Definition - What does BitLocker mean?
BitLocker is a computer hard drive encryption and security program released by Microsoft Corporation as a native application in its Windows 7 Enterprise and Ultimate editions, Windows Vista Enterprise and Ultimate, and Windows Server 2008, R2 and 2012 operating system versions. It is a drive security and encryption program that protects drive content and data from any offline attack.
Techopedia explains BitLocker
BitLocker is primarily designed to prevent a user’s data from being viewed, extracted or retrieved in case a drive is stolen. It doesn’t protect a system when it’s running because the online/operational/live protection is maintained by the operating system. BitLocker uses an AES encryption algorithm with a 128-bit key or 256-bit key to encrypt disk volumes. It protects the data when a hard drive is stolen and is being used on another computer or when someone has physical access to the drive. To access the drive in an offline mode, BitLocker requires a recovery key. BitLocker is generally aimed toward individual users who may fall prey to computer/laptop theft.