A few days after Apple pushed out Mac OS X 10.4.2, which includes client-side changes to AirPort software to support a newer, stronger encryption system, the company released AirPort Software 4.2, incorporating the necessary base station support. Separate versions are available via Software Update or as stand-alone downloads for Mac OS X 10.3.3 through 10.3.9, 10.4.2, and Windows.
This update adds full support for WPA2 (Wi-Fi Protected Access version 2), which provides an access point the capability to offer AES (Advanced Encryption System) encryption keys. Only newer hardware sold starting in late 2002 can handle the computation required, so original AirPort cards and base stations cannot be updated to handle WPA2.
The original WPA, which appeared as an update to Panther, offers a superior encryption algorithm and other improvements for Wi-Fi security for AirPort Cards, AirPort Extreme Cards, and AirPort Extreme and Express Base Stations (see "AirPort Firmware Updates Fix Major Bugs" in TidBITS-760). WPA2 is a further refinement - technically, it's the full ratified version of IEEE 802.11i - that works only with AirPort Extreme Cards when connecting to WPA2 Personal- or WPA2 Enterprise-configured networks. AirPort Cards cannot support WPA2 because of limitations in silicon; WPA was designed to be backward compatible with early 802.11b cards, such as the AirPort Card.
Some businesses have been waiting until WPA2 was released before deploying their Wi-Fi networks because of its government-grade encryption. WPA2 also has a few features that add to WPA, such as fast reauthentication, which allows a laptop using WPA2 Enterprise - a system that uses a unique login that produces a unique session key - to roam without a long delay when moving from base station to base station.
AirPort 4.2 includes new versions of AirPort Admin Utility and AirPort Setup Assistant, and firmware updates for both AirPort Extreme and AirPort Express Base Stations.
This update brings Apple current with the rest of the industry. Interestingly, older WEP (Wired Equivalent Privacy) encryption is all that is available for the software base station created through the Create Network command in the AirPort status menu. WEP is cryptographically broken; one hopes Apple will eventually offer at least WPA for improved security of ad hoc networks.