Blockchain-based access control supporting anonymity and accountability

In information security, access control is the selective restriction of access to an online resource or service. One of the most used access control models is Attributebased Access Control, in which access rights are granted to users by evaluating suitable attributes (user attributes, resource attributes, and environment conditions). An important aspect of access control is to guarantee that the identity of the user accessing a service is preserved. In this paper, we deal with this problem and propose a new solution based on a blockchain to ensure that only authorized users can access a service, yet preserving anonymity and unlinkability of their accesses. Moreover, the cooperation among several trusted parties allows the identification of the user accessing a service in case of need.