Research On Efficient Proxy Re-encryption And Its Application

As a special primitive in public key cryptography,proxy re-encryption is considered as a flexible data access control cryptosystem,which can provide flexible data access authorization for its encrypted data according to user needs.Specifically,the semi-trusted proxy(Proxy)in proxy re-encryption can convert the ciphertext encrypted by the data owner to a ciphertext that can be decrypted by the specified data receiver,and the proxy cannot obtain the information about plaintext and private key.The research on proxy re-encryption technology is of great significance in promoting the realization of secure data sharing.Therefore,this article has conducted in-depth research on proxy re-encryption system and its application,and has obtained the following research results:1)This thesis proposes a proxy re-encryption with equality test scheme,and the application of this solution in cloud-assisted Io T is introduced in detail.Specifically,the scheme allows users to perform ciphertext access control authorization while performing an equality test on ciphertext encrypted with different public keys.The proxy re-encryption scheme satisfies the chosen-ciphertext security,and also has the characteristics of unidirectional,single-hop,non-interactive,and collusion-resistant.In addition,a formal proof of the proposed scheme is given under the random oracle model.At the same time,comparing with the theoretical and experimental simulations of a public key encryption with equality test schemes and public key encryption with keyword search schemes,the comparison result indicate this scheme is efficient and feasible.2)This thesis first proposes a pairing-free proxy re-encryption with equality test and temporary delegation scheme that achieves secure accurately data search,efficient data share and temporary delegation.We detailed introduced the application of this scheme in the cloud-assisted Internet of Vehicle.This scheme not only helps users of the Internet of Vehicles retrieve data and share data,but also allows users to limit the time for data sharing.First,in this thesis,the concept of the pairing-free proxy re-encryption with equality test and temporary delegation scheme is proposed under the random oracle model,and the corresponding security proof is given.Then,this thesis analyzes the performance of the comparison of the computation overhead and communication overhead in the process of encryption,decryption,re-encryption,and equality test.The results show that the proposed pairing-free proxy re-encryption with equality test and temporary delegation scheme greatly reduces the computational overhead in the equality test and re-encryption process.Moreover,the theoretic analysis and experimental simulation reveal that the proposed scheme is efficient and practical.