Deﬁnition: Encryption is a security measure in which information is encoded or scrambled so that it cannot be read unless the recipient knows the decoding mechanism, or key. Encryption is used in many common systems, to protect passwords during authentication, to protect the data inside network messages, and to protect data stored in ﬁles.
BitLocker Drive Encryption:
Windows BitLocker is a security feature of Windows 7 and Windows Server®2008. This security feature provides full disk encryption protection for your operating system as well as all the data stored on the operating system volume. BitLocker encrypts all data stored on the operating system volume and is conﬁgured by default to use a Trusted Platform Module. This feature ensures the protection of early startup components and locks any BitLocker-secured volumes in order to prevent access or tampering when the operating system is not running.
The Encrypting File System (EFS) is a ﬁle-encryption tool that enables users to encrypt ﬁles on an NTFS-formatted partition on a Windows systems. When you encrypt ﬁles or folders with EFS, only the user who encrypted the ﬁle or folder can open it and read the contents. EFS is a good way to protect ﬁles on portable computers that can be lost or stolen, because, unlike NTFS permissions, EFS can protect the data even if the attacker accesses the data directly, using a sector editor.