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copy of truecrypt user manual
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2004-02-05 17:56:21 UTC
TRUECRYPT
F R E E O P E N - S O U R C E O N - T H E - F L Y E N C R Y P T I O N
F O R W I N D O W S
USER’S GUIDE
Version Information
TrueCrypt User’s Guide, version 1.0. Released February 2, 2004.
Trademark Information
IDEA is a trademark of Ascom Tech AG. All other registered and
unregistered trademarks in this document
are the sole property of their respective owners.
Licensing and Patent Information
The IDEA cryptographic cipher described in U.S. patent number
5,214,703 requires license from Ascom
Tech AG for commercial use.
Limitations
TrueCrypt Team does not warrant that the information meets your
requirements or that the information is free
of errors. The information may include technical inaccuracies or
typographical errors.
Disclaimer
Before using and installing this product (TrueCrypt), you must agree
to the following terms and conditions:
• You understand that this product utilizes strong cryptography, and
that should this technology be
regulated or illegal in your country, the authors of the product will
not be responsible for any
consequences that your importing and/or using it in such a country
might have.
• You understand that the authors of the product cannot be held
responsible for loss of your data or
any other damage, direct or indirect, caused by using or installing
the product.
• You understand that this product contains no "backdoor", that would
allow partial or complete
recovery of your data without knowing the correct password or
encryption key.
• You understand that the authors of the program cannot help you to
recover your data should you
forget your password.
You must also agree to the TrueCrypt License displayed in the
TrueCrypt Setup window.
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
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CONTENTS
INTRODUCTI4
TRUECRYPT
VOLUME..................................................................................................................4
CREATING A NEW TRUECRYPT VOLUME
..........................................................................................4
Quick Format
...........................................................................................................................4
Cluster Size
..............................................................................................................................5
Additional Notes on Volume
Creation.....................................................................................5
PLAUSIBLE DENIABILITY
..................................................................................................................5
MAIN PROGRAM
WINDOW.........................................................................................................6
Select File.6
Select De6
Mount.......6
Auto-Mount Partitions
.............................................................................................................6
Dismount..7
Dismount
All............................................................................................................................7
Wipe Cac7
Change Password
.....................................................................................................................7
Never Save History
..................................................................................................................7
Exit...........7
PASSWORD ENTRY
............................................................................................................................7
Cache Password in Driver Memory
.........................................................................................7
PROGRAM MENU
...........................................................................................................................8
File -> Exit ...8
Tools -> Clear Volume History
...................................................................................................8
Tools -> Preferences
....................................................................................................................8
SUPPORTED OPERATING
SYSTEMS.........................................................................................9
UNINSTALLING
TRUECRYPT.....................................................................................................9
COMMAND LINE
USAGE..............................................................................................................9
Syntax ......9
Examples10
ENCRYPTION
ALGORITHMS....................................................................................................10
TECHNICAL
DETAILS.................................................................................................................11
ENCRYPTION
SCHEME.....................................................................................................................11
TRUECRYPT VOLUME FORMAT SPECIFICATION
..............................................................................12
HEADER KEY DERIVATION
FUNCTION............................................................................................12
SECTOR SCRAMBLING
.....................................................................................................................13
RANDOM NUMBER GENERATOR
.....................................................................................................13
COMPLIANCE WITH STANDARDS
.....................................................................................................14
TRUECRYPT SYSTEM
FILES.............................................................................................................14
Windows 2000/XP
.................................................................................................................14
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
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2
Windows 98/ME
....................................................................................................................15
KNOWN BUGS AND DEVICE DRIVER LIMITATIONS
........................................................15
Windows 2000/XP
.................................................................................................................15
Windows 98/ME
....................................................................................................................15
FREQUENTLY ASKED
QUESTIONS.........................................................................................16
VERSION
HISTORY......................................................................................................................16
ACKNOWLEDGEMENTS.............................................................................................................19
CONTACT........19
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
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3
PREFACE
This document assumes that the reader is generally familiar with using
computer hardware and
software. Describing a feature that is usually easily understood has
been avoided wherever
possible. For more information, please visit www.truecrypt.org.
Introduction
TrueCrypt is a software system for establishing and maintaining an
on-the-fly-encrypted volume
(data storage device). On-the-fly encryption means that data are
automatically encrypted or
decrypted right before they are loaded or saved, without any user
intervention. No data stored on
an encrypted volume can be read without using the correct password or
encryption key. Until
decrypted, encrypted volume appears to be nothing more than a series
of random numbers. Entire
file system is encrypted (i.e. file names, folder names, contents of
every file, and free space). No
unencrypted data are ever stored on any storage device (they are only
temporarily kept in RAM
during the encryption/decryption process).
TrueCrypt Volume
There are two basic types of TrueCrypt volumes:
• Container
• Partition/device
A TrueCrypt container is a normal file, which can reside on any type
of storage device. It contains
(hosts) a completely independent encrypted virtual disk device.
Container is a file-hosted volume.
A TrueCrypt partition is a hard disk partition encrypted using
TrueCrypt. You can also encrypt
floppy disks, ZIP disks, USB hard disks and other types of storage
devices that allow read/write
access.
Creating a New TrueCrypt Volume
To create a new TrueCrypt volume, click on ‘Create Volume’ in the main
program window.
TrueCrypt Volume Creation Wizard should appear. The Wizard provides
help and information
necessary to successfully create a new TrueCrypt volume. However,
several options deserve
further explanation:
Quick Format
If unchecked, each sector of the new volume will be formatted.
Basically this means that the new
volume will be entirely filled with random data. Quick format is much
faster but may be less secure
because until the whole volume has been filled with files, it may be
possible to tell how much data
it contains (if the space was not filled with random data beforehand).
If you are not sure whether to
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4
enable or disable Quick Format, we recommend that you leave this
option unchecked.
Note that Quick Format can only be enabled when encrypting partitions.
Cluster Size
Cluster is an allocation unit. For example, for a one-byte file, at
least one cluster should be
allocated on FAT file system. When the file grows beyond the cluster
boundary, another cluster is
allocated. Theoretically, this means that the bigger the cluster size,
the more disk space is wasted;
however, the performance is better. If you do not know which value to
use, leave the setting at
default.
Important: Windows 98/ME do not support cluster sizes larger than 32K.
You will not be able to
access a 64K-cluster volume using these operating systems.
TrueCrypt volumes can be reformatted at any later time as FAT12,
FAT16, FAT32, or NTFS. They
behave as standard disk devices so you can right-click the device icon
and select 'Format'.
Additional Notes on Volume Creation
After you click the 'Finish' button in the wizard, there will be a
short delay while your system is
being polled for additional random data, which will be used in
generating the new volume.
TrueCrypt "hooks" the keyboard and mouse from the moment that the
volume creation wizard is
started. All key presses, mouse movements, and various system calls
are all contributing to the
random data collection. The random data are used to create volume
encryption key.
Important: When encrypting an entire hard drive partition or an entire
device (floppy disk, ZIP disk
etc.), all data stored on the device/partition will be lost.
Plausible Deniability
It is impossible to identify a TrueCrypt container or partition. Until
decrypted, a TrueCrypt volume
appears to consist of nothing more than random data (it does not
contain any "signature").
Therefore, it is impossible to prove that a file, a partition or a
device is a TrueCrypt volume and/or
that it has been encrypted.
TrueCrypt container files do not have to have a standard file
extension. They can have any file
extension you like (for example, .raw, .dat, .iso, .img, .rnd, .tc) or
they can have no file extension at
all. TrueCrypt ignores file extensions. If you need plausible
deniability, make sure your TrueCrypt
volumes do not have the .tc file extension (this file extension is
‘officially’ associated with
TrueCrypt).
When formatting a hard disk partition as a TrueCrypt volume, the
partition table (including the
partition type) is never modified. If you intend to use a TrueCrypt
partition and you need plausible
deniability, follow these steps (Windows XP):
1) Right-click My Computer icon on your desktop and select Manage
2) In the list (on the left) click Disk Management (the Storage
sub-tree)
3) If the partition that you want to format as a TrueCrypt has already
been created, right-click it
and select Delete Partition… If the partition has not yet been
created, continue with step 4)
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5
4) Right-click the free space (should be labeled as Unallocated) and
select New Partition…
5) New Partition Wizard should appear now. Follow its instructions. On
the Wizard page called
‘Assign Drive Letter or Path’ select ‘Do not assign a drive letter or
drive path’. Click Next.
6) Select Do not format this partition and click Next.
7) Click Finish.
8) The partition now appears to be “reserved” for future use (and
future reformatting). As it is
unformatted, it can contain any random data, which might, for example,
have resided on the
hard drive since the last time you repartitioned the hard disk.
Therefore, there is no
difference between such an unformatted partition and a TrueCrypt
volume. Now you can
format the partition as a TrueCrypt.
Note: if, instead of an unformatted partition, you format an
NTFS/FAT16/FAT32 partition as
a TrueCrypt, the partition will then appear to be a corrupted
NTFS/FAT16/FAT32 partition.
Main Program Window
Select File
Allows you to select a file-hosted TrueCrypt volume. After you select
it, you can mount it by clicking
‘Mount’ (see below). It is also possible to select a volume by
dragging its icon to the
‘TrueCrypt.exe’ icon (TrueCrypt will be automatically launched then).
Select Device
Allows you to select a TrueCrypt partition or a storage device (such
as floppy disk or ZIP disk).
After it is selected, it can be mounted by clicking ‘Mount’ (see
below). Note: There is a more
comfortable way of mounting TrueCrypt partitions – see ‘Auto-Mount
Partitions’ for more
information.
Mount
To mount a TrueCrypt volume, select a free drive letter from the list
in the main window. Then
select a file or device that hosts the TrueCrypt volume and click
‘Mount’. TrueCrypt now tries to
mount the volume using cached passwords (if there are any) and if none
of them works, it asks you
to enter a password. If you enter the correct password, the volume
will be mounted.
Note that switching users on Windows XP/2000 does not dismount a
successfully mounted
TrueCrypt volume. Also note that when you exit the TrueCrypt
application, the TrueCrypt driver still
continues working and no TrueCrypt volumes are dismounted.
Auto-Mount Partitions
This function allows you to mount TrueCrypt partitions without having
to select them manually (by
clicking ‘Select Device’). TrueCrypt goes through all available
partitions (on all hard drives) one by
one and tries to mount each of them as a TrueCrypt volume. Note that
TrueCrypt partition cannot
be identified, nor the cipher it has been encrypted with. Therefore,
the program cannot directly
“find” TrueCrypt partitions. Instead, it has to try mounting each
(even unencrypted) partition using
all encryption algorithms and all cached passwords (if there are any).
Therefore, be prepared that
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6
this process may take a long time on slow computers. Drive letters
will be assigned starting from
the one that is selected in the drive list in the main window. If the
password you enter is not correct,
mounting is tried using cached passwords (if there are any). If you
enter empty password, only the
cached passwords will be used when attempting to mount partitions.
Dismount
To dismount a TrueCrypt volume basically means to make any access to
the data it contains
impossible. To do so, select a TrueCrypt volume and click on Dismount.
Dismount All
Dismounts all currently mounted TrueCrypt volumes.
Wipe Cache
Clears any passwords cached in driver memory. When there are no
passwords in the cache, this
button is disabled. Up to last four successfully mounted TrueCrypt
volume passwords can be
cached. This allows mounting volumes without having to type their
passwords repeatedly.
Passwords are never saved on any disk – they are only temporarily
stored in RAM. Driver memory
is never swapped to disk. Password caching can be enabled/disabled in
the Preferences (Tools
menu).
Change Password
Allows changing the password of the currently selected TrueCrypt
volume. The main encryption
key remains unchanged. Therefore, reformatting is not necessary and is
not performed (i.e. no
data will be lost after changing the password and the password change
will only take a few
seconds).
Never Save History
If checked, the file names and paths of the last eight mounted volumes
will not be saved in the
history.
Exit
Terminates the TrueCrypt application. The driver continues working and
no TrueCrypt volumes are
dismounted.
Password Entry
Cache Password in Driver Memory
When checked, the volume password you enter will be cached in driver
memory (if the password is
correct). Then, later, volumes can be mounted using the cached
password without having to type it
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7
again. Up to four passwords can be cached. The passwords are never
saved on any disk. They
are only temporarily stored in RAM. Driver memory is never swapped to
disk.
Program Menu
Note: Only the menu items that are not self-explanatory are described
in this documentation.
File -> Exit
Terminates the TrueCrypt application. The driver continues working and
no TrueCrypt volumes are
dismounted.
Tools -> Clear Volume History
Clears the list containing file names and paths of the last eight
successfully mounted TrueCrypt
volumes.
Tools -> Preferences
Wipe cached passwords on exit
If enabled, passwords cached in driver memory will be cleared when
exiting TrueCrypt.
Cache passwords in driver memory
When checked, up to last four successfully mounted TrueCrypt volume
passwords will be cached
in driver memory. Then, later, volumes can be mounted using a cached
password without having
to type it again. The passwords are never saved on any disk. They are
only temporarily stored in
RAM. Driver memory is never swapped to disk.
Open Explorer window for successfully mounted volume
If this option is checked, then after a TrueCrypt volume has been
successfully mounted, an
Explorer window showing the root directory of the volume (e.g. T:\)
will be automatically open.
Close all Explorer windows of volume being dismounted
Sometimes, dismounting a TrueCrypt volume is not possible due to the
fact that some files or
folders located on the volume are in use or “locked”. This also
applies to Explorer windows
displaying directories located on TrueCrypt volumes. When this option
is checked, all such
windows will be automatically closed before dismounting, so that the
user does not have to close
them manually.
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
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8
Supported Operating Systems
TrueCrypt runs on the following operating systems:
• Windows 2003
• Windows XP
• Windows 2000
• Windows ME
• Windows 98
Uninstalling TrueCrypt
To uninstall TrueCrypt, open the Windows control panel and select
‘Add/Remove Programs’, locate
TrueCrypt and click the ‘Add/Remove’ button.
Normally, all TrueCrypt files, including the device driver, should be
removed, and most of the
changes made to the registry should be undone. The uninstall will
never remove any TrueCrypt
volume you may have created.
Command Line Usage
/help or /? displays command line help
/volume or /v file and path name of the volume to mount
/letter or /l driver letter to mounted the volume as
/explore or /e opens an Explorer window after a volume has been
mounted
/beep or /b beeps after a volume has been mounted
/auto or /a automatically mounts the volume
/dismountall or /d dismounts all currently mounted TrueCrypt volumes
/cache or /c enables (Y) or disables (N) the password cache
/history or /h enables (Y) or disables (N) the history
/wipecache or /wc wipes any passwords cached in the driver memory
/password or /p the volume password. If used with parameter of '?', a
password prompt
appears. This increases the level of your privacy in a multi-user
environment
by not displaying the main TrueCrypt window. Instead, only a small
password
dialog box appears.
Syntax
volmount [[/v] volume] [/sd] [/l letter] [/e] [/b] [/p [?] |
[password]]
[/h] etc.
The order of the parameters is not important. Whitespaces between
parameters and parameter
values do not matter.
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9
Examples
Mounting a volume called 'myvolume.tcl' using the password
‘MyPassword’, drive letter X,
TrueCrypt will open an explorer window and beep, mounting will be
automatic:
volmount /v myfile.tc /lx /a /p MyPassword /e /b
Mounting a volume called 'myvolume.tc' using the password prompt:
volmount /v myfile.tc /lx /a /p ? /e /b
Note that turning the cache off will not clear the password cache. Use
both /c and /wc to turn the
cache off, and clear it.
Encryption Algorithms
TrueCrypt volumes can be encrypted using one of the following
algorithms:
Algorithm Author(s) Key Size
(bits)
Block Size
(bits)
Blowfish B. Schneier 448 64
CAST C. Adams, S. Tavares 128 64
IDEA X. Lai, J. Massey 128 64
Triple-DES IBM, NSA 168 64
Each of the encryption algorithms is used in CBC mode (Triple-DES in
inner-CBC). A random
value, unique to each sector and volume, is used as the IV (for more
information, see Sector
Scrambling).
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10
Technical Details
Encryption Scheme
When mounting a TrueCrypt volume (assume there are no cached
passwords), the following steps
are performed:
1. The first 512 bytes of the volume are read into RAM, out of which
the first 64 bytes are the
salt.
2. A password entered by the user and the salt read in (1) are passed
to the key derivation
function (see section Header Key Derivation Function). This function
produces a sequence
of values from which the header encryption key and IV (used to decrypt
the volume header)
are derived.
3. An encryption algorithm is chosen and initialized with the key and
IV obtained in (2). (Note
that it is impossible to directly determine the cipher algorithm that
has been used to encrypt
the volume.)
4. The data read in (1), except the first 64 bytes, are decrypted with
the chosen encryption
algorithm. Note that now it is still unsure whether the chosen
encryption algorithm is correct
or not.
5. If the first 4 bytes of the data decrypted in (4) do not contain
the text string “TRUE”, then the
encryption algorithm is assumed to be incorrect. If there is an
algorithm that decrypting has
not yet been attempted with, the process continues from (3) choosing
such algorithm. If
there are no algorithms remaining, the password is assumed to be
incorrect, and mounting
is terminated.
If the first 4 bytes of the data decrypted in (4) contain the text
string “TRUE”, then a CRC-32
checksum of the last 256 bytes of the data read in (1) is calculated.
If this value matches
the value stored at the 8th byte (see section TrueCrypt Volume Format
Specification) of the
data decrypted in (4), then the password and chosen encryption
algorithm are considered
correct and the process continues with (6). If the values do not
match, then the encryption
algorithm is assumed to be incorrect. If there is an algorithm that
decrypting has not yet
been attempted with, the process continues from (3) choosing such
algorithm. If there are
no algorithms remaining, the password is assumed to be incorrect and
mounting is
terminated.
6. Now we know that we have the correct password and the correct
encryption algorithm. The
minimum program version required to open the volume, stored in data
decrypted in (4), is
checked. If it is not equal or less than the version of the program
that we are using to mount
the volume, mounting is terminated.
7. The encryption routine is reinitialized with the master key
retrieved from the data decrypted
in (4). This key can be used to decrypt any sector of the volume,
except the first one (the
volume header, which has been encrypted using the header key).
Note: The master key was generated during the volume creation and
cannot be changed
later. Volume password change is accomplished by re-encrypting the
volume header using
a new header key (derived from a new password).
8. Now the volume is mounted (registered with the operating system).
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11
For more information pertaining the encryption scheme, see sections
Sector Scrambling and
Header Key Derivation Function.
TrueCrypt Volume Format Specification
TrueCrypt volume has no “signature”. Until decrypted, it appears to
consist of nothing more than
random data. Therefore, it is impossible to identify a TrueCrypt
container or partition.
TrueCrypt volume format version 1 specification:
Offset
(bytes)
Size
(bytes)
Encryption
Status
Description
0
64
68
70
72
76
84
92
256
288
512
64
4
2
2
4
8
8
164
32
224
N/A
Not Encrypted
Encrypted
Encrypted
Encrypted
Encrypted
Encrypted
Encrypted
Encrypted
Encrypted
Encrypted
Encrypted
Salt *
Text string “TRUE”
Volume version
Minimum program version required to open the volume
CRC-32 checksum of the (decrypted) bytes 256-511
Volume creation time
Header creation/modification time
Reserved
Data used to generate IV and ‘whitening’ values
Master encryption key
Data area (the actual volume contents)
*) Note that salt does not need to be encrypted, as it does not have
to be kept secret (salt is a sequence of random values).
The bytes 0-63 (salt), bytes 256-287 (data used to generate IV and
‘whitening’ values), and bytes
288-511 (master encryption key), contain random values that have been
generated using the builtin
random number generator (see section Random Number Generator) during
the volume creation
process.
Header Key Derivation Function
Header key is used to decrypt the encrypted area of the TrueCrypt
volume header (see sections
Encryption Scheme and TrueCrypt Volume Format Specification). The
technique that TrueCrypt
uses to generate header keys conforms to PKCS #5 v2.0 (see
ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-5v2/pkcs5v2-0.pdf). A 64-byte
(512-bit) salt is used, which
means there are 2 to the power of 512 keys for each password. This
significantly decreases
vulnerability to 'off-line' dictionary attacks (precomputing all the
keys for a dictionary of passwords
is very difficult when a salt is used). 2,000 iterations of the key
derivation function have to be
performed to derive a header key, which significantly increases the
time necessary to perform an
exhaustive search for passwords. The header key derivation function is
based on HMAC-SHA-1
(for more information, please see RFC 2104, available at:
http://www.cis.ohio-state.edu/htbin/rfc/rfc2104.html).
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12
Sector Scrambling
Each cipher implemented in TrueCrypt operates in CBC mode (Triple-DES
in inner-CBC). The IV
(initialization vector) is a random value, which is unique to each
sector and volume. This value is
generated as follows:
1. Bytes 256-263 of the decrypted volume header are retrieved (see
sections TrueCrypt
Volume Format Specification and Encryption Scheme).
2. Data retrieved in (2) are XORed with the 64-bit sector number (each
sector is 512 bytes
long; sectors are numbered starting at 0).
Note: Step (1) is only performed once, right after the volume is
mounted. The retrieved value
remains in RAM then.
Every 8 bytes of each sector (after the sector is encrypted) are XORed
with a 64-bit value, which is
unique to each sector and volume. The value is generated as follows:
1. Bytes 264-271 of the decrypted volume header are retrieved (see
sections TrueCrypt
Volume Format Specification and Encryption Scheme).
2. Bytes 272-279 of the decrypted volume header are retrieved.
3. Data retrieved in (1) are XORed with the 64-bit sector number (each
sector is 512 bytes
long; sectors are numbered starting at 0).
4. Data retrieved in (2) are XORed with the 64-bit sector number.
5. A 32-bit CRC-32 value of the first 8 bytes of the resultant value
in (3) is calculated.
6. A 32-bit CRC-32 value of the second 8 bytes of the resultant value
in (3) is calculated.
7. A 32-bit CRC-32 value of the first 8 bytes of the resultant value
in (4) is calculated.
8. A 32-bit CRC-32 value of the second 8 bytes of the resultant value
in (4) is calculated.
9. The value calculated in (5) is XORed with the value calculated in
(8).
10. The value calculated in (6) is XORed with the value calculated in
(7).
11. The 32-bit value calculated in (9) is written to the upper 32-bit
word and the value
calculated in (10) is written to the lower 32-bit word of the 64-bit
‘whitening’ value.
Random Number Generator
The random number generator implemented in TrueCrypt is used to
generate the salt, master
encryption key, IV and ‘whitening’ values.
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13
The random number generator creates a pool of random values in RAM.
The pool, which is 256
bytes long, is periodically filled byte by byte with values derived
from the following sources:
• Mouse movements (CRC32-hashed coordinates and event delta times)
• Mouse clicks (CRC32-hashed event delta times)
• Key presses (CRC32-hashed key codes and event delta times)
• Network interface statistics (NETAPI32) (collected only once in the
beginning)
• Performance statistics of disk devices (collected only once in the
beginning)
• Various Win32 handles, time variables, and counters (collected at
250-ms interval)
Random values are written to the pool by adding (not by replacing the
old values in the pool). This
means that from the moment that a value is written to the pool, it
never stops affecting the state of
it. Additionally, after a value (byte) is added to the pool, the pool
is entirely hashed using a hash
function (SHA-1).
The described random number generation technique is based on the
following:
• Software Generation of Practically Strong Random Numbers by Peter
Gutmann,
(http://www.cs.auckland.ac.nz/~pgut001/pubs/random.pdf)
• Cryptographic Random Numbers by Carl Ellison,
(http://www.clark.net/pub/cme/P1363/ranno.html)
Compliance with Standards
TrueCrypt complies with the following standards and specifications:
• PKCS #5 v2.0
(ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-5v2/pkcs5v2-0.pdf)
• FIPS 180-2 – SHA-1
(http://csrc.nist.gov/publications/fips/fips180-2/FIPS180-
2_changenotice.pdf)
• RFC 2104 – HMAC
(http://www.cis.ohio-state.edu/htbin/rfc/rfc2104.html)
• RFC 2202 – HMAC-SHA-1
(http://www.cis.ohio-state.edu/htbin/rfc/rfc2202.html)
• FIPS 46-3 – Triple-DES
(http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf)
TrueCrypt System Files
WindowsPath\TrueCryptSetup.exe (uninstaller)
Windows 2000/XP
WindowsPath\SYSTEM32\DRIVERS\truecrypt.sys (driver)
WindowsPath\SYSTEM32\TrueCryptService.exe (service)
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14
The service is necessary to register each newly mounted volume with
the operating system (Mount
Manager), which then assigns a drive letter to it. The service also
allows users without
administrator privileges to dismount TrueCrypt volumes.
Windows 98/ME
WindowsPath\SYSTEM\IOSUBSYS\truecrypt.vxd (driver)
Note: Replace WindowsPath with your Windows installation path (e.g.
C:\WINDOWS)
Known Bugs and Device Driver Limitations
Windows 2000/XP
• Network volumes are not supported.
• Raw floppy disk volumes: when a floppy disk is ejected and another
one is inserted,
garbage will be read/written to the disk, which could lead to data
corruption. This affects
only raw floppy disk volumes (not containers stored on floppy disks).
Windows 98/ME
• The driver is single-threaded. Under Windows 2000/XP it is possible
to store one TrueCrypt
volume within another, and mount both volumes (since the Windows
2000/XP driver is
multi-threaded). This is not possible under Windows 98/ME and should
not be attempted.
• Raw floppy disk volumes are not supported.
• TrueCrypt volumes must be dismounted manually.
• Up to eight TrueCrypt volumes can be mounted at a time.
• The driver incorrectly allows the OS to ‘believe’ that the very
first write to a read-only
volume (i.e. a floppy disk with the write protection on) has been
successful. This, for
example, makes the OS consider a file updated, when it actually is
not. Upon a subsequent
write, the OS correctly reports the volume as write protected.
If you find a bug, please send us a bug report at ***@truecrypt.org
and if possible, include the
following information:
• Name and version of the operating system
• Service pack version, if applicable
• TrueCrypt version
• Encryption algorithm
• TrueCrypt volume size and type (whether it is a device, partition,
or a file-hosted volume)
• What applications were running and what was going on at the time
when the bug occurred
• Full error report
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
***@truecrypt.org
15
Frequently Asked Questions
For the latest version of TrueCrypt FAQ please see:
www.truecrypt.org/faq.html
Version History
1.0
February 2, 2004
Note: TrueCrypt is based on E4M (Encryption for the Masses).
Therefore, the following list contains
differences between E4M 2.02a and TrueCrypt 1.0 (minor differences
have been omitted).
Improvements:
• Windows XP/2000 support
• The maximum volume size is 18,446,744,073 GB (E4M only allows 2 GB).
Note: File system, hardware connection standard, and operating system
limitations have to be taken
into account when determining maximum volume size.
• Plausible deniability. It is impossible to identify a TrueCrypt
container or partition. Until decrypted, a
TrueCrypt volume appears to consist of nothing more than random data
(it does not contain any
"signature"). Therefore, it is impossible to prove that a file, a
partition or a device is a TrueCrypt
volume and/or that it has been encrypted. To achieve plausible
deniability, the format of the volume
and the encryption process had to be significantly changed.
• The salt is 64 bytes long now (E4M uses 20 bytes).
• The iteration count of the key derivation function increased to
2,000 (E4M uses 1,000).
• Free space is filled with random data during volume creation,
instead of filling it with zeroes. This
reduces the amount of predictable plaintext and, in future, will
increase the level of plausible deniability
of hidden volumes.
• Up to 32 partitions per physical disk drive can be encrypted now
(Windows XP/2000).
• The minimum volume password length has been increased to 12
characters.
• The maximum volume password length has been decreased from 100 to 64
characters. This was
necessary to avoid the following: When a password longer than 64
characters was passed to HMACSHA-
1, the whole password was first hashed using SHA-1 and the resultant
160-bit value was then
used instead of the original password (which complies with HMAC-SHA-1
specification), thus the
password length was in fact reduced.
• The Blowfish key length size has been increased to 448 bits.
Remark: Even though our increasing the key size to 448 bits might
appear to be a significant overkill,
there was no reason for us not to do so (note that there is no
decrease in speed of
encryption/decryption).
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
***@truecrypt.org
16
Bug fixes:
• Sector scrambling algorithm flaw fixed. Two or more disk sectors to
be encrypted consisting of the
same values (e.g. filled with zeroes), after being encrypted by E4M,
start with the same 8-byte
sequence of values (i.e. the first eight bytes of any of these
encrypted sectors contain the same values
as the first eight bytes of any other of these encrypted sectors). If
this had not been fixed, the
plausible deniability would not have been possible.
• TrueCrypt volumes can be dismounted (Windows XP issue).
• "Blue screen" errors no longer occur during Windows shutdown when
there is one or more mounted
TrueCrypt volumes.
• Drive geometry is calculated correctly now (chkdsk.exe and
format.exe do not fail anymore).
• A TrueCrypt volume can be reformatted as FAT32 or NTFS using the
Windows built-in format tool
(Windows XP/2000 issue).
• Windows Check Disk can now be used on TrueCrypt volumes (Windows
XP/2000 issue).
• Windows Disk Defragmenter can now be used on encrypted volumes
(Windows XP/2000 issue).
New features:
• New IV (initialization vector) generation algorithm (see the
documentation for more information)
• Every 8 bytes of each sector (after the sector is encrypted) are
XORed with a random 64-bit value,
which is unique to each sector and volume (sector is 512 bytes long).
This makes obtaining a
plaintext/ciphertext pair a bit more difficult.
• New function to clear the volume history.
• When selecting a partition/device, the sizes and file system types
of available partitions/devices are
displayed (Windows XP/2000).
• List of mounted TrueCrypt volumes now contains their sizes and
encryption algorithms used (Windows
XP/2000).
• Free volume space is reported (in 'My Computer' list etc.)
• Windows XP format facilities do not support formatting volumes
larger than 32 GB as FAT32. However,
with TrueCrypt Volume Creation Wizard it is now possible to create
FAT32 volumes larger than 32 GB.
• New function that allows multiple TrueCrypt partitions to be mounted
provided that their correct
password(s) has/have been entered (this includes the cached passwords,
if there are any).
• Quick format (partitions/devices only)
• Cluster size selection (when creating new volumes)
• Volume properties can now be examined (encryption algorithm, volume
creation time, last password
change time etc.)
• New function to dismount all mounted TrueCrypt volumes.
• New command line options to dismount all mounted TrueCrypt volumes:
/d and /dismountall
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
***@truecrypt.org
17
• HMAC-SHA1 and CRC-32 algorithm tests are now included in the
self-test facility.
• Program menu and Preferences window added.
• Custom user interface fonts supported.
• Optionally, the TrueCrypt installer can now create System Restore
points (Windows XP/ME).
• Password input field is wiped after a correct volume password has
been entered.
• New graphics, icons, user interface
• New documentation
Removed features:
• E4M and SFS volumes are no longer supported.
• DES cipher removed.
• HMAC-MD5 removed (to be replaced by HMAC-RIPEMD-160).
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
***@truecrypt.org
18
Acknowledgements
Thanks to:
• Paul Le Roux for making his E4M source code available. TrueCrypt is
based on E4M.
For information on differences between E4M and TrueCrypt, please see
Version History.
• Eric Young for writing his excellent libdes, libcast etc., which
were the sources of some of
the cryptography code used in E4M.
• Peter Gutmann for his paper on random numbers, and for creating his
cryptlib, which was
the source of parts of the random number generator source code used in
E4M.
• Andy Neville for providing some of the code and inspiration, useful
in the implementation of
the file-hosted volumes (E4M).
• Shaun Hollingworth (aka Aman), who allowed Paul Le Roux to develop
the E4M driver for
Windows 98/ME using the Scramdisk source code.
• David Kelvin, who added the privacy password command line argument,
and the quiet
mode.
Contact
TrueCrypt team can be contacted at:
***@truecrypt.org
For more information on ways to contact us, please see:
www.truecrypt.org/contact.html
Copyright © 2004 TrueCrypt Team • www.truecrypt.org •
***@truecrypt.org
19
Peter Gutmann
2004-02-06 02:48:09 UTC
Post by Crabbit
IDEA is a trademark of Ascom Tech AG. All other registered and
unregistered trademarks in this document
are the sole property of their respective owners.
Licensing and Patent Information
The IDEA cryptographic cipher described in U.S. patent number
5,214,703 requires license from Ascom
Tech AG for commercial use.
Limitations
Could that be what SCOStar are alluding to with their "had no right to use"
claim? If you're creating a commercial product you need a license for IDEA
(which presumably they bought if they use IDEA in DriveCrypt). However, for
non-commercial (freely available) software you don't need a license, a fact
that either escaped them or that they're deliberately ignoring.

Peter.
Jeff
2004-02-06 08:31:50 UTC
Post by Peter Gutmann
Post by Crabbit
IDEA is a trademark of Ascom Tech AG. All other registered and
unregistered trademarks in this document
are the sole property of their respective owners.
Licensing and Patent Information
The IDEA cryptographic cipher described in U.S. patent number
5,214,703 requires license from Ascom
Tech AG for commercial use.
Limitations
Could that be what SCOStar are alluding to with their "had no right to
use" claim? If you're creating a commercial product you need a
license for IDEA (which presumably they bought if they use IDEA in
DriveCrypt). However, for non-commercial (freely available) software
you don't need a license, a fact that either escaped them or that
they're deliberately ignoring.
Peter.
Good point. Going to call Ascom (local call) and ask them if SecurStar
has acquired the appropriate license for IDEA.