EAP
A general protocol for authentification used with Point-to-Point Protocol(PPP) on wired networks and Wi-Fi Protected Access (WPA) on wireless network. Based on public-key encryption algorithms, it supports multiple authentification methods, such as token cards Kerberos, one-time passwords, certificates, public key authentification and smart cards. IEEE 802.1x specififies how EAP should be encapsulated in LAN frames.
More: Extensible Authentication Protocol