Information
This policy setting allows you to specify whether a password is required to unlock BitLocker-protected removable data drives.
Note: This setting is enforced when turning on BitLocker, not when unlocking a drive.
BitLocker will allow unlocking a drive with any of the protectors available on the drive.
The recommended state for this setting is: 'Disabled'.
Rationale:
Using a dictionary-style attack, passwords can be guessed or discovered by repeatedly attempting to unlock a drive.
Since this type of BitLocker password does not include anti-dictionary attack protections provided by a TPM, for example, there is no mechanism to slow down use of rapid brute-force attacks against them.
Solution
To establish the recommended configuration via GP, set the following UI path to 'Disabled':
Computer Configuration\Policies\Administrative Templates\Windows Components\BitLocker Drive Encryption\Removable Data Drives\Configure use of passwords for removable data drives
Note: This Group Policy path may not exist by default.
It is provided by the Group Policy template 'VolumeEncryption.admx/adml' that is included with the Microsoft Windows 7 & Server 2008 R2 Administrative Templates (or newer).
Impact:
The password option will not be available when configuring BitLocker for removable drives.