Encrypting File System
This feature is included in the following editions of Windows Vista:
A key security feature of the Business, Enterprise, and Ultimate editions of Windows Vista, Encrypting File System is useful for user-level file and folder encryption. For example, if two users are sharing a computer, an administrator can use Encrypting File System to encrypt each user's data to make it unavailable to the other user. For network file and folder encryption, Windows Vista enhances Encrypting File System management by enabling administrators to store Encrypting File System keys on smart cards.
IT administrators can use Group Policy in Windows Vista to block the use of removable storage devices, such as USB flash drives and external hard disks, to help prevent the compromise or theft of corporate intellectual property and sensitive data.