Revocable Attribute-Base Scheme with Enhanced Security and Privacy for Healthcare Data Sharing

Cloud-assisted healthcare system is playing an increasingly important role in smart healthcare delivery. Before outsourcing patients information to the cloud, the sensitive information contained therein is usually encrypted to protect privacy. However, traditional encryption methods have limitations in addressing dynamic control of data access. To address this issue, we propose an attribute-based secure sharing scheme that supports attribute revocation for flexible data sharing in cloud-assisted healthcare systems. We tag the user’s identity using a collection of attributes, leading to dynamic change in the user’s identity translating into the control over the collection of attributes. We design a dual revocation mechanism combining direct and indirect revocation methods to cope with user revocation as well as attribute revocation. To accomplish user revocation, we use a proxy server to provide an identity proof based on Merkel tree, resulting that any revoked user cannot be authenticated through the cloud. To improve the efficiency of attribute revocation, we build the attribute tree for each attribute to record the users who hold this attribute, and use the KUNodes algorithm to achieve efficient attribute revocation. We conduct a series of experiments on our scheme to evaluate its effectiveness. The experimental results show that our scheme can achieve the revocation goal.