Traditionally, Grid users have been identifiable and traceable beyond reasonable doubt by their digital certificates. However, grids are used in an ever-increasing variety of contexts and thus, the number of usage scenarios has augmented accordingly. In bio-medicine and other health-related fields a need for anonymous access to grid resources has been identified. Anonymous access to resources prevents the resource owners and other external parties from tracing the users and their actions. Such anonymity of resource usage in grids is needed above all in commercial contexts, e.g. protecting the development process of a new medicine by anonymizing the accesses to medical research databases.