Apple AirPort Networks - Manual (Page 12)

12 Chapter 2 AirPort Security
The EAP protocol known as TLS (Transport Layer Security) presents a user’s information
in the form of digital certificates. A user’s digital certificates can comprise user names
and passwords, smart cards, secure IDs, or any other identity credentials that the IT
administrator is comfortable using. WPA uses a wide variety of standards-based EAP
implementations, including EAP-Transport Layer Security (EAP-TLS), EAP-Tunnel
Transport Layer Security (EAP-TTLS), and Protected Extensible Authentication Protocol
(PEAP). AirPort Extreme also supports the Lightweight Extensible Authentication
Protocol (LEAP), a security protocol used by Cisco access points to dynamically assign a
different WEP key to each user. AirPort Extreme is compatible with Cisco’s LEAP security
protocol, enabling AirPort users to join Cisco-hosted wireless networks using LEAP.
In addition to TKIP, WPA2 supports the AES-CCMP encryption protocol. Based on the
very secure AES national standard cipher, combined with sophisticated cryptographic
techniques, AES-CCMP was specifically designed for wireless networks. Migrating from
WEP to WPA2 requires new firmware for the AirPort Extreme Base Station (version 5.6 or
later), and for AirPort Express (version 6.2 or later). Devices using WPA2 mode are not
backward compatible with WEP.
WPA and WPA2 have two modes:
 Personal mode, which relies on the capabilities of TKIP or AES-CCMP without
requiring an authentication server
 Enterprise mode, which uses a separate server, such as a RADIUS server, for user
authentication
WPA and WPA2 Personal
 For home or Small Office/Home Office (SOHO) networks, WPA and WPA2 operates in
Personal mode, taking into account that the typical household or small office does
not have an authentication server. Instead of authenticating with a RADIUS server,
users manually enter a password to log in to the wireless network. When a user
enters the password correctly, the wireless device starts the encryption process using
TKIP or AES-CCMP. TKIP or AES-CCMP takes the original password and derives
encryption keys mathematically from the network password. The encryption key is
regularly changed and rotated so that the same encryption key is never used twice.
Other than entering the network password, the user isn’t required to do anything to
make WPA or WPA2 Personal work in the home.