Is That You? Authentication in a Network without Identities

Most networks require that their users have "identities", i.e. have names that are fixed for a relatively long time, unique, and have been approved by a central authority (in order to guarantee their uniqueness). Unfortunately, this requirement, which was introduced to simplify the design of networks, has its own drawbacks. First, this requirement can lead to the loss of anonymity of communicating users. Second, it can allow the possibility of identity theft. Third, it can lead some users to trust other users who may not be trustworthy. In this paper, we argue that networks can be designed without user identities and their drawbacks. Our argument consists of providing answers to the following three questions. (1) How can one design a practical network where users do not have identities? (2) What does it mean for a user to authenticate another user in a network without identities? (3) How can one design a secure authentication protocol in a network without identities?