ESTABLISHING A COMMUNICATION SESSION
A secure communication session is established between a first endpoint (50) and a second endpoint (42). The first endpoint (50) can contact the second endpoint (42) via a first communication network (20) and via a second communication network (30). The first communication network (20) is more trusted than the second communication network (30). The first endpoint (50) determines that a secure communication session is required. A security association is established between the endpoints for the communication session on a connection (11) via the first communication network (20). Service is received on a connection (12) via the second communication network (30) using the previously established security association. The step of establishing a security association can comprise authenticating the second endpoint and negotiating a shared secret and the step of receiving service on a connection (12) via the second communication network (30) can occur without any further negotiation of key material or authentication between the endpoints via the second communication network (30).