Application-layer design patterns for accountable–anonymous online identities

Both anonymity and accountability play important roles in sustaining the Internet's functionality; however, there is a common misconception that increasing the anonymity of Internet identities requires diminishing their accountability, and vice versa. This paper argues that by implementing accountability mechanisms and anonymity protections at the application layer of the Internet, rather than the network layer, it is possible to develop a variety of different types of accountable–anonymous virtual identities, tailored to meet the needs of numerous, diverse online applications. Examples are drawn from several identity mechanisms used by existing applications and general design patterns for implementing accountability are discussed, with particular emphasis on designing identity investment–privilege trade-offs, conditional anonymity schemes, and aggregated, identity management systems, as well as the role of scoped identities and linked identities in promoting online accountability.