Reducing Reauthentication Delay in Wireless Networks

When a wireless mobile user is moving across a mobile network or between co-operating networks, the network operators often want to verify the user’s access rights before granting service. The security protocol causes a delay in the network access, which may be much longer than the typical delays caused by mobility management. An alternative would be to provide so called optimistic service before the user has been authenticated or paid for the access. Thus, there is a trade-off between the security of the access control and the quality of service observed by the user. Our aim is to reduce the authentication delay and to enable optimistic access without opening a window for fraudulent access. We present a protocol for the reauthentication of a mobile node when it repeatedly connects to different access points or cooperating wireless networks. The protocol is based on credentials which the mobile receives from access points as a proof of past honest behavior and which it presents when associating with a new access point. It can be implemented with keyed one-way functions that result in low computation and communication overhead both for the mobile and for the network.