What is BitLocker?
BitLocker is an encryption and security program for computer hard drives that is published by Microsoft Corporation as a native application in the operating system versions Windows 7 Enterprise and Ultimate, Windows Vista Enterprise and Ultimate, and Windows Server 2008, R2 and 2012. It is a drive security and encryption program that protects drive contents and data from offline attacks.
BitLocker is primarily designed to prevent a user's data from being viewed, extracted, or retrieved if a drive is stolen. It does not protect a system when it is 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 a 256-bit key to encrypt disk volumes. It protects the data if a hard drive is stolen and used on another computer, or if someone has physical access to the drive. To access the drive in offline mode, BitLocker requires a recovery key. BitLocker is usually aimed at individual users who could be the victim of computer / laptop theft.