SFRIC: A Secure Fast Roaming Scheme in Wireless LAN Using ID-Based Cryptography

In a wireless network composed of multiple access points, a long delay during roaming from one access point to another may cause a disruption for streaming traffic. Roaming in wireless LAN is generally composed of two parts, 1) searching for a new access point and 2) performing authentication at the new access point. To reduce the second part delay, we propose an innovative lightweight authentication scheme called SFRIC (secure fast /foaming using ID-based cryptography). SFRIC employs ID-based cryptography to simplify the authentication process. It performs mutual authentication for the mobile client and AP with a 3-way handshake, then generates a PTK (pairwise transient key) directly without pre-distributing PMK (pairwise master key). It does not require contacting an authentication server or exchanging certificates. SFRIC is composed of two phases. In the first phase (the preparation phase), each mobile client obtains a temporary private key from the PKG (private key generator). In the second phase (the roaming authentication phase), mutual authentication and key distribution are performed. Our preliminary analysis indicates that SFRIC can complete the roaming authentication within a period much less than the critical 20 ms threshold, required for maintaining streaming traffic, when the cryptographic operations are performed in hardware.