The Research Of Cloud Data Security Sharing Based On Attribute-based Encryption

The advent of the information age and the era of big data has promoted the vigorous development of cloud computing technology.Cloud computing,as an emerging network application concept,can provide efficient and convenient data storage,sharing and computing services according to the various needs of different types of users.In recent years,successive cloud storage security incidents by cloud service providers have exposed many risks in cloud computing applications in terms of data security storage.After uploading data to a cloud server or a third-party server,the user loses the ownership and management rights of the data,which will cause serious hidden dangers to the user’s data security.Therefore,how to ensure that data can be safely and efficiently stored and shared on cloud platforms is an important research topic.With the rapid development of cloud computing,Attribute-Based Encryption(ABE)has emerged as the times require,which is a cryptographic primitive that can implement fine-grained access control to encrypted data.Compared with the traditional public key encryption scheme,the attribute-based encryption scheme can not only ensure the confidentiality of data,but also realize one-to-many and many-to-many communication between users,and provide flexible access control for data sharing.Especially for the ciphertext policy attribute encryption scheme(Ciphertext-Policy Attribute-Based Encryption,CP-ABE),the data owner decides the ciphertext access policy and realizes the group control of the data receiver,which makes this kind of scheme very suitable.Encrypted storage and fine-grained sharing of data on the public cloud.This thesis mainly studies the anti-quantum attack and revocation problems in cloud computing applications based on ABE.The specific work is as follows:Firstly,most of the traditional CP-ABE schemes are based on two-wire pairing operations,which cannot resist quantum attacks and have low computational efficiency.Aiming at this problem,this thesis designs an attribute encryption scheme based on NTRU lattice,which uses the linear secret sharing matrix as the access matrix to meet the requirements of fine-grained delegated control by the authorizer,and can resist the attack of quantum computing.At the same time,in view of the high computational efficiency of the cryptographic scheme on the lattice,the proposed scheme has the advantages of short key,fast speed,simple operation and small storage space.Based on the Ring-LWE assumption,the proposed scheme is proved under the random oracle model.The program is CPA safe.Secondly,in view of the problem that the existing traditional cloud data encryption scheme cannot resist quantum computing attacks and achieve safe and effective attribute revocation,this thesis proposes a revocable attribute encryption scheme based on NTRU lattice under cloud computing.Fine-grained access control and efficient and secure attribute revocation.In the revocation stage,the key generation agency generates attribute key update and cipher text update components for users whose attributes have not been revoked and the cloud data involved,and finally achieves the purpose of attribute revocation.This thesis formally proves that the scheme can resist quantum computing attacks under a selective security model,and is resistant to collusion attacks carried out by various entities in the cloud.