Offline Attribute Sharing Methods for Authentication Traffic Reduction and Functionality Enhancement of Wireless LAN Roaming Systems

In Wireless LAN roaming systems such as eduroam and OpenRoaming, ANPs (Access Network Providers) and IdPs (Identity Providers) are generally separated, and there is no standard framework for attribute/consent sharing. Therefore, it is difficult for ANPs to obtain user’s consent for activity analysis or personal data usage which used to be quite important in the business model of conventional Free Wi-Fi systems. On the other hand, as the roaming systems grow, and many users come and leave, the network and the IdPs suffer from a large number of authentication requests from the devices with expired or revoked credentials. This problem would be partly solved if ANPs can receive some attributes from IdPs and suppress unnecessary packets. In this paper, we discuss some methods to share attributes in an offline manner. Some useful applications can be realized by the methods. One of them is delivering user’s preference and consent on data usage. Hash-based Message Authentication Code is employed to protect the attributes from tampering. These methods are also useful in some emerging use cases such as In-Flight Wi-Fi and the Public Wi-Fi in disaster affected areas both of which suffer from the disruption of the backhaul network.