smart medical treatment and smart furniture.As an intelligent application of Internet of Things in intelligent transportation,Internet of Vehicles improves public safety and traffic efficiency by pushing information about road and traffic conditions to vehicles,helping them choose better travel routes.In practical scenarios,in order to ensure data security and save resources,the data permissions of illegal vehicles should be effectively revoked.In addition,as technologies such as cloud computing and big data analysis continue to mature,cloud medical treatment makes it more convenient to create,collect,and manage vast amounts of personal health records of patients.However,health information is considered highly sensitive and should not be misused by malicious users.Therefore,in the public cloud environment,it is of great significance to study how to effectively revoke the authority of illegal vehicles and how to dynamically process a large number of patients’ personal health data.The research content and main achievements of this paper are as follows:(1)We propose a revocable and anonymous aggregate encryption(RAAE)scheme to address the above issues and efficiently send different messages to multiple receivers.In our work,there exists a trusted third party responsible for revoking the illegal vehicles’ right to get the information and a roadside unit encrypts multiple messages into one ciphertext.Different legal vehicles can decrypt the ciphertext with their own private keys to obtain the corresponding plaintext,and the plaintext obtained by different vehicles is different.Our scheme does not involves bilinear pairing and hash-to-point operations,and is shown to be indistinguishable and anonymous against chosen ciphertext attacks under the standard model.Furthermore,we analyze the performance of communication costs and computation costs,and the result of comparison shows that our scheme is suitable for Io V systems.(2)Aiming at the problems of privacy exposure,data security,flexible access of storage modules in medical systems,we present a privacypreserving certificateless broadcast encryption with authorization suitable for the personal health record system,which effectively solves the above problems and avoids the defects of key escrow.In our work,users outsource their encrypted data to the cloud server and reallocate data accessing rights of recipients through an authorization set,sharing with a group of authorized receivers in a secure and efficient manner.In addition,it is shown to be capable of achieving both plaintext confidentiality and receiver anonymity under the random oracle model.Moreover,the experimental result shows that the proposed scheme enjoys low computational and communication overhead,indicating the feasibility and practicality of the scheme.