Generate Bitlocker Recovery Key From Password
- Generate Bitlocker Recovery Key
- Generate Bitlocker Recovery Key From Password Windows 7
- How To Find My Bitlocker Recovery Key
- Generate Bitlocker Recovery Key From Password Key
Updated: May 18, 2017
Applies To: Windows 8.1, Windows Server 2012 R2, Windows Server 2012, Windows 8
Organizations can use BitLocker recovery information saved in Active Directory Domain Services (AD DS) to access BitLocker-protected data. Creating a recovery model for BitLocker while you are planning your BitLocker deployment is recommended.
This article assumes that you understand how to set up AD DS to back up BitLocker recovery information automatically, and what types of recovery information are saved to AD DS.
This article does not detail how to configure AD DS to store the BitLocker recovery information.
- The BitLocker recovery key is a special key that you can create when you turn on Bitlocker Drive Encryption for the first time on each drive that you encrypt. The recovery key is what enables Bitlocker to recover things for you when you forgot your BitLocker password.
- The password recovery process is time-consuming and depends on the password complexity, any knowledge about the password, and your hardware resources available for password recovery, such as GPUs and availability of distributed computing. As a result, the recovered original password can be used to mount the BitLocker volume.
- (Bitlocker to Go) I am sure that the password is 85% correct but Bitlocker doesn't accept it. I don't have on my outlook account or on my computer the recovery key. The recovery key has been erased when I've reinstalled the OS. Is there a solution for this problem? Can Microsoft help me generate a recovery key with the key ID?
- The user can type in the 48-digit recovery password. A domain administrator can recover the password from Active Directory Domain Services if that is where the password was stored. Employ a data recovery agent to unlock the drive. The drive must be mounted as a data drive in order for the agent to unlock it.
- To start, type BitLocker in the Cortana search box on the taskbar, and then click Manage BitLocker from the result to open the BitLocker Drive Encryption control panel. Click on the link stating “Back up your recovery key” next to the encrypted drive. It will prompt you to choose how to store the recovery key.
This article contains the following topics:
What is BitLocker recovery?
BitLocker recovery is the process by which you can restore access to a BitLocker-protected drive in the event that you cannot unlock the drive normally. In a recovery scenario you have the following options to restore access to the drive:
The user can supply the recovery password. If your organization allows users to print or store recovery passwords, the user can type in the 48-digit recovery password that they printed or stored on a USB drive or with your Microsoft Account online. (Saving a recovery password with your Microsoft Account online is only allowed when BitLocker is used on a PC that is not a member of a domain).
A data recovery agent can use their credentials to unlock the drive. If the drive is an operating system drive, the drive must be mounted as a data drive on another computer for the data recovery agent to unlock it.
A domain administrator can obtain the recovery password from AD DS and use it to unlock the drive. Storing recovery passwords in AD DS is recommended to provide a way for IT professionals to be able to obtain recovery passwords for drives in their organization if needed. This method requires that you have enabled this recovery method in the BitLocker Group Policy setting Choose how BitLocker-protected operating system drives can be recovered located at Computer ConfigurationAdministrative TemplatesWindows ComponentsBitLocker Drive EncryptionOperating System Drives in the Local Group Policy Editor. For more information, see BitLocker Group Policy Settings.
What causes BitLocker recovery?
Jul 27, 2016 Microsoft’s BitLocker encryption always forces you to create a recovery key when you set it up. You may have printed that recovery key, written it down, saved it to a file, or stored it online with a Microsoft account. If your BitLocker drive isn’t unlocking normally, the recovery key is your only option. Jul 19, 2016 Be careful with the key–someone that copies the key from your USB drive can use that copy to unlock your BitLocker-encrypted drive. To double-check whether the TPMAndStartupKey protector was added properly, you can run the following command: manage-bde -status (The “Numerical Password” key protector displayed here is your recovery key.).
The following list provides examples of specific events that will cause BitLocker to enter recovery mode when attempting to start the operating system drive:
Device Lockout feature in Windows 8, Windows RT, Windows 8.1 andWindows RT 8.1. On PCs that use either BitLocker or Device Encryption when an attack is detected the device will immediately reboot and enter into BitLocker recovery mode. To take advantage of this functionality Administrators can set the Interactive logon: Machine account lockout threshold Group Policy setting located in Computer ConfigurationWindows SettingsSecurity SettingsLocal PoliciesSecurity Options in the Local Group Policy Editor, or use the MaxFailedPasswordAttempts policy of Exchange ActiveSync (also configurable through Windows Intune), to limit the number of failed password attempts before the device goes into Device Lockout.
Changing the boot order to boot another drive in advance of the hard drive.
Having the CD or DVD drive before the hard drive in the BIOS boot order and then inserting or removing a CD or DVD.
Failing to boot from a network drive before booting from the hard drive.
Docking or undocking a portable computer. In some instances (depending on the computer manufacturer and the BIOS), the docking condition of the portable computer is part of the system measurement and must be consistent to validate the system status and unlock BitLocker. This means that if a portable computer is connected to its docking station when BitLocker is turned on, then it might also need to be connected to the docking station when it is unlocked. Conversely, if a portable computer is not connected to its docking station when BitLocker is turned on, then it might need to be disconnected from the docking station when it is unlocked.
Changes to the NTFS partition table on the disk including creating, deleting, or resizing a primary partition.
Entering the personal identification number (PIN) incorrectly too many times so that the anti-hammering logic of the TPM is activated. Anti-hammering logic is software or hardware methods that increase the difficulty and cost of a brute force attack on a PIN by not accepting PIN entries until after a certain amount of time has passed.
Turning off the support for reading the USB device in the pre-boot environment from the BIOS or UEFI firmware if you are using USB-based keys instead of a TPM.
Turning off, disabling, deactivating, or clearing the TPM.
Upgrading critical early startup components, such as a BIOS or UEFI firmware upgrade, causing the related boot measurements to change.
Forgetting the PIN when PIN authentication has been enabled.
Updating option ROM firmware.
Upgrading TPM firmware.
Adding or removing hardware; for example, inserting a new card in the computer, including some PCMIA wireless cards.
Removing, inserting, or completely depleting the charge on a smart battery on a portable computer.
Changes to the master boot record on the disk.
Changes to the boot manager on the disk.
Hiding the TPM from the operating system. Some BIOS or UEFI settings can be used to prevent the enumeration of the TPM to the operating system. When implemented, this option can make the TPM hidden from the operating system. When the TPM is hidden, BIOS and UEFI secure startup are disabled, and the TPM does not respond to commands from any software.
Using a different keyboard that does not correctly enter the PIN or whose keyboard map does not match the keyboard map assumed by the pre-boot environment. This can prevent the entry of enhanced PINs.
Modifying the Platform Configuration Registers (PCRs) used by the TPM validation profile. For example, including PCR[1] would result in BitLocker measuring most changes to BIOS settings, causing BitLocker to enter recovery mode even when non-boot critical BIOS settings change.
Note
Some computers have BIOS settings that skip measurements to certain PCRs, such as PCR[2]. Changing this setting in the BIOS would cause BitLocker to enter recovery mode because the PCR measurement will be different.
Moving the BitLocker-protected drive into a new computer.
Upgrading the motherboard to a new one with a new TPM.
Losing the USB flash drive containing the startup key when startup key authentication has been enabled.
Failing the TPM self-test.
Having a BIOS, UEFI firmware, or an option ROM component that is not compliant with the relevant Trusted Computing Group standards for a client computer. For example, a non-compliant implementation may record volatile data (such as time) in the TPM measurements, causing different measurements on each startup and causing BitLocker to start in recovery mode.
Changing the usage authorization for the storage root key of the TPM to a non-zero value.
Note
The BitLocker TPM initialization process sets the usage authorization value to zero, so another user or process must explicitly have changed this value.
Disabling the code integrity check or enabling test signing on Windows Boot Manager (Bootmgr).
Pressing the F8 or F10 key during the boot process.
Adding or removing add-in cards (such as video or network cards), or upgrading firmware on add-in cards.
Using a BIOS hot key during the boot process to change the boot order to something other than the hard drive.
Note
Before you begin recovery, we recommend that you determine what caused recovery. This might help prevent the problem from occurring again in the future. For instance, if you determine that an attacker has modified your computer by obtaining physical access, you can create new security policies for tracking who has physical presence. After the recovery password has been used to recover access to the PC, BitLocker will reseal the encryption key to the current values of the measured components.
For planned scenarios, such as a known hardware or firmware upgrades, you can avoid initiating recovery by temporarily suspending BitLocker protection. Because suspending BitLocker leaves the drive fully encrypted, the administrator can quickly resume BitLocker protection after the planned task has been completed. Using suspend and resume also reseals the encryption key without requiring the entry of the recovery key.
Note
If suspended BitLocker will automatically resume protection when the PC is rebooted, unless a reboot count is specified using the manage-bde command line tool.If software maintenance requires the computer be restarted and you are using two-factor authentication, you can enable BitLocker Network Unlock to provide the secondary authentication factor when the computers do not have an on-premise user to provide the additional authentication method.
Recovery has been described within the context of unplanned or undesired behavior, but you can also cause recovery as an intended production scenario, in order to manage access control. For example, when you redeploy desktop or laptop computers to other departments or employees in your enterprise, you can force BitLocker into recovery before the computer is given to a new user.
Testing recovery
Before you create a thorough BitLocker recovery process, we recommend that you test how the recovery process works for both end users (people who call your helpdesk for the recovery password) and administrators (people who help the end user get the recovery password). The –forcerecovery command of manage-bde is an easy way for you to step through the recovery process before your users encounter a recovery situation.
To force a recovery for the local computer
Click the Start button, type
cmdin the Start Search box, right-click cmd.exe, and then click Run as administrator.At the command prompt, type the following command and then press ENTER:
manage-bde -forcerecovery<Volume>
To force recovery for a remote computer
On the Start screen, type cmd.exe, and then click Run as administrator.
At the command prompt, type the following command and then press ENTER:
manage-bde. -ComputerName<ComputerName>-forcerecovery<Volume>
Note
<ComputerName> represents the name of the remote computer. <Volume> represents the volume on the remote computer that is protected with BitLocker.
Planning your recovery process
When planning the BitLocker recovery process, first consult your organization's current best practices for recovering sensitive information. For example: How does your enterprise handle lost Windows passwords? How does your organization perform smart card PIN resets? You can use these best practices and related resources (people and tools) to help formulate a BitLocker recovery model.
Organizations that rely on BitLocker Drive Encryption and BitLocker To Go to protect data on a large number of computers and removable drives running the Windows 8 or Windows 7 operating systems and Windows to Go should consider using the Microsoft BitLocker Administration and Monitoring (MBAM) Tool version 2.0, which is included in the Microsoft Desktop Optimization Pack (MDOP) for Microsoft Software Assurance. MBAM makes BitLocker implementations easier to deploy and manage and allows administrators to provision and monitor encryption for operating system and fixed drives. MBAM prompts the user before encrypting fixed drives. MBAM also manages recovery keys for fixed and removable drives, making recovery easier to manage. MBAM can be used as part of a Microsoft System Center deployment or as a stand-alone solution. For more information, see Microsoft BitLocker Administration and Monitoring.
After a BitLocker recovery has been initiated, users can use a recovery password to unlock access to encrypted data. You must consider both self-recovery and recovery password retrieval methods for your organization.
When you determine your recovery process, you should:
Become familiar with how you can retrieve the recovery password. See:
Determine a series of steps for post-recovery, including analyzing why the recovery occurred and resetting the recovery password. See:
Self-recovery
In some cases, users might have the recovery password in a printout or a USB flash drive and can perform self-recovery. We recommend that your organization create a policy for self-recovery. If self-recovery includes using a password or recovery key stored on a USB flash drive, the users should be warned not to store the USB flash drive in the same place as the PC, especially during travel, for example if both the PC and the recovery items are in the same bag it would be very easy for access to be gained to the PC by an unauthorized user. Another policy to consider is having users contact the Helpdesk before or after performing self-recovery so that the root cause can be identified.
Recovery password retrieval
If the user does not have a recovery password in a printout or on a USB flash drive, the user will need to be able to retrieve the recovery password from an online source. If the PC is a member of a domain the recovery password can be backed up to AD DS. However, this does not happen by default, you must have configured the appropriate Group Policy settings before BitLocker was enabled on the PC. BitLocker Group Policy settings can be found in the Local Group Policy Editor or the Group Policy Management Console (GPMC) under Computer ConfigurationAdministrative TemplatesWindows ComponentsBitLocker Drive Encryption. The following policy settings define the recovery methods that can be used to restore access to a BitLocker-protected drive if an authentication method fails or is unable to be used.
Choose how BitLocker-protected operating system drives can be recovered
Choose how BitLocker-protected fixed drives can be recovered
Choose how BitLocker-protected removable drives can be recovered
In each of these policies select Save BitLocker recovery information to Active Directory Domain Services and then choose which BitLocker recovery information to store in Active Directory Domain Services (AD DS). Select the Do not enable BitLocker until recovery information is stored in AD DS check box if you want to prevent users from enabling BitLocker unless the computer is connected to the domain and the backup of BitLocker recovery information for the drive to AD DS succeeds.
Note
If the PCs are part of a workgroup, users should be advised to save their BitLocker recovery password with their Microsoft Account online. Having an online copy of your BitLocker recovery password is recommended to help ensure that you do not lose access to your data in the event that recovery is required.
The BitLocker Recovery Password Viewer for Active Directory Users and Computers tool allows domain administrators to view BitLocker recovery passwords for specific computer objects in Active Directory.
You can use the following list as a template for creating your own recovery process for recovery password retrieval. This sample process uses the BitLocker Recovery Password Viewer for Active Directory Users and Computers tool.
Record the name of the user's computer
You can use the name of the user's computer to locate the recovery password in AD DS. If the user does not know the name of the computer, ask the user to read the first word of the Drive Label in the BitLocker Drive Encryption Password Entry user interface. This is the computer name when BitLocker was enabled and is probably the current name of the computer.
Verify the user's identity
You should verify that the person that is asking for the recovery password is truly the authorized user of that computer. You may also wish to verify that the computer with the name the user provided belongs to the user.
Locate the recovery password in AD DS
Locate the Computer object with the matching name in AD DS. Because Computer object names are listed in the AD DS global catalog, you should be able to locate the object even if you have a multi-domain forest.
Multiple recovery passwords
If multiple recovery passwords are stored under a computer object in AD DS, the name of the BitLocker recovery information object includes the date that the password was created.
If at any time you are unsure what password to provide, or if you think you might be providing the incorrect password, ask the user to read the eight character password ID that is displayed in the recovery console.
Since the password ID is a unique value that is associated with each recovery password stored in AD DS, running a query using this ID will find the correct password to unlock the encrypted volume.
Gather information to determine why recovery occurred
Before you give the user the recovery password, you should gather any information that will help determine why the recovery was needed, in order to analyze the root cause during the post-recovery analysis. For more information about post-recovery analysis, see Post-recovery analysis.
Give the user the recovery password
Because the recovery password is 48 digits long the user may need to record the password by writing it down or typing it on a different computer. If you are using MBAM, the recovery password will be regenerated after it is recovered from the MBAM database to avoid the security risks associated with an uncontrolled password.
Note
Because the 48-digit recovery password is long and contains a combination of digits, the user might mishear or mistype the password. The boot-time recovery console uses built-in checksum numbers to detect input errors in each 6-digit block of the 48-digit recovery password, and offers the user the opportunity to correct such errors.
Post-recovery analysis
When a volume is unlocked using a recovery password, an event is written to the event log and the platform validation measurements are reset in the TPM to match the current configuration. Unlocking the volume means that the encryption key has been released and is ready for on-the-fly encryption when data is written to the volume, and on-the-fly decryption when data is read from the volume. Office 2007 product key generator online. After the volume is unlocked, BitLocker behaves the same way, regardless of how the access was granted.
If you notice that a computer is having repeated recovery password unlocks, you might want to have an administrator can perform post-recovery analysis to determine the root cause of the recovery and refresh BitLocker platform validation so that the user no longer needs to enter a recovery password each time that the computer starts up. See:
Determine the root cause of the recovery
If a user needed to recover the drive, it is important to determine the root cause that initiated the recovery as soon as possible. Properly analyzing the state of the computer and detecting tampering may reveal threats that have broader implications for enterprise security.
While an administrator can remotely investigate the cause of recovery in some cases, the end user might need to bring the computer that contains the recovered drive on site to analyze the root cause further.
Review and answer the following questions for your organization:
What BitLocker protection mode is in effect (TPM, TPM + PIN, TPM + startup key, startup key only)? Which PCR profile is in use on the PC?
Did the user merely forget the PIN or lose the startup key? If a token was lost, where might the token be?
If TPM mode was in effect, was recovery caused by a boot file change?
If recovery was caused by a boot file change, is this due to an intended user action (for example, BIOS upgrade), or to malicious software?
When was the user last able to start the computer successfully, and what might have happened to the computer since then?
Might the user have encountered malicious software or left the computer unattended since the last successful startup?
To help you answer these questions, use the BitLocker command-line tool to view the current configuration and protection mode (for example, manage-bde -status). Scan the event log to find events that help indicate why recovery was initiated (for example, if boot file change occurred). Both of these capabilities can be performed remotely.
Resolve the root cause
After you have identified what caused recovery, you can reset BitLocker protection and avoid recovery on every startup.
The details of this reset can vary according to the root cause of the recovery. If you cannot determine the root cause, or if malicious software or a rootkit might have infected the computer, Helpdesk should apply best-practice virus policies to react appropriately.
Note
You can perform a BitLocker validation profile reset by suspending and resuming BitLocker.
Unknown PIN
If a user has forgotten the PIN, you must reset the PIN while you are logged on to the computer in order to prevent BitLocker from initiating recovery each time the computer is restarted.
To prevent continued recovery due to an unknown PIN
Unlock the computer using the recovery password.
Reset the PIN:
Right-click the drive and then click Change PIN/ubuntu-generate-ssh-key-for-root.html.
In the BitLocker Drive Encryption dialog, click Reset a forgotten PIN. If you are not logged in with an administrator account you must provide administrative credentials at this time.
In the PIN reset dialog, provide and confirm the new PIN to use and then click Finish.
You will use the new PIN the next time you unlock the drive.
Lost startup key
If you have lost the USB flash drive that contains the startup key, then you must unlock the drive by using the recovery key and then create a new startup key.
To prevent continued recovery due to a lost startup key
Log on as an administrator to the computer that has the lost startup key.
From the Start screen open Manage BitLocker
Click Duplicate start up key, insert the clean USB drive on which you are going to write the key and then click Save.
Changes to boot files
This error might occur if you updated the firmware. As a best practice you should suspend BitLocker before making changes the firmware and then resume protection after the update has completed. This prevents the computer from going into recovery mode. However if changes were made when BitLocker protection was on you can simply log on to the computer using the recovery password and the platform validation profile will be updated so that recovery will not occur the next time.
Windows RE and BitLocker
Windows Recovery Environment (RE) can be used to recover access to a drive protected by BitLocker or by Device Encryption. If a PC is unable to boot after two failures, Startup Repair will automatically start. When Startup Repair is launched automatically due to boot failures, it will only execute operating system and driver file repairs, provided that the boot logs or any available crash dump point to a specific corrupted file. In Windows 8.1 on systems that include firmware to support specific TPM measurements for PCR[7] the TPM can validate that Windows RE is a trusted operating environment and will unlock any BitLocker-protected drives if Windows RE has not been modified. If the Windows RE environment has been modified, for example the TPM has been disabled, the drives will stay locked until the BitLocker recovery key is provided. If Startup Repair is not able to be run automatically from the PC and instead Windows RE is manually started from a repair disk, the BitLocker recovery key must be provided to unlock the BitLocker–protected drives.
Using additional recovery information
Besides the 48-digit BitLocker recovery password, other types of recovery information are stored in Active Directory. This section describes how this additional information can be used.
BitLocker key package
If the recovery methods discussed earlier in this document do not unlock the volume, you can use the BitLocker Repair tool to decrypt the volume at the block level. The tool uses the BitLocker key package to help recover encrypted data from severely damaged drives. You can then use this recovered data to salvage encrypted data, even after the correct recovery password has failed to unlock the damaged volume. We recommend that you still save the recovery password. A key package cannot be used without the corresponding recovery password.
Note
You must use the BitLocker Repair tool repair-bde to use the BitLocker key package.
The BitLocker key package is not saved by default. To save the package along with the recovery password in AD DS you must select the Backup recovery password and key package option in the Group Policy settings that control the recovery method. You can also export the key package from a working volume. For more details on how to export key packages, see Retrieving the BitLocker key package.
Resetting recovery passwords
You should invalidate a recovery password after it has been provided and used. It should also be done when you intentionally want to invalidate an existing recovery password for any reason.
You can reset the recovery password in two ways:
Use manage-bde You can use manage-bde to remove the old recovery password and add a new recovery password. The procedure identifies the command and the syntax for this method.
Run a script You can run a script to reset the password without decrypting the volume. The sample script in the procedure illustrates this functionality. The sample script creates a new recovery password and invalidates all other passwords.
To reset a recovery password using manage-bde
Remove the previous recovery password
Add the new recovery password
Get the ID of the new recovery password. From the screen copy the ID of the recovery password.
Backup the new recovery password to AD DS
Warning
You must include the braces in the ID string.
To run the sample recovery password script
Save the following sample script in a VBScript file. For example: ResetPassword.vbs.
At the command prompt, type a command similar to the following:
cscript ResetPassword.vbs
Important
Generate Bitlocker Recovery Key
This sample script is configured to work only for the C volume. You must customize the script to match the volume where you want to test password reset.
Note
To manage a remote computer, you can specify the remote computer name rather than the local computer name.
You can use the following sample script to create a VBScript file to reset the recovery passwords.
Retrieving the BitLocker key package
You can use two methods to retrieve the key package, as described in Using additional recovery information:
Export a previously-saved key package from AD DS. You must have Read access to BitLocker recovery passwords that are stored in AD DS.
Export a new key package from an unlocked, BitLocker-protected volume. You must have local administrator access to the working volume, before any damage has occurred.
The following sample script exports all previously-saved key packages from AD DS.
Generate Bitlocker Recovery Key From Password Windows 7
To run the sample key package retrieval script
Save the following sample script in a VBScript file. For example: GetBitLockerKeyPackageADDS.vbs.
At the command prompt, type a command similar to the following:
cscript GetBitLockerKeyPackageADDS.vbs -?
You can use the following sample script to create a VBScript file to retrieve the BitLocker key package from AD DS.
The following sample script exports a new key package from an unlocked, encrypted volume.
To run this script, start by saving the code into a VBS file (for example, GetBitLockerKeyPackage.vbs). Then, open an administrator command prompt and use “cscript” to run the saved file (for example, type 'cscript GetBitLockerKeyPackage.vbs -?').
See also
-->Applies to
- Windows 10
How can I authenticate or unlock my removable data drive?
You can unlock removable data drives by using a password, a smart card, or you can configure a SID protector to unlock a drive by using your domain credentials. After you've started encryption, the drive can also be automatically unlocked on a specific computer for a specific user account. System administrators can configure which options are available for users, as well as password complexity and minimum length requirements. To unlock by using a SID protector, use Manage-bde:
Manage-bde -protectors -add e: -sid domainusername
What is the difference between a recovery password, recovery key, PIN, enhanced PIN, and startup key?
For tables that list and describe elements such as a recovery password, recovery key, and PIN, see BitLocker key protectors and BitLocker authentication methods.
How can the recovery password and recovery key be stored?
How To Find My Bitlocker Recovery Key
The recovery password and recovery key for an operating system drive or a fixed data drive can be saved to a folder, saved to one or more USB devices, saved to your Microsoft Account, or printed.
For removable data drives, the recovery password and recovery key can be saved to a folder, saved to your Microsoft Account, or printed. By default, you cannot store a recovery key for a removable drive on a removable drive.
A domain administrator can additionally configure Group Policy to automatically generate recovery passwords and store them in Active Directory Domain Services (AD DS) for any BitLocker-protected drive.
Is it possible to add an additional method of authentication without decrypting the drive if I only have the TPM authentication method enabled?
You can use the Manage-bde.exe command-line tool to replace your TPM-only authentication mode with a multifactor authentication mode. For example, if BitLocker is enabled with TPM authentication only and you want to add PIN authentication, use the following commands from an elevated command prompt, replacing 4-20 digit numeric PIN with the numeric PIN you want to use:
manage-bde –protectors –delete %systemdrive% -type tpm
manage-bde –protectors –add %systemdrive% -tpmandpin 4-20 digit numeric PIN
When should an additional method of authentication be considered?
New hardware that meets Windows Hardware Compatibility Program requirements make a PIN less critical as a mitigation, and having a TPM-only protector is likely sufficient when combined with policies like device lockout. For example, Surface Pro and Surface Book do not have external DMA ports to attack.For older hardware, where a PIN may be needed, it’s recommended to enable enhanced PINs that allow non-numeric characters such as letters and punctuation marks, and to set the PIN length based on your risk tolerance and the hardware anti-hammering capabilities available to the TPMs in your computers.
If I lose my recovery information, will the BitLocker-protected data be unrecoverable?
BitLocker is designed to make the encrypted drive unrecoverable without the required authentication. When in recovery mode, the user needs the recovery password or recovery key to unlock the encrypted drive.
Important
Store the recovery information in AD DS, along with your Microsoft Account, or another safe location.
Can the USB flash drive that is used as the startup key also be used to store the recovery key?
While this is technically possible, it is not a best practice to use one USB flash drive to store both keys. If the USB flash drive that contains your startup key is lost or stolen, you also lose access to your recovery key. In addition, inserting this key would cause your computer to automatically boot from the recovery key even if TPM-measured files have changed, which circumvents the TPM's system integrity check.
Can I save the startup key on multiple USB flash drives?
Yes, you can save a computer's startup key on multiple USB flash drives. Right-clicking a BitLocker-protected drive and selecting Manage BitLocker will provide you the options to duplicate the recovery keys as needed.
Can I save multiple (different) startup keys on the same USB flash drive?
Yes, you can save BitLocker startup keys for different computers on the same USB flash drive.
Can I generate multiple (different) startup keys for the same computer?
You can generate different startup keys for the same computer through scripting. However, for computers that have a TPM, creating different startup keys prevents BitLocker from using the TPM's system integrity check.
Can I generate multiple PIN combinations?
You cannot generate multiple PIN combinations.
What encryption keys are used in BitLocker? How do they work together?
Raw data is encrypted with the full volume encryption key, which is then encrypted with the volume master key. The volume master key is in turn encrypted by one of several possible methods depending on your authentication (that is, key protectors or TPM) and recovery scenarios.
Where are the encryption keys stored?
The full volume encryption key is encrypted by the volume master key and stored in the encrypted drive. The volume master key is encrypted by the appropriate key protector and stored in the encrypted drive. If BitLocker has been suspended, the clear key that is used to encrypt the volume master key is also stored in the encrypted drive, along with the encrypted volume master key.
This storage process ensures that the volume master key is never stored unencrypted and is protected unless you disable BitLocker. The keys are also saved to two additional locations on the drive for redundancy. The keys can be read and processed by the boot manager.
Generate Bitlocker Recovery Key From Password Key
Why do I have to use the function keys to enter the PIN or the 48-character recovery password?
The F1 through F10 keys are universally mapped scan codes available in the pre-boot environment on all computers and in all languages. The numeric keys 0 through 9 are not usable in the pre-boot environment on all keyboards.
When using an enhanced PIN, users should run the optional system check during the BitLocker setup process to ensure that the PIN can be entered correctly in the pre-boot environment.
How does BitLocker help prevent an attacker from discovering the PIN that unlocks my operating system drive?
It is possible that a personal identification number (PIN) can be discovered by an attacker performing a brute force attack. A brute force attack occurs when an attacker uses an automated tool to try different PIN combinations until the correct one is discovered. For BitLocker-protected computers, this type of attack, also known as a dictionary attack, requires that the attacker have physical access to the computer.
The TPM has the built-in ability to detect and react to these types of attacks. Because different manufacturers' TPMs may support different PIN and attack mitigations, contact your TPM's manufacturer to determine how your computer's TPM mitigates PIN brute force attacks.After you have determined your TPM's manufacturer, contact the manufacturer to gather the TPM's vendor-specific information. Most manufacturers use the PIN authentication failure count to exponentially increase lockout time to the PIN interface. However, each manufacturer has different policies regarding when and how the failure counter is decreased or reset.
How can I determine the manufacturer of my TPM?
You can determine your TPM manufacturer in Windows Defender Security Center > Device Security > Security processor details.
How can I evaluate a TPM's dictionary attack mitigation mechanism?
The following questions can assist you when asking a TPM manufacturer about the design of a dictionary attack mitigation mechanism:
- How many failed authorization attempts can occur before lockout?
- What is the algorithm for determining the duration of a lockout based on the number of failed attempts and any other relevant parameters?
- What actions can cause the failure count and lockout duration to be decreased or reset?
Can PIN length and complexity be managed with Group Policy?
Yes and No. You can configure the minimum personal identification number (PIN) length by using the Configure minimum PIN length for startup Group Policy setting and allow the use of alphanumeric PINs by enabling the Allow enhanced PINs for startup Group Policy setting. However, you cannot require PIN complexity by Group Policy.
For more info, see BitLocker Group Policy settings.