Difference between pages "FAT" and "BitLocker Disk Encryption"

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The FAT allocation system is primarly concerned with a descrete method of organizing files. In order to protect the file system, two copies are stored: FAT1 and FAT2. With two copies available redundancy is achieved in case one fails. The partition Boot Sector stores information critical to the file system. This information includes the number of sectors, and number of clustors, the number of sectors per cluster and more. When a computer user wants to read any type of file, the FAT file system also reassembles each piece of the file into one complete unit for viewing.
+
'''BitLocker Disk Encryption''' (BDE) is [[Full Volume Encryption]] solution by [[Microsoft]] first included with the Enterprise and Ultimate editions of [[Windows|Windows Vista]]. It is also present in [[Windows|Windows 7]] along with a system for encrypting removable storage media devices, like [[USB]], which is called BitLocker To Go. Unlike previous versions of BitLocker, BitLocker To Go allows the user to protect volumes with a password or smart card.
The Root Folder contains a small piece of information for each file and directory in the system. Unlike other files in the system the Root Folder has a fixed size.
+
  
* FAT Partition Boot Sector
+
== BitLocker ==
* FAT File System
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BitLocker encrypts data with either 128-bit or 256-bit [[AES]] and optionally using a diffuser 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 key. Some of the key-protectors are:
* FAT Root Folder
+
* TPM (Trusted Platform Module)
* FAT Folder Structure
+
* Smart card
 +
* recovery password
 +
* start-up key
 +
* clear key; this key-protector provides no protection
 +
* user password
  
[[Image:Recover-FAT-volume-structur.jpg]]
+
BitLocker has support for partial encrypted volumes.
  
'''History'''
+
== How to detect ==
 +
Volumes encrypted with BitLocker will have a different signature than the standard [[NTFS]] header.
  
----
+
A BitLocker encrypted volume starts with the "-FVE-FS-" signature.
  
 +
A hexdump of the start of the volume should look similar to:
 +
<pre>
 +
00000000  eb 58 90 2d 46 56 45 2d  46 53 2d 00 02 08 00 00  |.X.-FVE-FS-.....|
 +
00000010  00 00 00 00 00 f8 00 00  3f 00 ff 00 00 00 00 00  |........?.......|
 +
00000020  00 00 00 00 e0 1f 00 00  00 00 00 00 00 00 00 00  |................|
 +
00000030  01 00 06 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 +
00000040  80 00 29 00 00 00 00 4e  4f 20 4e 41 4d 45 20 20  |..)....NO NAME  |
 +
00000050  20 20 46 41 54 33 32 20  20 20 33 c9 8e d1 bc f4  |  FAT32  3.....|
 +
</pre>
  
Originally developed by Bill Gates in 1976 as a way to store data on floppy disks for a version of Basic, the file allocation table system was quickly incorporated into an early version of Tim Patterson's (of Seattle Computer Products fame) operating system, QDOS ("Quick and Dirty Operating System"). Gates later bought the rights to QDOS and released it under Microsoft as PC-DOS and later, MS-DOS.
+
These volumes can also be identified by the BitLocker GUID/UUID: 4967d63b-2e29-4ad8-8399-f6a339e3d00 or 4967d63b-2e29-4ad8-8399-f6a339e3d01 for BitLocker ToGo.
  
----
+
<pre>
 +
000000a0  3b d6 67 49 29 2e d8 4a  83 99 f6 a3 39 e3 d0 01  |;.gI)..J....9...|
 +
</pre>
  
'''FAT12'''
+
== BitLocker To Go ==
<br />
+
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 encrypted. The "discovery drive" volume contains BitLocker To Go Reader to read from encrypted volumes on versions of Microsoft [[Windows]] without BitLocker support.
*  FAT12 is the oldest type of FAT that uses a 12 bit file allocation table entry. 
+
*  FAT12 can hold a max of 4,086 clusters (which is 2<sup>12</sup> clusters minus a few values that are reserved for values used in  the FAT). 
+
*  It is used for floppy disks and hard drive partitions that are smaller than 16 MB.
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*  All 1.4 MB 3.5 inch floppy disks are formatted using FAT12.
+
<br />
+
  
----
+
== manage-bde ==
+
To view the BitLocker Drive Encryption (BDE) status on a running Windows system:
'''FAT32''':
+
<pre>
FAT32 is the enhanced version of the FAT system implemented beginning with Windows 95 OSR2, Windows 98, and Windows Me.
+
manage-bde.exe -status
Features include:
+
</pre>
*  Drives of up to 2 terabytes are supported (Windows 2000 only supports up to 32 gigabytes)
+
*  Since FAT32 uses smaller clusters (of 4 kilobytes each), it uses hard drive space more efficiently. This is a 10 to 15 percent improvement over FAT or FAT16.
+
*  The limitations of FAT or FAT 16 on the number of root folder entries have been eliminated. In FAT32, the root folder is an ordinary cluster chain, and can be located anywhere on the drive.
+
*  File allocation mirroring can be disabled in FAT32. This allows a different copy of the file allocation table then the default to be active.
+
  
Currently the FAT file system has become the ubiquitous format that is used for interchange of media between computers. Since the advent of less expensive, removable flash memory, the FAT file system has become the format that is used between digital devices. Some items in which you might find the FAT file format are:
+
To obtain the recovery password for volume C:
 +
<pre>
 +
manage-bde.exe -protectors -get C: -Type recoverypassword
 +
</pre>
  
* Thumb drives
+
Or just obtain the all “protectors” for volume C:
* Portable digital still/video cameras
+
<pre>
* Portable digital audio and video players
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manage-bde.exe -protectors -get C:
* Multifunction printers
+
</pre>
* Electronic photo frames
+
* Electronic musical instruments
+
* Standard televisions
+
  
 +
== See Also ==
 +
* [[BitLocker:_how_to_image|BitLocker: How to image]]
 +
* [[Defeating Whole Disk Encryption]]
  
----
+
== External Links ==
  
'''Comparison of FAT Versions''''
+
* [http://en.wikipedia.org/wiki/BitLocker_Drive_Encryption Wikipedia entry on BitLocker]
 +
* [http://www.nvlabs.in/nvbit_bitlocker_white_paper.pdf Accessing Bitlocker volumes from linux], by Nitin Kumar and Vipin Kumar, 2008
 +
* [http://jessekornblum.com/publications/di09.html Implementing BitLocker for Forensic Analysis], ''Digital Investigation'', by Jesse D. Kornblum, 2009
 +
* [https://googledrive.com/host/0B3fBvzttpiiSX2VCRk16TnpDd0U/BitLocker%20Drive%20Encryption%20(BDE)%20format.pdf BitLocker Drive Encryption (BDE) format specification], by the [[libbde|libbde project]], March 2011
 +
* [http://technet2.microsoft.com/WindowsVista/en/library/c61f2a12-8ae6-4957-b031-97b4d762cf311033.mspx?mfr=true Microsoft's Step by Step Guide]
 +
* [http://technet.microsoft.com/en-us/windowsvista/aa906017.aspx Microsoft Technical Overview]
 +
* [http://technet.microsoft.com/en-us/magazine/2009.05.win7.aspx An Introduction to Security in Windows 7]
 +
* [http://www.microsoft.com/whdc/system/platform/hwsecurity/BitLockerFAQ.mspx Microsoft FAQ]
 +
* [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://technet.microsoft.com/en-us/library/hh831412.aspx What's New in BitLocker] in Windows 8
  
Table adapted from:
+
== Tools ==
http://en.wikipedia.org/wiki/File_Allocation_Table
+
* [http://www.hsc.fr/ressources/outils/dislocker/ dislocker]
 +
* [[libbde]]
  
 
+
[[Category:Disk encryption]]
<table cellpadding="2" border="1">
+
[[Category:Windows]]
<tr bgcolor="lightgreen" align="center">
+
<td bgcolor="white"></td>
+
<td><b>FAT12</b></td>
+
<td><b>FAT16</b></td>
+
<td><b>FAT32</b></td>
+
 
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Developer</th>
+
<td colspan="3">Microsoft</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey" rowspan="2">Full Name</th>
+
<td colspan="3">File Allocation Table</td>
+
</tr>
+
<tr align="center">
+
<td>(12-bit version)</td>
+
<td>(16-bit version)</td>
+
 
+
<td>(32-bit version)</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Introduced</th>
+
<td>1977 (Microsoft Disk BASIC)</td>
+
<td>July 1988 (MS-DOS 4.0)</td>
+
 
+
<td>August 1996 (Windows 95 OSR2)</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Partition identifier</th>
+
<td>0x01 (MBR)</td>
+
<td>0x04, 0x06, 0x0E (MBR)</td>
+
 
+
<td>0x0B, 0x0C (MBR)<br />
+
<small>EBD0A0A2-B9E5-4433<br />
+
-87C0-68B6B72699C7</small> (GPT)</td>
+
</tr>
+
<tr bgcolor="lightgreen" align="center">
+
<th>Structures</th>
+
<th><b>FAT12</b></th>
+
 
+
<th><b>FAT16</b></th>
+
<th><b>FAT32</b></th>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Directory contents</th>
+
<td colspan="3">Table</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">File allocation</th>
+
<td colspan="3">Linked List</td>
+
</tr>
+
 
+
<tr align="center">
+
<th bgcolor="lightgrey">Bad blocks</th>
+
<td colspan="3">Linked List</td>
+
</tr>
+
<tr bgcolor="lightgreen" align="center">
+
<th>Limits</th>
+
<th><b>FAT12</b></th>
+
<th><b>FAT16</b></th>
+
<th><b>FAT32</b></th>
+
</tr>
+
<tr align="center">
+
 
+
<th bgcolor="lightgrey">Max file size</th>
+
<td>32 MiB</td>
+
<td>2 GiB</td>
+
<td>4 GiB</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Max number of files</th>
+
<td>4,077</td>
+
 
+
<td>65,517</td>
+
<td>268,435,437</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Max filename size</th>
+
<td colspan="3">8.3 or 255 characters when using LFNs</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Max volume size</th>
+
<td>32 MiB</td>
+
 
+
<td>4 GiB</td>
+
<td>2 TiB</td>
+
</tr>
+
<tr bgcolor="lightgreen" align="center">
+
<th>Features</th>
+
<th><b>FAT12</b></th>
+
<th><b>FAT16</b></th>
+
<th><b>FAT32</b></th>
+
</tr>
+
 
+
<tr align="center">
+
<th bgcolor="lightgrey">Dates recorded</th>
+
<td colspan="3">Creation, modified, access</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Date range</th>
+
<td colspan="3">January 1, 1980 - December 31, 2107</td>
+
 
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Forks</th>
+
<td colspan="3">Not natively</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Attributes</th>
+
<td colspan="3">Read-only, hidden, system, volume label, subdirectory, archive</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Permissions</th>
+
<td colspan="3">No</td>
+
 
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Transparent compression</th>
+
<td colspan="2">Per-volume, Stacker, DoubleSpace, DriveSpace</td>
+
<td>No</td>
+
</tr>
+
<tr align="center">
+
<th bgcolor="lightgrey">Transparent encryption</th>
+
 
+
<td colspan="2">Per-volume only with DR-DOS</td>
+
<td>No</td>
+
</tr>
+
</table>
+
 
+
 
+
----
+
 
+
'''References:'''
+
 
+
http://en.wikipedia.org/wiki/File_Allocation_Table
+
 
+
http://www.microsoft.com
+
 
+
http://www.ntfs.com
+
 
+
http://support.microsoft.com/kb/q154997/#XSLTH3126121123120121120120
+

Revision as of 13:28, 23 December 2013

BitLocker Disk Encryption (BDE) is Full Volume Encryption solution by Microsoft 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. Unlike previous versions of BitLocker, BitLocker To Go allows the user to protect volumes with a password or smart card.

BitLocker

BitLocker encrypts data with either 128-bit or 256-bit AES and optionally using a diffuser 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 key. Some of the key-protectors are:

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

BitLocker has support for partial encrypted volumes.

How to detect

Volumes encrypted with BitLocker will have a different signature than the standard NTFS header.

A BitLocker encrypted volume starts with the "-FVE-FS-" signature.

A hexdump of the start of the volume should look similar to:

00000000  eb 58 90 2d 46 56 45 2d  46 53 2d 00 02 08 00 00  |.X.-FVE-FS-.....|
00000010  00 00 00 00 00 f8 00 00  3f 00 ff 00 00 00 00 00  |........?.......|
00000020  00 00 00 00 e0 1f 00 00  00 00 00 00 00 00 00 00  |................|
00000030  01 00 06 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000040  80 00 29 00 00 00 00 4e  4f 20 4e 41 4d 45 20 20  |..)....NO NAME  |
00000050  20 20 46 41 54 33 32 20  20 20 33 c9 8e d1 bc f4  |  FAT32   3.....|

These volumes can also be identified by the BitLocker GUID/UUID: 4967d63b-2e29-4ad8-8399-f6a339e3d00 or 4967d63b-2e29-4ad8-8399-f6a339e3d01 for BitLocker ToGo.

000000a0  3b d6 67 49 29 2e d8 4a  83 99 f6 a3 39 e3 d0 01  |;.gI)..J....9...|

BitLocker To Go

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 encrypted. The "discovery drive" volume contains BitLocker To Go Reader to read from encrypted volumes on versions of Microsoft Windows without BitLocker support.

manage-bde

To view the BitLocker Drive Encryption (BDE) status on a running Windows system:

manage-bde.exe -status

To obtain the recovery password for volume C:

manage-bde.exe -protectors -get C: -Type recoverypassword

Or just obtain the all “protectors” for volume C:

manage-bde.exe -protectors -get C:

See Also

External Links

Tools