Key aggregation encryption method capable of being revoked in cloud environment

Abstract

The invention discloses a key aggregation encryption method capable of being revoked in a cloud environment. A user revocation supporting function is added on the basis of a key aggregation mechanism, and a user dynamic management function on the key aggregation mechanism is improved. According to the method, not only is user key management simplified, but also different decryption permissions are granted to different users. Ciphertext is updated through a cloud storage server to achieve user permission revocation; when one user is revoked, the legal users do not need to update a key, and therefore the burden of an authority is reduced; and the ciphertext can be verified and updated, and it is guaranteed that user revocation is effectively executed. Security proof shows that on the basis of a Weak DHDHE assumption, it proves that the proposed method achieves non-adaptive selection plaintext security under a standard model. Performance analysis shows that by means of the method, the length of the user key and the ciphertext is kept to be O(1), the length of systematic public parameters is kept to be O(log N), more efficient user revocation efficiency is achieved, and control over access permissions of the users is effectively achieved.

Description

technical field [0001] The present invention relates to the related technical field of key aggregation mechanism, in particular to a revocable key aggregation encryption method in a cloud environment. Background technique [0002] With the continuous development of cloud computing technology, a new data storage mode, namely cloud storage, has attracted great attention. Cloud storage is a data storage service technology derived and developed from cloud computing. It saves local data in the online storage space provided by cloud service providers through the network. It is low-cost, easy-to-use and highly scalable. Advantages, meet the needs of massive data storage, and provide data sharing services, has become a key area of ​​information storage development. [0003] However, while cloud storage brings great convenience to people, it also brings new security issues and challenges. Because in the cloud computing environment, the cloud server is not completely trustworthy, an...

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Problems solved by technology

However, the system public parameter length of Chu et al.'s scheme is Ο(N), and no specific security proof is provided

In 2015, Sikhar et al. proposed a revocable key aggregation encryption scheme for the first time in the document "Dynamic Key-Aggregate Cryptosystem on Elliptic Curves for Online Data Sharing", which realized the user's dynamic revocation function, but in this scheme, once When user revocation occurs, all legitimate users need to update their keys, which brings expensive key update overhead

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