Identifying peers using a self-contained directory

PGP’s “web of trust” approach provides basic identification facilities. One benefit of this approach is that it tries to lower the infrastructure requirements such that, for example, no certification authorities are required. In this paper we also pursue this objective but take it even further. We present a self-contained P2P-based directory that provides similar guarantees for identification as PGP, and like PGP requires no dedicated, third-party infrastructure. The participating peers provide the infrastructure along with their normal operation. But unlike PGP it does not require out-of-system mechanisms to disseminate the public key. Instead we exploit properties of the underlying P2P system to ensure correct key publication and retrieval by probabilistic quorums. We argue that this is an efficient and more reliable mechanism compared to web-of-trust approaches.