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ProtectKeyWithTPMAndPINAndStartupKey method of the Win32_EncryptableVolume class

The ProtectKeyWithTPMAndPINAndStartupKey method of the Win32_EncryptableVolume class secures the volume's encryption key by using the Trusted Platform Module (TPM) on the computer, if available, enhanced by both a user-specified personal identification number (PIN) and by an external key that must be presented to the computer at startup.

Three factors of authentication are needed to unlock the encrypted contents of the volume:

  1. Validation by the TPM
  2. Input of a 4 to 20 digit PIN or, if the "Allow enhanced PINs for startup" group policy is enabled, 4 to 20 letters, symbols, spaces, or numbers
  3. Input of a USB memory device that contains the external key

Use the SaveExternalKeyToFile method to save this external key to a file on a USB memory device for usage as a startup key. This method applies only on the operating system volume. A key protector of type "TPM And PIN And Startup Key" is created.

Syntax


uint32 ProtectKeyWithTPMAndPINAndStartupKey(
  [in, optional]  string FriendlyName,
  [in, optional]  uint8 PlatformValidationProfile,
  [in]            string PIN,
  [in, optional]  uint8 ExternalKey[],
  [out]           string VolumeKeyProtectorID
);

Parameters

FriendlyName [in, optional]

Type: string

A string that labels this key protector. If this parameter is not specified, a blank value is used.

PlatformValidationProfile [in, optional]

Type: uint8

An array of integers that specifies how the computer's TPM secures the volume's encryption key. A platform validation profile consists of a set of Platform Configuration Register (PCR) indices ranging from 0 to 23, inclusive. Repeat values in the parameter are ignored. Each PCR index is associated with services that run when the operating system starts. Each time the computer starts, the TPM will check that the services you specified in the platform validation profile have not changed. If any of these services change while BitLocker protection remains on, the TPM will not release the encryption key to unlock the volume and the computer will enter into recovery mode.

If this parameter is not specified, the default indices of 0, 2, 4, 5, 8, 9, 10, and 11 are used. The default platform validation profile secures the encryption key against changes to the Core Root of Trust of Measurement (CRTM), BIOS, and Platform Extensions (PCR 0), Option ROM Code (PCR 2), Master Boot Record (MBR) Code (PCR 4), Master Boot Record (MBR) Partition Table (PCR 5), the NTFS Boot Sector (PCR 8), the NTFS Boot Block (PCR 9), the Boot Manager (PCR 10), and the BitLocker Access Control (PCR 11). Unified Extensible Firmware Interface (UEFI)–based computers do not use PCR 5 by default.

The default platform validation profile is recommended. For additional protection against early startup configuration changes, use a profile of PCRs 0, 1, 2, 3, 4, 5, 8, 9, 10, 11.

Changing the default profile affects the security and manageability of your computer. The sensitivity of BitLocker to platform modifications (malicious or authorized) is increased or decreased depending upon the inclusion or exclusion, respectively, of the PCRs. For BitLocker protection to be enabled, the platform validation profile must include PCR 11.

ValueMeaning
0

Core Root of Trust of Measurement (CRTM), BIOS, and Platform Extensions

1

Platform and Motherboard Configuration and Data

2

Option ROM Code

3

Option ROM Configuration and Data

4

Master Boot Record (MBR) Code

5

Master Boot Record (MBR) Partition Table

6

State Transition and Wake Events

7

Computer Manufacturer-Specific

8

NTFS Boot Sector

9

NTFS Boot Block

10

Boot Manager

11

BitLocker Access Control

12

Defined for use by the static operating system

13

Defined for use by the static operating system

14

Defined for use by the static operating system

15

Defined for use by the static operating system

16

Used for debugging

17

Dynamic CRTM

18

Platform defined

19

Used by a trusted operating system

20

Used by a trusted operating system

21

Used by a trusted operating system

22

Used by a trusted operating system

23

Application support

 

PIN [in]

Type: string

Contains a 4 to 20-digit personal identification number (PIN) or, if the "Allow enhanced PINs for startup" group policy is enabled, 4 and 20 letters, symbols, spaces, or numbers. This string must be provided to the computer at startup.

ExternalKey [in, optional]

Type: uint8[]

An array of bytes that specifies the 256-bit external key used to unlock the volume when the computer starts. Leave this parameter blank to randomly generate the external key. Use the GetKeyProtectorExternalKey method to obtain the randomly generated key.

VolumeKeyProtectorID [out]

Type: string

The updated unique string identifier used to manage an encrypted volume key protector.

If the drive supports hardware encryption and BitLocker has not taken band ownership, the ID string is set to "BitLocker" and the key protector is written to per band metadata.

Return value

Type: uint32

This method returns one of the following codes or another error code if it fails.

Return code/valueDescription
S_OK
0 (0x0)

The method was successful.

E_INVALIDARG
2147942487 (0x80070057)

The PlatformValidationProfile parameter is provided, but its values are not within the known range, or it does not match the Group Policy setting that is currently in effect.

The ExternalKey parameter is provided but it is not an array of size 32.

FVE_E_BOOTABLE_CDDVD
2150694960 (0x80310030)

A bootable CD/DVD is found in this computer. Remove the CD/DVD and restart the computer.

FVE_E_FOREIGN_VOLUME
2150694947 (0x80310023)

The TPM cannot secure the volume's encryption key because the volume does not contain the currently running operating system.

FVE_E_INVALID_PIN_CHARS
2150695066 (0x8031009A)

The NewPIN parameter contains characters that are not valid. When the "Allow enhanced PINs for startup" Group Policy is disabled, only numbers are supported.

FVE_E_LOCKED_VOLUME
2150694912 (0x80310000)

The volume is locked.

FVE_E_POLICY_INVALID_PIN_LENGTH
2150695016 (0x80310068)

The NewPIN parameter supplied is either longer than 20 characters, shorter than 4 characters, or shorter than the minimum length specified by Group Policy.

FVE_E_PROTECTOR_EXISTS
2150694961 (0x80310031)

A key protector of this type already exists.

TBS_E_SERVICE_NOT_RUNNING
2150121480 (0x80284008)

No compatible TPM is found on this computer.

 

Remarks

At most one key protector of type "TPM And PIN And Startup Key" can exist for a volume at any time. If you want to change the display name or the platform validation profile used by an existing "TPM And PIN And Startup Key" key protector, you must first remove the existing key protector and then call ProtectKeyWithTPMAndPINAndStartupKey to create a new one.

Additional key protectors should be specified to unlock the volume in recovery scenarios where access to the volume's encryption key cannot be obtained; for example, when the TPM cannot successfully validate against the platform validation profile or when the PIN is lost. Use ProtectKeyWithExternalKey or ProtectKeyWithNumericalPassword to create one or more key protectors for recovering an otherwise locked volume.

While it is possible to have both a key protector of the type "TPM" and another of the type "TPM And PIN And Startup Key", the presence of the "TPM" key protector type negates the effects of other TPM-based key protectors.

Managed Object Format (MOF) files contain the definitions for Windows Management Instrumentation (WMI) classes. MOF files are not installed as part of the Windows SDK. They are installed on the server when you add the associated role by using the Server Manager. For more information about MOF files, see Managed Object Format (MOF).

Requirements

Minimum supported client

Windows Vista Enterprise with SP1, Windows Vista Ultimate with SP1 [desktop apps only]

Minimum supported server

Windows Server 2008 [desktop apps only]

Namespace

\\.\root\CIMV2\Security\MicrosoftVolumeEncryption

MOF

Win32_encryptablevolume.mof

See also

Win32_EncryptableVolume

 

 

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