Access control in wide-area networks

Access control involves maintaining information about which users can access system resources and ensuring that access is restricted to authorized users. In wide-area networks such as the Internet, implementing access control is difficult, since resources may be replicated, the task of managing access rights may be distributed among multiple sites, and events such as host failures, host recoveries, and network partitions must be dealt with. This paper explores the problem of access control in such an environment, and in particular the inherent tradeoff between security, availability, and performance. Techniques for dealing with access control in the presence of partitions are presented and used as the basis for an algorithm that allows application control over these tradeoffs.