Research On Public Key Encryption With Keyword Search Techniques In Cloud Environments

In recent years,with the increasing development of cloud computing technology,massive datasets continue to emerge,encouraging more and more data users to actively upload them to the third-party cloud server for storage.Data users not only get rid of local storage constraints,but also reduce the complexity of data management.However,as the cloud server is not fully trusted and users lost their capabilities to control data,data security will be seriously threatened.In order to prevent the leakage of user data,the most common method is that the user first encrypts the stored data before outsourcing to the cloud.Although encryption technology can ensure the confidentiality of data,it also brings inconvenience of data access and processing.To address this issue,public key encryption with keyword search(PEKS)as an efficient method was proposed,which enables users to search queries over encrypted data while guaranteeing the privacy of user data.In this thesis,we focus the research on public key encryption with keyword search techniques in cloud environments.This thesis analyzes six kinds of PEKS techniques,and mainly focuses on the searchable public key encryption algorithm based on attribute-based encryption to achieve fine-grained access control over shared data,and two efficient PEKS schemes was proposed.The detailed research work and innovations can be summarized as follows.(1)We design an efficient public key encryption with keyword search based on ciphertext-policy attribute-based encryption(PEKS-CPABE)scheme that is more suitable for the cloud environment,which not only achieves fine-grained access control but also supports keyword search over shared data at the same time.First,we give the system model,algorithm definition,and the concrete construction.Then,we give a rigorous security proof of the ABMKS-SM scheme under the random model.Finally,we evaluate the performance of the scheme.Compared with the state-of-the-art attribute-based keyword search scheme and the recent improved scheme,the efficiency of the proposed scheme is illustrated by theoretical analysis and experimental analysis.(2)We propose a novel attribute-based multi-keyword search for shared multi-owner(ABMKS-SM)scheme to support both enhanced access control and multi-keyword search over shared data.Most importantly,it can be suitable for shared multi-owner scenarios.Based on the random oracle model,we prove that our scheme is indistinguishability secure against an adaptive chosen keyword attack(IND-CKA).Finally,we evaluate the performance of our scheme in terms of functional,theoretical,and experimental analysis,and further demonstrate the efficiency and practicality of our scheme in the shared multi-owner setting.