A system and method for securely processing identity information. For example, in one embodiment of the invention, a first user is registered on an identity service with one or more identification (ID) codes and a token. In response to a query from a second user to connect with the first user, a query signature is generated using the one or more ID codes and token of the first and second users, and a timestamp. The query signature is usable by network services to authenticate communication between the first and second users on the network over a specified period of time. In another embodiment, user ID codes and tokens are cached on mobile devices and/or a system cache to improve performance. The validity of the cached data is determined by calculating a fingerprint which, in one embodiment, is a hash of the ID code, token and a timestamp.