Extending the WebID Protocol with Access Delegation

The WebID protocol enables the global identi cation and authentication of agents in a distributed manner by combining asymmetric cryptography and Linked Data. In order to decide whether access should be granted or denied to a particular WebID, the authenticating web server may need to retrieve other pro les and linked resources to work out e.g. if the requesting agent is member of an authorized group. If these resources are required to be publicly available for the server to access it, then this would be a major privacy limitation on a linked Social Network. In this paper we explore di erent ways in which an agent can act as a user and we propose an extension to the WebID protocol which allows for delegation of access authorization from a WebID to a third party, e.g. allowing a server to be able to act on behalf of its users. This extends the range of application scenarios where WebID authentication can be e ciently deployed while increasing privacy.