| 摘要 |
A method of authorising a user of a mobile communication unit to access a service via a visited communication network comprises: ```establishing a secure transport channel between the mobile node and a service access node of the visited network, the channel being identified by the service access node; ```sending an authorisation request from the mobile node to the service access node, incorporating the identity of the service access node into the request, and forwarding the request to an authorisation node of the user's home network. At the authorisation node of the home network, the service access node is authorized, and a user challenge including the identity of the service access node; ```forwarded via the service access node to the mobile unit, where it is ```verifyied whether or not the identity of the secure transport channel matches the identity contained in the received challenge. |
