Embodiments of a distributed index mechanism for indexing and searching for identity information in peer-to-peer networks. In one embodiment, a distributed index may be used to store identity information in a decentralized manner on a plurality of peer nodes. The identity information may be used, for example, to authenticate users. Distributed indexes may allow identity information to be spread across multiple peer nodes so that the load is spread among the various peer nodes. In one embodiment, the distributed index may be a distributed hash table. One embodiment of a distributed index of identity information may be implemented in peer-to-peer networks implemented according to a peer-to-peer platform including one or more peer-to-peer platform protocols for enabling peer nodes to discover each other, communicate with each other, and cooperate with each other to form peer groups and share network resources.