BitLocker Hard Drive Encryption
A hard drive encryption tool in Windows Vista Enterprise and Ultimate. BitLocker addresses threats of data theft or disclosure from lost, stolen or inappropriately decommissioned PC hardware. BitLocker works by preventing a thief who boots another operating system or runs a software hacking tool from breaking Windows Vista file and system protections or performing offline viewing of the files stored on the protected drive. The feature uses a Trusted Platform Module to protect user data and to ensure that a PC running Windows Vista has not been tampered with while the system was offline. BitLocker combines drive encryption and integrity checking of early boot components. [Adapted from Microsoft Windows Vista]
Also see Windows Vista.