Abstract: An integrated authentication service is described which may receive a bundled request from one or more clients. One or more of the described techniques may be utilized to provide, in response to a single bundled request, a token for proof of identity and a certificate for establishing secure communications.

Abstract: Embodiments of multiple security token transactions are described herein. One or more of the described techniques may be utilized to provide, in a single request and response, an authentication token and a plurality security tokens for proof of identity at respective service providers.

Abstract: Secure site-to-site transactional communication between at least two network servers coupled to a data communication network, including secure registration by an authentication server associated with a multi-site user authentication system. A network server receives a request via a browser f of a client computer. In response, the network server initiates a transaction with the authentication server and defines a data structure, such as a query string, associated with the transaction. The network server also generates a digital signature of the data structure and then adds it to the data structure before directing the client computer from the network server to the authentication server with the data structure and the added digital signature. The network server also adds an index to the data structure. The index is associated with the transaction and unique, per transaction, to the network server initiating the transaction.