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Applies to

This topic provides a high-level overview of BitLocker, including a list of system requirements, practical applications, and deprecated features.

BitLocker Drive Encryption is a data protection feature that integrates with the operating system and addresses the threats of data theft or exposure from lost, stolen, or inappropriately decommissioned computers.

BitLocker provides the most protection when used with a Trusted Platform Module (TPM) version 1.2 or later. The TPM is a hardware component installed in many newer computers by the computer manufacturers. It works with BitLocker to help protect user data and to ensure that a computer has not been tampered with while the system was offline.

On computers that do not have a TPM version 1.2 or later, you can still use BitLocker to encrypt the Windows operating system drive. However, this implementation will require the user to insert a USB startup key to start the computer or resume from hibernation. Starting with Windows 8, you can use an operating system volume password to protect the operating system volume on a computer without TPM. Both options do not provide the pre-startup system integrity verification offered by BitLocker with a TPM.

In addition to the TPM, BitLocker offers the option to lock the normal startup process until the user supplies a personal identification number (PIN) or inserts a removable device, such as a USB flash drive, that contains a startup key. These additional security measures provide multifactor authentication and assurance that the computer will not start or resume from hibernation until the correct PIN or startup key is presented.

Data on a lost or stolen computer is vulnerable to unauthorized access, either by running a software-attack tool against it or by transferring the computer's hard disk to a different computer. BitLocker helps mitigate unauthorized data access by enhancing file and system protections. BitLocker also helps render data inaccessible when BitLocker-protected computers are decommissioned or recycled.

There are two additional tools in the Remote Server Administration Tools, which you can use to manage BitLocker.

BitLocker Recovery Password Viewer. The BitLocker Recovery Password Viewer enables you to locate and view BitLocker Drive Encryption recovery passwords that have been backed up to Active Directory Domain Services (AD DS). You can use this tool to help recover data that is stored on a drive that has been encrypted by using BitLocker. The BitLocker Recovery Password Viewer tool is an extension for the Active Directory Users and Computers Microsoft Management Console (MMC) snap-in. By using this tool, you can examine a computer object's Properties dialog box to view the corresponding BitLocker recovery passwords. Additionally, you can right-click a domain container and then search for a BitLocker recovery password across all the domains in the Active Directory forest. To view recovery passwords, you must be a domain administrator, or you must have been delegated permissions by a domain administrator.

BitLocker Drive Encryption Tools. BitLocker Drive Encryption Tools include the command-line tools, manage-bde and repair-bde, and the BitLocker cmdlets for Windows PowerShell. Both manage-bde and the BitLocker cmdlets can be used to perform any task that can be accomplished through the BitLocker control panel, and they are appropriate to use for automated deployments and other scripting scenarios. Repair-bde is provided for disaster recovery scenarios in which a BitLocker protected drive cannot be unlocked normally or by using the recovery console.

To find out what's new in BitLocker for Windows, such as support for the XTS-AES encryption algorithm, see the BitLocker section in "What's new in Windows 10." 聽

BitLocker has the following hardware requirements:

For BitLocker to use the system integrity check provided by a Trusted Platform Module (TPM), the computer must have TPM聽1.2 or later. If your computer does not have a TPM, enabling BitLocker requires that you save a startup key on a removable device, such as a USB flash drive.

A computer with a TPM must also have a Trusted Computing Group (TCG)-compliant BIOS or UEFI firmware. The BIOS or UEFI firmware establishes a chain of trust for the pre-operating system startup, and it must include support for TCG-specified Static Root of Trust Measurement. A computer without a TPM does not require TCG-compliant firmware.

The system BIOS or UEFI firmware (for TPM and non-TPM computers) must support the USB mass storage device class, including reading small files on a USB flash drive in the pre-operating system environment.

Important

From Windows 7, you can encrypt an OS drive without a TPM and USB flash drive. For this procedure, see Tip of the Day: Bitlocker without TPM or USB.

Note

TPM 2.0 is not supported in Legacy and CSM Modes of the BIOS. Devices with TPM 2.0 must have their BIOS mode configured as Native UEFI only. The Legacy and Compatibility Support Module (CSM) options must be disabled. For added security Enable the Secure Boot feature.

Installed Operating System on hardware in legacy mode will stop the OS from booting when the BIOS mode is changed to UEFI. Use the tool MBR2GPT before changing the BIOS mode which will prepare the OS and the disk to support UEFI.

The hard disk must be partitioned with at least two drives:

A partition subject to encryption cannot be marked as an active partition (this applies to the operating system, fixed data, and removable data drives).

When installed on a new computer, Windows will automatically create the partitions that are required for BitLocker.

When installing the BitLocker optional component on a server you will also need to install the Enhanced Storage feature, which is used to support hardware encrypted drives.