Soner Sevinc will present his preFPO on Thursday March 8 at 9AM in Room 402. The members of his committee are: Larry Peterson, advisor; Jennifer Rexford and Andy Bavier, readers; David Walker and Michael Freedman, nonreaders. Everyone is invited to attend his talk. His abstract follows below. ------------------------------------- Discovering and authorizing resources dispersed across autonomous organizations is a challenge for federations as they scale. We introduce a delegation logic for federation to address the problem of authentication and authorization in large scale. A Federation Policy Language (FPL) is used to express this logic, and allows expression of custom security and allocation policies. One distinguishing feature of FPL is that it utilizes a DHT for storage/retrieval of certificates to increase fault-tolerance, efficiency and expressivity in proof constructions. Our contract based discovery and allocation system, CODAL, performs policy-driven peer discovery and collaborative resource discovery/allocation to address two problems: (1) participants in a federation can be unknown, and (2) their resource information and policies can be private. We evaluate our design in PlanetLab, emulating a realistic federation based on PlanetLab usage logs. Results show that our system is capable of discovering and allocating resources in a large scale federation, fulfilling a request from tens of organizations. We also show allocation policies are successfully enforced by our language,and explore run-time characteristics of the FPL proof construction process, and investigate certificate retrieval in terms of time and incurred system load.