Microsoft has released more information about Windows Vista with the latest Community Technology Preview (CTP).

The December CTP, known as build 5270, will reach about 500,000 people various avenues including the Microsoft Developer Network (MSDN) and TechNet. Security, performance and mobility as the key themes, the company said.

"We are on a path to be code-complete by the end of 2005," said Shanen Boettcher, Microsoft senior director in the company's Windows client group. A code-complete CTP is expected in early 2006, with the general release version of Vista set for the second half of next year.

With the December CTP, Windows AntiSpyware has been renamed Windows Defender. It features improved detection and removal of spyware and malware as well as a redesigned user interface, Boettcher said. Microsoft describes the anti-spyware offering in the December CTP as a functioning early preview of what will be in the final version.

Also offered in the CTP is BitLocker Drive Encryption, formerly known as full-volume encryption. It provides hardware-based data protection to address the issue of data being accessed from lost or stolen machines. The entire Windows system volume is encrypted to prevent unauthorised access.

Users of the new CTP can apply Group Policy to block installation of removable storage drives. "This has been a big concern for folks in terms of data leakage," Boettcher said.

Internet Explorer gets support for international domain names as well as protection from spoofing of these domain names. Advancements in firewall software include bi-directional filtering. Rules set in the Windows Service Hardening platform are enforced to limit the file, registry, and network access. Advanced IPSec is offered, integrated into a single management console with firewall management.

To improve performance and mobility, a single button is being used as an on/off control while a Windows SuperFetch algorithm caches items used most frequently. USB Flash drive can be used to provide additional memory employed by SuperFetch.

The new user interface in build 5270 features improvements in design elements and some consumer-oriented features. The December CTP includes Windows Media Player 11, featuring improvements to the look and feel.

An early version of Aero is highlighted, as well. Aero encompasses a new design philosophy that includes a translucent "glass" appearance of open windows as well as smoother transitions between windows. A re-designed start menu also is part of Aero.

One analyst described the December CTP as a progression toward the final version.