Research On NTRU-Based Proxy Re-Encryption And Its Application

With the rapid development of cloud storage,more and more data owners are encouraged to outsource their data.However,security and privacy issues have always been the main reasons that hinder the popularity of cloud storage.In cloud storage,the main concern is to provide security for end users to protect files or data from being accessed by unauthorized users,and the cloud itself cannot obtain any private information from the data.In order to meet the above security requirements,this paper uses a proxy re-encryption scheme to protect cloud storage security.In the proxy re-encryption scheme,a semi-trusted proxy uses the re-encryption key to convert the ciphertext encrypted by the public key of the authorizer into a ciphertext that can be decrypted by the private key of the authorized person,and during the conversion,the semi-trusted proxy cannot obtain private information.Previous proxy re-encryption schemes are mostly based on discrete logarithm problems or large integer factorization problems.With the rapid development of quantum computer technology,the possibility of solving these problems in polynomial time is rapidly increasing.Therefore,it is necessary to find a proxy re-encryption scheme that can resist quantum attacks.David et al.proposed the NTRU-based proxy re-encryption scheme for the first time.This scheme is based on the NTRU lattice and can resist quantum attacks,but this scheme cannot resist collusion attacks and has multi-hopping.This paper proposes a proxy re-encryption scheme based on NTRU that can resist collusion attacks in response to the threats faced by cloud storage and the vulnerability of the David scheme that cannot resist collusion attacks,and then designs a cloud data security sharing scheme based on this scheme.The main contributions are as follows:(1)Analysis of existing proxy re-encryption schemes is mostly based on traditional number theory problems,which not only has a large computational overhead,but also cannot resist quantum attacks.In this regard,this paper proposes a proxy re-encryption scheme based on NTRU anti-collusion attacks.Since the scheme is constructed based on NTRU lattice,it can resist quantum attacks.In addition,the scheme improves the re-encryption key generation algorithm to make it resistant to collusion attacks,and has bidirectionality and single hop.The correctness and security of the scheme are analyzed.Comparison and analysis with other programs show that this program has higher security and better performance.(2)The security problems in the cloud storage system are analyzed,and a cloud data security sharing scheme is designed in conjunction with the scheme proposed in this article.In this solution,the data owner chooses different encryption methods according to different security requirements or performance requirements.The proxy is limited to the ability to re-encrypt,and the data user can check whether the data has been tampered with.Therefore,this solution can not only ensure the security of cloud data,but also can check whether the data has been tampered with and limit the ability of the agent.Finally,it also analyzes its performance to ensure that it can meet the actual use.(3)This article summarizes the two schemes proposed in this paper,deeply studies the NTRU-based proxy re-encryption scheme and its application in cloud storage,and analyzes the shortcomings of the scheme.