An Efficient and Usable Multi-show Non-transferable Anonymous Credential System

In an anonymous credential system a user can prove anonymously the possession of credentials to a service provider. Multi-show and non-transferability are two important properties of such systems. More precisely, in a multi-show system the same credential can be used more than once without threatening anonymity, moreover, lending of non-transferable credentials is inconvenient. In this paper we give a construction for multi-show non-transferable credentials for which the owner can prove that the credentials satisfy access control policies expressed by means of linear boolean formulae.