Systems and processes are described for establishing and using a secure channel. A shared secret may be used for authentication of session initiation messages as well as for generation of a private/public key pair for the session. A number of ways of agreeing on the shared secret are described and include pre-sharing the keys, reliance on a key management system, or via a token mechanism that uses a third entity such as a hub to manage authentication, for example. In some instances, the third party may also perform endpoint selection (e.g., load balancing) by providing a particular endpoint along with the token.