Research On Identity-based Encryption With Equality Test

The development of the cloud computing industry lead to new forms of data storage and outsourcing computing.Equality test has become the central issue of the researchers owing to its flexible applications in searching over encrypted data with multiple public keys.The above mentioned cryptographic primitive means that the cloud server can determine whether the different ciphertexts corresponding to the same message without decrypting them.Identity-Based Encryption with Equality Test(IBEET)combines the identity-based encryption and equality test technology,while congesting their respective advantages.However,in IBEET system,the most schemes are proved secure in the random oracle model,which relies on ideal security assumption,so how to construct an efficient IBEET scheme in the standard model is still a challenge.On the other hand,the traditional IBEET constructions only allow the cloud server to execute the equality test between two ciphertexts among test algorithm,and how to improve the flexibility of equality test also needs to be studied.In response to the above problems,we mainly focus on the IBEET system,the specific research work of our paper is as follows:(1)Identity-Based Encryption with Equality Test Supporting Multiple Authorizations in the Standard Model(IBEET-MA).We summarize the advatanges and the shortcmings of the exsiting IBEET schemes,and state that Lee et al's construction is the only IBEET construction in the standard model,which suffers from low efficiency and single authorization.To remedy this problem,we firstly present an Identity-Based Encryption with Equality Test Supporting Multiple Authorizations in the Standard Model,the size of the private keys and the ciphertexts are constant.Compared with Lee et al's construction,we reduce the number of pairing operations in Enc,Dec and Test algorithms,and obtain significant improvement in computational efficiency.At the same time,our construction supports three types of authorizations,which enables users to control the authorization mechanism flexibly.Finally,we give the security analysis of the construction against two types of adversaries respectively in the standard model.(2)Identity-Based Encryption with Equality Test on Multi-Ciphertexts(IBE-MET).We indicates that the traditional IBEET constructions only allow the cloud server to execute the equality test between two ciphertexts among test algorithm.To remedy this problem,we present a contruction which permits cloud server to execute the equality test between multiple ciphertexts among test algorithm and greatly improves the efficiency of equality test.Besides,the size of ciphertexts in our construction is constant.In addition,we state that the cloud server can only obtain 1 bit information among Test algorithm,which improves the security and remedies the disadvantage of high computational costs.Finally,we give the security analysis of the construction against three types of adversaries respectively in the random oracle model.