Research On Privacy Protection Schemes Based On Private Information Retrieval

With the rapid development of cloud computing and big data era,major breakthroughs have been made in data analysis,sharing,and mining,especially the fast popularization and extensive application of network information technology has provided people with more diversified data service options.Science technology and life are integrated,affecting all aspects of people's social life,Today,the Internet has become an indispensable part of people's lives,changing people's lifestyles and work habits.As social life closely combined to the Internet,Various electronic information systems has stored and accumulated mass data,For the limitation of local storage and the urgent need of data sharing,users prefers to upload the local data to the third party cloud servers,in order to save local space and increase data access flexibility.However,the data contains a large amount of personal privacy information,which directly or indirectly reveals personal privacy in the process of storage and sharing,resulting in many security risks.such as personal medical records,search habits and sensitive data with personal characteristics,which will cause serious troubles for the users in case of data breach.Moreover,if the original data is tampered,causing data distortion,it will lead to erroneous analysis and meaningless research.Therefore,while protecting privacy,we must pay more attention to the facticity and availability of data to protect the security of the data itself.At present,how to protect data security and personal privacy,in the process of data sharing,has become the common sense of the whole society and focus of academic researches.Aiming at the personal privacy security issues of users,data self-security in the process of data sharing,this article proposes two schemes of privacy protection,OSBE(Obilivious Signature-Based Envelopes)data retrieval scheme and FIBE(Fuzzy Identity-Based Encryption)data retrieval scheme to protect personal privacy and data security in the process of data sharing,based on the models of OSBE and FIBE,according to the PIR(Private Information Retrieval)protocol.The security of these two schemes bases on CDH(Computational Diffie-Hellman)problem assumption and decisional MBDH(Modified Bilinear Diffie-Hellman)problem assumption respectively.The OSBE data retrieval scheme requires the data owner to upload the encrypted data to the database server and keep the encryption key themselves,and the user needs to obtain the authorized signature of the data owner to decrypt ciphertext.The implementation of the entire program uses symmetrical encryption,and the use of Schnorr signature models also improves the efficiency of data retrieval.The FIBE data retrieval scheme also requires the data owner to upload the encrypted data to the cloud server,which sets up the access policy to control the access objects in the model of the fuzzy encryption system of identity attributes.As long as the user satisfies the access requirements,can users decrypt the data.This scheme not only protects the privacy of the user but also the security of the data itself,and the private key of the user is distributed uniformly by the key generation center based on their own attributes.Both OSBE and FIBE data retrieval schemes are correct and secure,and enhance the privacy of PIR data retrieval protocol to protect the privacy of users further.Compared with PIR protocol,the OSBE and FIBE data retrieval schemes have the following advantages:(1)They enhance the security of users' privacy as well as protect the security of the data itself.(2)They realizes access control of data and has better privacy.(3)Compared with searchable encryption,they are more efficient with less computional complexity for simplifying the ciphertext searching and matching steps.