1. Field of the Invention
The present invention applies to the field of hardware authentication, in particular to time certification in a wireless network.
2. Description of the Prior Art
Hardware authentication, also sometimes referred to as entity authentication, is the process of verifying a claimed or presumed identity. In the context of a wireless access network, hardware authentication is used to verify that a an entity is indeed the entity it is claiming to be. For example, a hardware authentication can verify that a terminal claiming to have a certain MAC address really has the claimed MAC address. Without hardware authentication, unauthorized user terminals could steal the resources of the wireless access network, and uplink and downlink communications between legitimate user terminals and access points may be intercepted and eavesdropped.
Hardware authentication in wireless networks is currently accomplished by time varying challenge-response protocols. In a typical challenge-response protocol a claimant proves its identity to a verifier by demonstrating knowledge of a secret known to be associated with the claimant.
One problem with challenge-response protocols is that the verifier needs access to a secure database to identify the secret the claimant should have. Furthermore, such protocols require several message exchanges and on-the-fly encryption that can slow down network access.
User terminals getting their sense of time from access points can cause another problem in some wireless access networks. The access point can get their time from wired networks, or the Global Positioning System. Before the terminal can authenticate the access point it may need a sense of time. However, the access point is not yet authenticated. Thus, its time reference cannot always be trusted.