Security analyses of a data collaboration scheme with hierarchical attribute-based encryption in cloud computing

With the prevalence of cloud computing, users store and share confidential data in the cloud while this approach makes data security become an important and tough issue. To ensure data security, cloud service providers must provide efficient and feasible mechanisms to provide a reliable encryption method and a suitable access control system. In order to realize this ideal, Huang et al. proposed a data collaboration scheme with hierarchical attributebased encryption. After analyzing Huang et al.'s scheme, we find that one weakness exists in their scheme such that the semi-trusted cloud service provider can decrypt the protected data to obtain the plaintext. Data confidentiality is not ensured as claimed. In this paper, we will explicitly indicate how this weakness damages Huang et al.'s scheme. © 2020, Femto Technique Co., Ltd.