Difference between revisions of "BitLocker Disk Encryption"

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(Textual changes and additions. Removed reference to FreeOTFE does not seem to provide BitLocker support.)
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'''BitLocker Disk Encryption''' is a [[Microsoft]] [[Full Volume Encryption]] solution first included with the Enterprise and Ultimate editions of [[Windows|Windows Vista]]. It is also present in [[Windows 7]] along with a system for encrypting [[USB]] devices called [[BitLocker To Go]].
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'''BitLocker Disk Encryption''' (BDE) is a [[Microsoft]] [[Full Volume Encryption]] solution first included with the Enterprise and Ultimate editions of [[Windows|Windows Vista]]. It is also present in [[Windows 7]] along with a system for encrypting removable storage media devices, like [[USB]], which is called [[BitLocker To Go]].
  
Drives protected with BitLocker will have a different signature than the standard [[NTFS]] header. Instead, they have in their first sector: <tt>EB 52 90 2D 46 56 45 2D 46 53 2D</tt> or, in ASCII, <tt>eR -FVE-FS-</tt>
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Volumes encrypted with BitLocker will have a different signature than the standard [[NTFS]] header. Instead, they have in their volume header (first sector): <tt>2D 46 56 45 2D 46 53 2D</tt> or, in ASCII, <tt>-FVE-FS-</tt>.
  
The actual data on a drive is protected with either 128-bit or 256-bit [[AES]] and optionally diffused using an algorithm called Elephant. The key used to do that encryption, the Full Volume Encryption Key (FVEK), is stored in the BitLocker metadata on the protected volume. The FVEK is encrypted using another key, the Volume Master Key (VMK). Several copies of the VMK are also stored in the metadata. Each copy of the VMK is encrypted using another key. The nature of those keys and the algorithm used depends on how the system is configured.
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Volumes encrypted with BitLocker To Go will have a hybrid encrypted volume, meaning that part of the volume is unencrypted and contains applications to unlock the volume and the other part of the volume is encypted. These volumes can be identifier by the BitLocker GUID/UUID: 4967d63b-2e29-4ad8-8399-f6a339e3d00.
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The actual data on the encrypted volume is protected with either 128-bit or 256-bit [[AES]] and optionally diffused using an algorithm called Elephant. The key used to do the encryption, the Full Volume Encryption Key (FVEK) and/or TWEAK key, is stored in the BitLocker metadata on the protected volume. The FVEK and/or TWEAK keys are encrypted using another key, namely the Volume Master Key (VMK). Several copies of the VMK are also stored in the metadata. Each copy of the VMK is encrypted using another key, also know as key-protector keys. Several key-protectors are:
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* TPM (Trusted Platform Module)
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* recovery password
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* start-up key
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* clear key; this key-protector provides no protection
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* user password
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BitLocker has support for partial encrypted volumes.
  
 
== See Also ==
 
== See Also ==
* [[FreeOTFE]]
 
 
* [[BitLocker To Go]]
 
* [[BitLocker To Go]]
 
* [[Defeating Whole Disk Encryption]]
 
* [[Defeating Whole Disk Encryption]]
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== External Links ==
 
== External Links ==
  
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* [http://www.nvlabs.in/archives/1-NVbit-Accessing-Bitlocker-volumes-from-linux.html NVbit : Accessing Bitlocker volumes from linux], 2008
 
* Jesse D. Kornblum, [http://jessekornblum.com/publications/di09.html Implementing BitLocker for Forensic Analysis], ''Digital Investigation'', 2009
 
* Jesse D. Kornblum, [http://jessekornblum.com/publications/di09.html Implementing BitLocker for Forensic Analysis], ''Digital Investigation'', 2009
 
* [http://en.wikipedia.org/wiki/BitLocker_Drive_Encryption Wikipedia entry on BitLocker]
 
* [http://en.wikipedia.org/wiki/BitLocker_Drive_Encryption Wikipedia entry on BitLocker]
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* [http://www.microsoft.com/downloads/details.aspx?FamilyID=131dae03-39ae-48be-a8d6-8b0034c92555&DisplayLang=en Microsoft Description of the Encryption Algorithm]
 
* [http://www.microsoft.com/downloads/details.aspx?FamilyID=131dae03-39ae-48be-a8d6-8b0034c92555&DisplayLang=en Microsoft Description of the Encryption Algorithm]
 
* [http://secude.com/htm/801/en/White_Paper%3A_Cold_Boot_Attacks.htm Cold Boot Attacks, Full Disk Encryption, and BitLocker]
 
* [http://secude.com/htm/801/en/White_Paper%3A_Cold_Boot_Attacks.htm Cold Boot Attacks, Full Disk Encryption, and BitLocker]
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* [http://code.google.com/p/libbde/ Project to read BitLocker encrypted volumes]
  
 
[[Category:Disk encryption]]
 
[[Category:Disk encryption]]
 
[[Category:Windows]]
 
[[Category:Windows]]

Revision as of 11:18, 25 September 2011

BitLocker Disk Encryption (BDE) is a Microsoft Full Volume Encryption solution first included with the Enterprise and Ultimate editions of Windows Vista. It is also present in Windows 7 along with a system for encrypting removable storage media devices, like USB, which is called BitLocker To Go.

Volumes encrypted with BitLocker will have a different signature than the standard NTFS header. Instead, they have in their volume header (first sector): 2D 46 56 45 2D 46 53 2D or, in ASCII, -FVE-FS-.

Volumes encrypted with BitLocker To Go will have a hybrid encrypted volume, meaning that part of the volume is unencrypted and contains applications to unlock the volume and the other part of the volume is encypted. These volumes can be identifier by the BitLocker GUID/UUID: 4967d63b-2e29-4ad8-8399-f6a339e3d00.

The actual data on the encrypted volume is protected with either 128-bit or 256-bit AES and optionally diffused using an algorithm called Elephant. The key used to do the encryption, the Full Volume Encryption Key (FVEK) and/or TWEAK key, is stored in the BitLocker metadata on the protected volume. The FVEK and/or TWEAK keys are encrypted using another key, namely the Volume Master Key (VMK). Several copies of the VMK are also stored in the metadata. Each copy of the VMK is encrypted using another key, also know as key-protector keys. Several key-protectors are:

  • TPM (Trusted Platform Module)
  • recovery password
  • start-up key
  • clear key; this key-protector provides no protection
  • user password

BitLocker has support for partial encrypted volumes.

See Also

External Links