EWF specification

Summary

EWF is short for Expert Witness Compression Format, according to [ASR02]. It is a file type used to store media images for forensic purposes. It is currently widely used in the field of computer forensics in proprietary tooling like EnCase en FTK. The original specification of the format is provided by ASRDATA, for the SMART application.

The EWF format was succeeded by the Expert Witness Compression Format version 2 in EnCase 7 (EWF2-Ex01 and EWF2-Lx01). EnCase 7 also uses a different version of EWF-L01 then its predecessors.

This document is intended as a working document of the data format specification for the libewf project.

Document information

Author(s):	Joachim Metz <joachim.metz@gmail.com>
Abstract:	This document contains the EWF file format specification.
Classification:	Public
Keywords:	Expert Witness Compression Format, EWF, EnCase file format, SMART

License

Copyright (C) 2006-2023, Joachim Metz <joachim.metz@gmail.com>.
Permission is granted to copy, distribute and/or modify this document under the
terms of the GNU Free Documentation License, Version 1.3 or any later version
published by the Free Software Foundation; with no Invariant Sections, no
Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included
in the section entitled "GNU Free Documentation License".

Revision history

Version	Author	Date	Comments
0.0.1	J.B. Metz	March 2006	Initial version
0.0.2	J.B. Metz	March 2006	Additional information.
0.0.3	J.B. Metz	March 2006	Additional information.
0.0.4	J.B. Metz	March 2006	Additional information.
0.0.5	J.B. Metz	March 2006	Additional information, regarding data and header2 section.
0.0.6	J.B. Metz	March 2006	Additional information, regarding data and header2 section.
0.0.7	J.B. Metz	March 2006	Additional information, regarding data, hash and header2 section.
0.0.8	J.B. Metz	March 2006	Additional information, regarding data section.
0.0.9	J.B. Metz	March 2006	Additional information, regarding chunk and compression, offset array CRC and error2 section.
0.0.10	J.B. Metz	March 2006	Correction regarding EnCase 3 and compression MSB.
0.0.11	J.B. Metz	March 2006	Additions regarding EnCase 2.
0.0.12	J.B. Metz	March 2006	Small changes regarding unknown in volume and data. Removed some spelling errors. Added the information regarding when a chunk is compressed or not.
0.0.13	J.B. Metz	April 2006	Additions regarding EnCase 1.
0.0.14	J.B. Metz	April 2006	Additions regarding byte order.
0.0.15	J.B. Metz	April 2006	Additions regarding disk section.
0.0.16	J.B. Metz	April 2006	Small adjustments regarding header section.
0.0.17	J.B. Metz	April 2006	Adjustments in error2 section information.
0.0.18	J.B. Metz	May 2006	Adjustments in hash section information.
0.0.19	J.B. Metz	August 2006	Fixed error in EnCase 4 header2 layout information.
0.0.20	J.B. Metz	August 2006	Added information regarding SMART format generated by FTK Imager. Corrected error about gzip compression in header section.
0.0.21	J.B. Metz	August 2006	Added information regarding SMART format generated by FTK Imager.
0.0.22	J.B. Metz	August 2006	Added information about segment file extension naming.
0.0.23	J.B. Metz	September 2006	Added information about EWF-L01 (LVF) format.
0.0.24	J.B. Metz	September 2006	Added information from EWF-L01 analysis.
0.0.25	J.B. Metz	September 2006	Changes after comments by Guy Voncken.
0.0.26	J.B. Metz	October 2006	Corrected error regarding EnCase 1 and SMART header specification.
0.0.27	J.B. Metz	October 2006	Added theoretical maximum media size.
0.0.28	J.B. Metz	October 2006	Additional information about section start size in EnCase (EWF-E01) next and done sections.
0.0.29	J.B. Metz	November 2006	Additional information about CRC algorithm.
0.0.30	J.B. Metz	November 2006	Fixed error regarding the location of the actual chunks in the EnCase 1 format, which actually is the table sections and not the sectors section.
0.0.31	J.B. Metz	November 2006	Additional information about the EnCase linen 5 (EWF-E01) format.
0.0.32	J.B. Metz	December 2006	Additional information about GUID.
0.0.33	J.B. Metz	December 2006	Corrected error regarding header sections in EnCase 1 format.
0.0.34	J.B. Metz	December 2006	Added new information regarding the table section after encountering a bug in FTK for EWF files with more than 16 x 1024 offset table entries.
0.0.35	J.B. Metz	December 2006	Corrected misinterpretation of original specifications, regarding additional table sections.
0.0.36	J.B. Metz	January 2007	Added information about EnCase 6.
0.0.37	J.B. Metz	January 2007	Added information about linen 6.
0.0.38	J.B. Metz	January 2007	Added information about EnCase6/linen6 header and adjustments regarding media type and media flags.
0.0.39	J.B. Metz	January 2007	Added information about header values.
0.0.40	J.B. Metz	January 2007	Added information about EWF-X
0.0.41	J.B. Metz	August 2007	Added information about EnCase 6.7 >2Gb segment file support.
0.0.42	J.B. Metz	August 2007	Added information about EnCase 6.7 >2Gb segment file support and CD/DVD image session sector.
0.0.43	J.B. Metz	September 2007	Added information about EnCase 6.7 >2Gb segment file support.
0.0.44	J.B. Metz	September 2007	Added page numbers.
0.0.45	J.B. Metz	November 2007	Added information about session section.
0.0.46	J.B. Metz	March 2008	Added information about session section.
0.0.47	J.B. Metz	March 2008	Added information about EnCase 6 >2GiB segment file format.
0.0.48	J.B. Metz	June 2008	Textual corrections.
0.0.49	J.B. Metz	June 2008	Added information about EnCase 6.11 winen file format.
0.0.50	J.B. Metz	February 2009	Added information about EnCase 6.12 SHA1 hash support and header values.
0.0.51	J.B. Metz	April 2009	Added information about EnCase software version header value limitation.
0.0.52	J.B. Metz	April 2009	Added information about EnCase 6.13 Tableau write blocker support.
0.0.53	J.B. Metz	November 2009	Small changes.
0.0.54	J.B. Metz	December 2009 January 2010	Added information about ltree section.
0.0.55	J.B. Metz	January 2010	Update for linen 6.12 and later.
0.0.56	J.B. Metz	May 2010	Corrected amount of into number of and email change
0.0.57	J.B. Metz	September 2010	Minor changes.
0.0.58	J.B. Metz	September 2010	Changed CRC to checksum.
0.0.59	J.B. Metz	October 2010	Additional session section information with thanks to M. Nohr, updated some tables to the newer format and minor changes.
0.0.60	J.B. Metz	November 2010	Minor changes and improvements with thanks to G. Voncken and updated some tables to the newer format.
0.0.61	J.B. Metz	December 2010	License version update, additional information about optical discs and AD encryption.
0.0.62	J.B. Metz	January 2011	Minor changes
0.0.63	J.B. Metz	February 2011	Additional audio tracks information with thanks to M. Nohr
0.0.64	J.B. Metz	May 2011	Changes to FTK imager format
0.0.65	J.B. Metz	June 2011	Updated Logical File Evidence (LVF) format flag information with thanks to B. Baron.
0.0.66	J.B. Metz	September 2011	Updated Logical File Evidence (LVF) format flag information with thanks to N. Harris
0.0.67	J.B. Metz	December 2011	Small refinement in compressed vs uncompressed chunk data.
0.0.68	J.B. Metz	February 2012	Added information about EnCase header values limitations thanks to G. Voncken.
0.0.69	J.B. Metz	June 2012	Added information about EnCase 6.19 and 7, EWF-E01 and EWF-L01 format. Email change; text clean up; some corrections and additions.
0.0.70	J.B. Metz	July 2012	Changes to match EWF version 2 documentation.
0.0.71	J.B. Metz	July 2012	Updates regarding ltree header.
0.0.72	J.B. Metz	July 2012	Updates files created by Expert Witness 1.35 (for Windows) and other small corrections.
0.0.73	J.B. Metz	August 2012	Updates regarding ltree header.
0.0.74	J.B. Metz	August 2012	Updates regarding incomplete section and corruption scenarios with thanks to B. Johnson for pointing out the dual image scenario.
0.0.75	J.B. Metz	September 2012	Additional information regarding L01 map entry.
0.0.76	J.B. Metz	January 2013	Corrected some typos, thanks to A. Bridge for pointing these out.
0.0.77	J.B. Metz	March 2013	Additional information regarding Logicube created E01 files with thanks to D. Kovar and Digital Assembly LLC.
0.0.78	J.B. Metz	March 2013	Improved description of zlib compressed data format (RFC1950) and deflate compression (RFC1951) and updated the information regarding Logicube products and the data section checksum behavior.
0.0.79	J.B. Metz	August 2015	Switched to asciidoc format.
0.0.80	J.B. Metz	April 2016	Updates regarding ltree.
0.0.81	Z. Travis	May 2017	Details of AD encryption
0.0.82	J.B. Metz	December 2019	Formatting changes and additional information regarding L01 files with thanks to K. Stone.
0.0.83	J.B. Metz	November 2020	Additional information about corruption scenario.
0.0.84	J.B. Metz	July 2023	Additional information about encoding and special characters in ltree names with thanks to J. Dua and P. Livingstone.
0.0.85	J.B. Metz	July 2023	Additional information regarding ltree.

1. Overview

The Expert Witness Compression Format (EWF) is used to store media images. It allows to store disk and partition images, compressed or non-compressed. EWF can store a single image in one or more segment files. Each segment file consist of a standard header, followed by multiple sections. A single section cannot span multiple files. Sections are arranged back-to-back.

Specifications:

In this document when referred to the EWF format it refers to the original specification by [ASR02]. The newer formats like that of EnCase are deducted from the original specification and will be referred to as the EWF-E01, because of the default file extension. Whereas the Logical File Evidence (LVF) format introduced in EnCase 5, which is also stored in the EWF format will be referred to as EWF-L01. The SMART format is viewed separately to allow for discussion if the implementation differs from the specification by [ASR02] and will be referred to as the EWF-S01, because of the default file extension.
All offsets are relative to the beginning of an individual section, unless otherwise noted. EnCase allows a maximum size of a segment file to be 2000 MiB. This has to do with the size of the offset of the chunk of media data. This is a 32 bit value where the most significant bit (MSB) is used as a compression flag. Therefore the maximum offset size (31 bit) can address about 2048 MiB. In EnCase 6.7 an addition was made to the table value to provide for a base offset to allow for segment files greater than 2048 MiB.
A chunk is defined as the sector size (per default 512 bytes) multiplied by the block size, the number of sectors per chunk (block) (per default 64 sectors). The data within the EWF format is stored in little-endian. The terms block and chunk are used intermittently.

1.1. Test version

The following version of programs were used to test the information within this document:

FTK Imager 2.3, 2.4, 2.51, 2.9, 3.0 (Windows)
Expert Witness 1.35 (for Windows) (EnCase 1.35)
EnCase 1.99l (Windows)
EnCase 2.17a (DOS)
EnCase 3.21b (Windows)
EnCase 4.22 (Windows)
EnCase 5.04a, 5.05 (Windows)
EnCase 6.1, 6.7, 6.8, 6.10, 6.11, 6.12, 6.13, 6.14, 6.19 (Windows)
EnCase 7.04 (Windows)
Linen 5 (Linux)
Linen 6.01, 6.19 (Linux)
Linen 7.01 (Linux)

EnCase 7 no longer provides the fast and best compression options.

2. Segment file

EWF stores data in one or more segment files (or segments). Each segment file consists of:

A file header.
One or more sections.

2.1. File header

Each segment file starts with a file header.

[ASR02] defines that the file header consists of 2 parts, namely:

a signature part
fields part

2.1.1. EWF, EWF-E01 and EWF-S01

This is file header is defined by [ASR02] and both used by the EWF-E01 and EWF-S01 formats.

The file header is 13 bytes of size and consists

Offset	Size	Value	Description
0	8		Signature "EVF\x09\x0d\x0a\xff\x00"
8	1	0x01	Start of fields
9	2		Segment number Must be 1 or higher
11	2	0x0000	End of fields

Segment number contains a number which refers to the number of the segment file, starting with 1 for the first file.

Note	This means there could only be a maximum of 65535 (0xffff) files, if it is an unsigned value.

2.1.2. EWF-L01

This is file header is used by the EWF-L01 format.

The file header is 13 bytes of size and consists

Offset	Size	Value	Description
0	8		Signature "LVF\x09\x0d\x0a\xff\x00"
8	1	0x01	Start of fields
9	2		Segment number Must be 1 or higher
11	2	0x0000	End of fields

Segment number contains a number which refers to the number of the segment file, starting with 1 for the first file.

Note	This means there could only be a maximum of 65535 (0xffff) files, if it is an unsigned value.

2.2. Segment file extensions

Both the SMART (EWF-S01) and the EWF-E01 use a different approach for naming the segment files.

2.2.1. EWF-S01

The EWF-S01 extension naming has two distinct parts.

The first segment file has the extension '.s01'.
- The next segment file has the extension '.s02.
- This will continue up to '.s99'.
After which the next segment file has the extension '.saa'.
- The next segment file has the extension '.sab'.
- This will continue up to '.saz'.
- The next segment file has the extension '.sba'.
- This will continue up to '.szz'.
- The next segment file has the extension '.faa'.
- This will continue up to '.zzz'. (verify this; and then ?)
- It will even continue to the use the extensions '.{aa'. (not confirmed)

libewf supports extensions up to .zzz

2.2.2. EWF-E01

The EWF-E01 extension naming has two distinct parts.

The first segment file has the extension '.E01'.
- The next segment file has the extension '.E02.
- This will continue up to '.E99'.
After which the next segment file has the extension '.EAA'.
- The next segment file has the extension '.EAB'.
- This will continue up to '.EAZ'.
- The next segment file has the extension '.EBA'.
- This will continue up to '.EZZ'.
- The next segment file has the extension '.FAA'.
- This will continue up to '.ZZZ'. (verify this; and then ?)
- It will even continue to the use the extensions '.[AA'. (not confirmed)

libewf supports extensions up to .ZZZ

2.2.3. EWF-L01

The EWF-L01 extension naming has two distinct parts.

The first segment file has the extension '.L01'.
- The next segment file has the extension '.L02.
- This will continue up to '.L99'.
After which the next segment file has the extension '.LAA'.
- The next segment file has the extension '.LAB'.
- This will continue up to '.LAZ'.
- The next segment file has the extension '.LBA'.
- This will continue up to '.LZZ'.
- The next segment file has the extension '.MAA'.
- This will continue up to '.ZZZ'. (verify this; and then ?)
- It will even continue to the use the extensions '.[AA'. (not confirmed)

libewf supports extensions up to .ZZZ

2.3. Segment file set identifier GUID

Segment file sets do not have a strict unique identifier. However the volume section contains a GUID that can be used for this purpose. Where:

linen 5 to 6 use a time and MAC address based version (1) of the GUID
EnCase 5 to 7 and linen 6 to 7 use a random based version (4) of the GUID

In linen 6 the switch from a version 1 to 4 GUID was somewhere made between version 6.01 and 6.19.

See RFC4122 for more information about the different GUID versions.

3. The sections

The remainder of the segment file consists of sections. Every section starts with the same data this will be referred to as the section descriptor (previously referred to as section start). The section descriptor could also be referred as the section header, but this allows for unnecessary confusion with the header section.

3.1. Section descriptor

The section descriptor consist of 76 bytes, it contains information about a specific section.

Offset	Size	Value	Description
0	16		A string containing the section type definition. E.g. "header", "volume", etc.
16	8		Next section offset The offset is relative from the start of the segment file
24	8		Section size
32	40	0x00	Padding
72	4		Checksum Adler-32 of all the previous data within the section descriptor.

Some sections contain additional data, refer to paragraph section types for more information.

Note	In EnCase 2 DOS version the padding itself does not contains zero byte values but data, probably the memory is not wiped.

Note	Expert Witness 1.35 (for Windows) does not set the section size.

3.2. Section types

There are multiple section types. [ASR02] defines the following:

Header section
Volume section
Table section
Next and Done section

Looking at more recent EnCase file (EWF-E01) formats and [COH] additional section types were found:

Header2 section
Disk section
Sectors section
Table2 section
Data section
Errors2 section
Session section
Hash section
Digest section

Looking at the more recent EnCase file (EWF-L01) format additional section types were found:

Ltree section
Ltypes section

3.3. Header2 section

The header2 section is identified in the section data type field as "header2". Some aspects of this section are:

Found in EWF-E01 in EnCase 4 to 7, and EWF-L01 in EnCase 5 to 7
Found at the start of the first segment file. Not found in other segment files.
The same header2 section is found twice directly after one and other.

The additional data this section contains is the following:

Offset	Number of bytes	Description
76 (0x4c)	(variable)	Information about the acquired media.

The information about the acquired media consists of zlib compressed data (see section: Compression). It contains text in UTF16 format specifying information about the acquired media. The text multiple lines separated by an end of line character(s).

The first 2 bytes of the UTF16 string are the byte order mark (BOM):

0xff 0xfe for UTF-16 litte-endian
0xfe 0xff for UTF-16 big-endian

In the next paragraphs the various variants of the header2 section are described.

3.3.1. EnCase 4 (EWF-E01)

In EnCase 4 (EWF-E01) the header2 information consist of 5 lines, and contains the equivalent information as the header section.

Line number	Value	Description
1	1	The number of categories provided
2	main	The name/type of the category provided
3		Identifiers for the values in the 4th line
4		The data for the different identifiers in the 3rd line
5		(an empty line)

The end of line character(s) is a newline (0x0a).

Note	This end of line character differs from the one used in the header section.

The 3rd and the 4th line consist of the following tab (0x09) separated values.

Identifier number	Character in 3rd line	Value in 4th line
1	a	Unique description
2	c	Case number
3	n	Evidence number
4	e	Examiner name
5	t	Notes
6	av	Version The EnCase version used to acquire the media
7	ov	Platform The platform/operating system used to acquire the media
8	m	Acquisition date and time
9	u	System date and time
10	p	Password hash

For more information see section: Header2 values

Note	The hashing algorithm is the same as for the header section.

3.3.2. EnCase 5 to 7 (EWF-E01)

In EnCase 5 to 7 (EWF-E01) the header2 information consist of 17 lines, and contains:

Line number	Value	Description
1	3	The number of categories provided
2	main	The name/type of the category provided
3		Identifier for the values in the category
4		The data for the different identifiers in the category
5		(an empty line)
6	srce	The name/type of the category provided See section: Sources category
7
8		Identifier for the values in the category
9		The data for the different identifiers in the category
10
11		(an empty line)
12	sub	The name/type of the category provided See section: Subjects category
13
14		Identifier for the values in the category
15		The data for the different identifiers in the category
16
17		(an empty line)

The end of line character(s) is a newline (0x0a).

Main category

The 3rd and the 4th line consist of the following tab (0x09) separated values.

Note	The actual values in this category are dependent on the version of EnCase.

Identifier number	Character in 3rd line	Value in 4th line
1	a	Unique description
2	c	Case number
3	n	Evidence number
4	e	Examiner name
5	t	Notes
6	md	The model of the media, i.e. hard disk model (introduced in EnCase 6)
7	sn	The serial number of media (introduced in EnCase 6)
8	l	The device label (introduced in EnCase 6.19)
9	av	Version The EnCase version used to acquire the media EnCase limits this value to 12 characters
10	ov	Platform The platform/operating system used to acquire the media
11	m	Acquisition date and time
12	u	System date and time
13	p	Password hash
14	pid	Process identifier The identifier of the process memory acquired (introduced in EnCase 6.12/Winen 6.11)
15	dc	Unknown
16	ext	Extents The extents of the process memory acquired (introduced in EnCase 6.12/Winen 6.11)

For more information see section: Header2 values

Notes

Both the acquiry and system date and time are empty in a file created by winen.

The date values in the header section (not header2) are set to: Thu Jan 1 00:00:00 1970. Where the time is dependent on the time zone and daylight savings.

Sources category

Line 6 the srce category contains information about acquisition sources.

TODO describe what a source is in the context of EnCase.

Line 7 consists of 2 values, namely the values are "0 1".

The 8th line consist of the following tab (0x09) separated values. Note that the actual values in this category are dependent on the version of EnCase.

Identifier number	Character in 8rd line	Meaning
1	p
2	n
3	id	Identifier Contains an integer identifying the source
4	ev	Evidence number Contains a string
5	tb	Total bytes Contains an integer
6	lo	Logical offset Contains an integer which is -1 when value is not set
7	po	Physical offset Contains an integer which is -1 when value is not set
8	ah	MD5 hash Contains a string with the MD5 hash of the source
9	sh	SHA1 hash Contains a string with the SHA1 hash of the source (introduced in EnCase 6.19)
10	gu	Device GUID Contains a string with a GUID or "0" if not set
11	pgu	Primary device GUID Contains a string with a GUID or "0" if not set (introduced in EnCase 7)
12	aq	Acquisition date and time Contains an integer with a POSIX timestamp

Line 9 consists of 2 values, namely the values are "0 0".

Line 10 contains the values defined by line 8.

Note	The default values of some of these values has changed around EnCase 6.12.

If the "ha" value contains "00000000000000000000000000000000" this means the MD5 hash is not set. The same applies for the "sha" value when it contains "0000000000000000000000000000000000000000" the SHA1 has is not set.

Subjects category

Line 12 the sub category contains information about subjects.

TODO describe what a subject is in the context of EnCase.

Line 13 consists of 2 values, namely the values are "0 1".

The 14th line consist of the following tab (0x09) separated values.

Identifier number	Character in 14rd line	Meaning
1	p
2	n
3	id	Identifier Contains an integer identifying the subject
4	nu	Unknown (Number)
5	co	Unknown (Comment)
6	gu	Unknown (GUID)

Line 15 consists of 2 values, namely the values are "0 0".

Line 16 contains the values defined by line 14. Note that the default values of some of these values has changed around EnCase 6.12.

3.3.3. EnCase 5 to 7 (EWF-L01)

The EnCase 5 to 7 (EWF-E01) header2 section specification also applies to the EnCase 5 to 7 (EWF-L01) format. However:

both the acquired and system date and time are not set

3.3.4. Header2 values

Identifier	Description	Notes
a	Unique description	Free form string Note that EnCase might not respond when this value is large e.g. >= 1 MiB
c	Case number	Free form string EnCase limits this string to 3000 - 1 characters
n	Evidence number	Free form string EnCase limits this string to 3000 - 1 characters
e	Examiner name	Free form string EnCase limits this string to 3000 - 1 characters
t	Notes	Free form string EnCase limits this string to 3000 - 1 characters
md	Model	Free form string EnCase limits this string to 3000 - 1 characters
sn	Serial Number	Free form string EnCase limits this string to 3000 - 1 characters
l	Device label	Free form string
av	Version	Free form string EnCase limits this string to 12 - 1 characters
ov	Platform	Free form string EnCase limits this string to 24 - 1 characters
m	Acquisition date and time	String containing POSIX 32-bit epoch timestamp E.g. "1142163845" which represents the date: March 12 2006, 11:44:05
u	System date and time	String containing POSIX 32-bit epoch timestamp E.g. "1142163845" which represents the date: March 12 2006, 11:44:05
p	Password hash	String containing the password hash. If no password is set it should be simply the character '0'.
pid	Process identifier	String containing the process identifier (pid) number
dc	Unknown
ext	Extents	extents contains: number of entries entries that consist of: S <1> <2> <3>

Note	The restrictions were tested with EnCase 7.02.01, older versions could have a restriction of 40 characters instead of 3000 characters.

3.4. Header section

The header section is identified in the section data type field as "header". Some aspects of this section are:

It is defined in the EWF format [ASR02].
Found in EWF-E01 in EnCase 1 to 7 or linen 5 to 7 or FTK Imager, EWF-L01 in EnCase 5 to 7, and SMART (EWF-S01)
Found at the start of the first segment file or in EnCase 4 to 7 after the header2 section in the first segment file. Not found in other segment files.

The additional data this section contains is the following

Offset	Number of bytes	Description
76 (0x4c)	(variable)	Information about the acquired media.

The information about the acquired media consists of zlib compressed data (see section: Compression). It contains text in ASCII format specifying information about the acquired media. The text multiple lines separated by an end of line character(s).

In the next paragraphs the various variants of the header section are described. In all cases the information consists of at least 4 lines:

Line number	Value	Description
1	1	The number of categories provided
2	main	The name/type of the category provided
3		Identifiers for the values in the 4th line
4		The data for the different identifiers in the 3rd line

An additional 5th line is found in FTK Imager, EnCase 1 to 7 (EWF-E01).

5		(an empty line)

3.4.1. EWF format

Some aspects of this section are:

[ASR02] specifies the end of line character(s) is a newline (0x0a).

According to [ASR02] the 3rd and the 4th line consist of the following tab (0x09) separated values:

Identifier number	Character in 3rd line	Value in 4th line
1	c	Case number
2	n	Evidence number
3	a	Unique description
4	e	Examiner name
5	t	Notes
6	m	Acquisition date and time
7	u	System date and time
8	p	Password hash
9	r	Compression level

For more information see section: Header values

[ASR02] states that the Expert Witness Compression uses 'f', fastest compression.

3.4.2. EnCase 1 (EWF-E01)

Some aspects of this section are:

The header section is defined only once.
It is the first section of the first segment file. It is not found in other segment files.
The header data itself is compressed using zlib.
The end of line character(s) is a carriage return (0x0d) followed by a newline (0x0a).

The 3rd and the 4th line consist of the following tab (0x09) separated values"

Identifier number	Character in 3rd line	Value in 4th line
1	c	Case number
2	n	Evidence number
3	a	Unique description
4	e	Examiner name
5	t	Notes
6	m	Acquisition date and time
7	u	System date and time
8	p	Password hash
9	r	Compression level

For more information see section: Header values

3.4.3. SMART (EWF-S01)

Some aspects of this section are:

The header section is defined once.
It is the first section of the first segment file. It is not found in other segment files.
The header data is always processed by zlib, however the same compression level is used as for the chunks. This could mean compression level 0 which is no compression.

The SMART format uses the FTK Imager (EWF-E01) specification for this section. Note that this could be something FTK Imager specific.

3.4.4. EnCase 2 and 3 (EWF-E01)

Some aspects of this section are:

The same header section defined twice.
It is the first and second section of the first segment file. It is not found in other segment files.
The header data itself is compressed using zlib.
The end of line character(s) is a carriage return (0x0d) followed by a newline (0x0a).

The 3rd and the 4th line consist of the following tab (0x09) separated values:

Identifier number	Character in 3rd line	Value in 4th line
1	c	Case number
2	n	Evidence number
3	a	Unique description
4	e	Examiner name
5	t	Notes
6	av	Version
7	ov	Platform The platform/operating system used to acquire the media
8	m	Acquisition date and time
9	u	System date and time
10	p	Password hash
11	r	Compression level

For more information see section: Header values

3.4.5. EnCase 4 to 7 (EWF-E01)

Some aspects of this section are:

The header is defined only once.
It resides after the header2 sections of the first segment file. It is not found in other segment files.
The header data itself is compressed using zlib.
The end of line character(s) is a carriage return (0x0d) followed by a newline (0x0a).

The 3rd and the 4th line consist of the following tab (0x09) separated values:

Identifier number	Character in 3rd line	Value in 4th line
1	c	Case number
2	n	Evidence number
3	a	Unique description
4	e	Examiner name
5	t	Notes
6	av	Version
7	ov	Platform The platform/operating system used to acquire the media
8	m	Acquisition date and time
9	u	System date and time
10	p	Password hash

For more information see section: Header values

3.4.6. linen 5 to 7 (EWF-E01)

Some aspects of this section are:

The same header section defined twice.
It is the first and second section of the first segment file. It is not found in other segment files.
The header data itself is compressed using zlib.
The end of line character(s) is a newline (0x0a).

The header information consist of 18 lines

The remainder of the string contains the following information:

Line number	Value	Description
1	3	The number of categories provided
2	main	The name/type of the category provided
3		Identifier for the values in the 4th line
4		The data for the different identifiers in the 3rd line
5		(an empty line)
6	srce	The name/type of the section provided See section: Sources category
7
8		Identifier for the values in the section
9
10
11		(an empty line)
12	sub	The name/type of the section provided See section: Subjects category
13
14		Identifier for the values in the section
15
16
17		(an empty line)

The end of line character(s) is a newline (0x0a).

Main category

The 3rd and the 4th line consist of the following tab (0x09) separated values.

Note	The actual values in this category are dependent on the version of linen.

Identifier number	Character in 3rd line	Value in 4th line
1	a	Unique description
2	c	Case number
3	n	Evidence number
4	e	Examiner name
5	t	Notes
6	md	The model of the media, i.e. hard disk model (Introduced in linen 6)
7	sn	The serial number of media (Introduced in linen 6)
8	l	The device label (Introduced in linen 6.19)
9	av	Version
10	ov	Platform The platform/operating system used to acquire the media
11	m	Acquisition date and time
12	u	System date and time
13	p	Password hash
14	pid	Process identifier The identifier of the process memory acquired (Introduced in linen 6.19 or earlier)
15	dc	Unknown (Introduced in linen 6)
16	ext	Extents The extents of the process memory acquired (Introduced in linen 6.19 or earlier)

Note	As of linen 6.19 the acquire date and time is in UTC and the system date and time is in local time. Where as before both values were in local time.

For more information see section: Header values

Sources category

Line 6 the srce category contains information about acquisition sources

TODO describe what a source is in the context of EnCase.

Line 7 consists of 2 values, namely the values are "0 1".

The 8th line consist of the following tab (0x09) separated values.

Identifier number	Character in 8rd line	Meaning
1	p
2	n
3	id	Identifier Contains an integer identifying the source
4	ev	Evidence number Contains a string
5	tb	Total bytes Contains an integer
6	lo	Logical offset Contains an integer which is -1 when value is not set
7	po	Physical offset Contains an integer which is -1 when value is not set
8	ah	Unknown (MD5?) Contains a string
9	sh	Unknown (SHA1?) Contains a string (Introduced in linen 6.19 or earlier)
10	gu	Device GUID Contains a string with a GUID or "0" if not set
11	aq	Acquisition date and time Contains an integer with a POSIX timestamp

Line 9 consists of 2 values, namely the values are "0 0".

Line 10 contains the values defined by line 8.

Note	The default values of some of these values has changed around linen 6.19 or earlier.

Subjects category

Line 12 the sub category contains information about subjects.

TODO describe what a subject is in the context of EnCase.

Line 13 consists of 2 values, namely the values are "0 1".

The 14th line consist of the following tab (0x09) separated values.

Identifier number	Character in 14rd line	Meaning
1	p
2	n
3	id	Identifier Contains an integer identifying the subject
4	nu	Unknown (Number)
5	co	Unknown (Comment)
6	gu	Unknown (GUID)

Line 15 consists of 2 values, namely the values are "0 0".

Line 16 contains the values defined by line 14.

[NOTE] The default values of some of these values has changed around linen 6.19 or earlier.

3.4.7. FTK Imager (EWF-E01)

Some aspects of this section are:

In FTK Imager (EWF-E01) the same header section defined twice.
It is the first and second section of the first segment file. It is not found in other segment files.
The header data itself is compressed using zlib. Note that the compression level can be none and therefore the header looks uncompressed.
In FTK Imager the end of line character(s) is a newline (0x0a).

The 3rd and the 4th line consist of the following tab (0x09) separated values:

Identifier number	Character in 3rd line	Value in 4th line
1	c	Case number
2	n	Evidence number
3	a	Unique description
4	e	Examiner name
5	t	Notes
6	av	Version The FTK Imager version used to acquire the media
7	ov	Platform The platform/operating system used to acquire the media
8	m	Acquisition date and time
9	u	System date and time
10	p	Password hash
11	r	char

For more information see section: Header values

3.4.8. EnCase 5 to 7 (EWF-L01)

The EnCase 4 to 7 (EWF-E01) header section specification is also used for the EnCase 5 to 7 (EWF-L01) format, with the following aspects:

In EnCase 5 both the acquired and system date and time are set to 0.
In EnCase 6 and 7 both the acquired and system date and time are set to Jan 1, 1970 00:00:00 (the time is dependent on the local timezone and daylight savings)

3.4.9. Header values

Identifier	Description	Notes
a	Unique description	Free form string Note that EnCase might not respond when this value is large e.g. >= 1 MiB
c	Case number	Free form string EnCase limits this string to 3000 - 1 characters
n	Evidence number	Free form string EnCase limits this string to 3000 - 1 characters
e	Examiner name	Free form string EnCase limits this string to 3000 - 1 characters
t	Notes	Free form string EnCase limits this string to 3000 - 1 characters
md	Model	Free form string EnCase limits this string to 3000 - 1 characters
sn	Serial Number	Free form string EnCase limits this string to 3000 - 1 characters
l	Device label	Free form string
av	Version	Free form string EnCase limits this string to 12 - 1 characters
ov	Platform	Free form string EnCase limits this string to 24 -1 characters
m	Acquisition date and time	In EnCase: String containing a date and time value E.g. 2002 3 4 10 19 59", which represents March 4, 2002 10:19:59. In linen: String containing POSIX 32-bit epoch timestamp E.g. "1142163845" which represents the date: March 12 2006, 11:44:05
u	Systemdate and time	In EnCase: String containing a date and time value E.g. 2002 3 4 10 19 59", which represents March 4, 2002 10:19:59. In linen: String containing POSIX 32-bit epoch timestamp E.g. "1142163845" which represents the date: March 12 2006, 11:44:05
p	Password hash	String containing the password hash. If no password is set it should be simply the character '0'.
pid	Process identifier	String containing the process identifier (pid) number
dc	Unknown
ext	Extents	extents contains: number of entries entries that consist of: S <1> <2> <3>
r	Compression	Single character that represent the compression level

Note	The restrictions were tested with Encase 7.02.01, older versions could have a restriction of 40 characters instead of 3000 characters.

Character value	Meaning	b
Best compression is used	f	Fastest compression is used

Notes

There should not be a tab, carriage return and newline characters within the text in the 4th line. Or is there a method to escape these characters? [ASR02] states that these characters should not be used in the free form text. Need to confirm this, the specification only speaks of a newline character.

Currently the password has no a additional value than allow an application check it. The data itself is not protected using the password. The password hashing algorithm is unknown. Need to find out. And does the algorithm differ per EnCase version? probably not. The algorithm does not differ in EnCase 1 to 7. FTK Imager does not bother with a password.

3.5. Volume section

The volume section is identified in the section data type field as "volume". Some aspects of this section are:

Defined in the EWF format [ASR02].
Found in EWF-E01 in EnCase 1 to 7 or linen 5 to 7 or FTK Imager, EWF-L01 in EnCase 5 to 7, and SMART (EWF-S01)
Found after the header section of the first segment file. Not found in other segment files.

In the next paragraphs the various versions of the volume section are described.

3.5.1. EWF specification

The specification according to [ASR02].

The additional volume section data is 94 bytes of size and consists of:

Offset	Size	Value	Description
0	4		Reserved according to `[ASR02]` Contains 0x01 Reserved for what?
4	4		The chunk count Contains the number of chunks within the all segment files.
8	4		The number of sectors per chunk Contains 64 per default.
12	4		The number of bytes per sectors Contains 512 per default
16	4		The sectors count, the number of sectors within all segment files
20	20	0x00	Reserved Reserved for what?
40	45	0x00	Padding
85	5		Signature (Reserved) Contains the EWF file header signature
90	4		Checksum Adler-32 of all the previous data within the additional volume section data.

The chunk count is a 32-bit value this means it maximum of addressable chunks would be: 4294967295 (= 2^32 - 1). For a chunk size of 32768 x 4294967295 = about 127 TiB. The maximum segment file amount is 2^16 - 1 = 65535. This allows for an equal number of storage if a segment file is filled to its maximum number of chunks.

However libewf is restricted at 14295 segment files, due to the extension naming schema of the segment files.

3.5.2. SMART (EWF-S01)

The SMART format uses the EWF specification for this section.

In SMART the signature (reverse) value is the string "SMART" (0x53 0x4d 0x41 0x52 0x54) instead of the file header signature.

3.5.3. FTK Imager, EnCase 1 to 7 and linen 5 to 7 (EWF-E01)

The specification for FTK Imager, EnCase 1 to 7 and linen 5 to 7.

The additional volume section data is 1052 bytes of size and consists of:

Offset	Size	Value	Description
0	1		Media type See section: Media type
1	3	0x00	Unknown (empty values)
4	4		The chunk count Contains the number of chunks within the all segment files.
8	4		The number of sectors per chunk (or block size) Contains 64 per default. EnCase 5 is the first version which allows this value to be different than 64.
12	4		The number of bytes per sector
16	8		The sectors count Contains the number of sectors within all segment files This value probably has been changed in EnCase 6 from a 32-bit value to a 64-bit value to support media >2TiB
24	4		The number of cylinders of the C:H:S value Most of the time this value is empty (0x00)
28	4		The number of heads of the C:H:S value Most of the time this value is empty (0x00)
32	4		The number of sectors of the C:H:S value Most of the time this value is empty (0x00)
36	1		Media flags See section: Media flags
37	3	0x00	Unknown (empty values)
40	4		PALM volume start sector
44	4	0x00	Unknown (padding/empty values)
48	4		SMART logs start sector Contains an offset relative from the end of media E.g. a value of 10 would refer to sector = number of sectors - 10
52	1		Compression level (Introduced in EnCase 5) See section: Compression level
53	3	0x00	Unknown (empty values) these values seem to be part of the compression type
56	4		The sector error granularity Contains the error block size (Introduced in EnCase 5)
60	4	0x00	Unknown (empty values)
64	16		Segment file set identifier Contains a GUID/UUID generated on the acquiry system probably used to uniquely identify a set of segment files (Introduced in EnCase 5)
80	963		Unknown (padding/empty values)
1043	5		Signature (Reserved) Contains 0x00
1048	4		Checksum Adler-32 of all the previous data within the additional volume section data.

TODO a value that could be in the volume is the raid stripe size

Note	EnCase requires for media that contains no partition table that the is physical media flag is not set and vice versa. Other tools like FTK check the actual storage media data.

3.5.4. EnCase 5 to 7 (EWF-L01)

The EWF-L01 format uses the EnCase 5 (EWF-E01) volume section specification. However:

the volume type contains 0x0e
the number of chunks is 0
The number of bytes per sectors is some kind of block size value (4096), perhaps the source file system block size
The sectors count, represents some other value because ( sector_size x sector_amount != total_size ) the total size is in the ltree section

3.5.5. Media type

Value	Identifier	Description
0x00		A removable storage media device
0x01		A fixed storage media device

0x03		An optical disc (CD/DVD/BD)

0x0e		Logical Evidence File (LEF or L01)

0x10		Physical Memory (RAM)

Note	FTK imager versions, before version 2.9, set the storage media to fixed (0x01). The exact version of FTK imager where this behavior changed is unknown.

3.5.6. Media flags

Value	Identifier	Description
0x01		Is an image file in FTK Imager, EnCase 1 to 7 this bit is always set, when not set EnCase seems to see the image file as a device
0x02		Is physical device or device type 0 ⇒ a non physical device (logical) 1 ⇒ a physical device
0x04		Fastbloc write blocker used
0x08		Tableau write blocker used This was added in EnCase 6.13

Note	If both the the Fastbloc and Tableau write blocker media flags are set EnCase only shows the Fastbloc.

3.5.7. Compression level

Value	Identifier	Description
0x00		no compression
0x01		good compression
0x02		best compression

3.6. Disk section

The disk section is identified in the section data type field as "disk". Some aspects of this section are:

Not defined in the EWF format [ASR02].
Not found in SMART (EWF-S01).

According to [COH] the disk section is the same as the volume section. This was confirmed with a disk section in an FTK Imager 2.3 (EWF-E01) image.

Note	The disk section was found only in FTK Imager 2.3 when acquiring a physical disk not a floppy. This requires additional research. Is the disk section some old method to differentiate between a partition (volume) image or a physical disk image?

3.7. Data section

The data section is identified in the section data type field as "data". Some aspects of this section are:

It is not defined in the EWF format [ASR02].
Found in EWF-E01 in EnCase 1 to 7 or linen 5 to 7 or FTK Imager, and EWF-L01 in EnCase 5 to 7. Not found in SMART (EWF-S01).
For multiple segment files it does not reside in the first segment file. For a single segment file it does.
Found after the last table2 section in a single segment file or for multiple segment files at the start of the segment files, except for the first.
The data section has data it should should contain the same information as the volume section.

3.7.1. FTK Imager, EnCase 1 to 7 and linen 5 to 7 (EWF-E01)

The additional data section data is 1052 bytes of size and consists of:

Offset	Size	Value	Description
0	1		Media type See section: Media type
1	3	0x00	Unknown (empty values)
4	4		The chunk count Contains the number of chunks within the all segment files.
8	4		The block size (number of sectors per chunk) Contains 64 per default. EnCase 5 is the first version which allows this value to be different than 64.
12	4		The number of bytes per sector
16	8		The sectors count Contains the number of sectors within all segment files This value probably has been changed in EnCase 6 from a 32-bit value to a 64-bit value to support media >2TiB
24	4		The number of cylinders of the C:H:S value Most of the time this value is empty (0x00)
28	4		The number of heads of the C:H:S value Most of the time this value is empty (0x00)
32	4		The number of sectors of the C:H:S value Most of the time this value is empty (0x00)
36	1		Media flags See section: Media flags
37	3	0x00	Unknown (empty values)
40	4		PALM volume start sector
44	4	0x00	Unknown (padding/empty values)
48	4		SMART logs start sector Contains an offset relative from the end of media E.g. a value of 10 would refer to sector = number of sectors - 10
52	1		Compression level (Introduced in EnCase 5) See section: Compression level
53	3	0x00	Unknown (empty values) These values seem to be part of the compression type
56	4		The sector error granularity Contains the error block size (Introduced in EnCase 5)
60	4	0x00	Unknown (empty values)
64	16		Segment file set identifier Contains a GUID/UUID generated on the acquiry system probably used to uniquely identify a set of segment files (Introduced in EnCase 5)
80	963		Unknown (padding/empty values)
1043	5		Signature (Reserved) Contains 0x00
1048	4		Checksum Adler-32 of all the previous data within the additional data section data.

Note	In Logicube products (Talon (firmware predating April 2013) and Forensic dossier (before version 3.3.3RC16)) the checksum is not calculated and set to 0.

3.7.2. EnCase 5 to 7 (EWF-L01)

The EWF-L01 format uses the EnCase 5 (EWF-E01) data section specification. However:

the data type contains 0x0e
the number of chunks is 0
The number of bytes per sectors is some kind of block size value (4096), perhaps the source file system block size
The sectors count, represents some other value because ( sector_size x sector_amount != total_size ) the total size is in the ltree section

3.8. Sectors section

The sectors section is identified in the section data type field as "sectors". Some aspects of this section are:

Not defined in the EWF format [ASR02].
Found in EWF-E01 in EnCase 2 to 7, or linen 5 to 7 or FTK Imager, EWF-L01 in EnCase 5 to 7. Not found in EnCase 1 (EWF-E01) or SMART (EWF-S01).
The first sectors section can be found after the volume section in the first segment file or at the after the data section in other segment files. Successive sector data sections are found after the sector table2 section.

The sectors section contains the actual chunks of media data.

The sectors section can contain multiple chunks.
The default size of a chunk is 32768 bytes of data (64 standard sectors, with a size of 512 bytes per sector). It is possible in EnCase 5 and 6 and linen 5 and 6 to change the number of sectors per block to 64, 128, 256, 1024, 2048, 4096, 8192, 16384 or 32768. In EnCase 7 and linen 7 this has been reduced to 64, 128, 256, 1024.

3.8.1. Data chunk

The first chunk is often located directly after the section descriptor, although the format does not require this.

When the data is compressed and the compressed data (with checksum) is larger than the uncompressed data (without the checksum) the data chunk is stored uncompressed. The default size of a chunk is 32768 bytes of data (64 standard sectors).

An uncompressed data chunk is variable of size and consists of:

Offset	Size	Value	Description
0	…		Uncompressed chunk data
…	4		Checksum Adler-32 of the chunk data

The compressed data chunk consist of zlib compressed data. The checksum of the compressed data chunk is part the zlib compressed data format. See section: Compression.

3.8.2. Optical disc images

For a MODE‑1 CD-ROM optical disc image EnCase only seems to support 2048 bytes per sector (the data).

The raw sector size of a MODE-1 CD-ROM is 2352 bytes of size and consists of:

Offset	Size	Description
0	16	Synchronization bytes
16	2048	Data
2054	4	Error detection
2058	8	Unknown (Empty values)
2066	276	Error correction

TODO add information about Mode-2 and Mode-XA

3.9. Table section

The table section is identified in the section data type field as "table". Some aspects of this section are:

Defined in the EWF format [ASR02].
Found in EWF-E01 in EnCase 1 to 7 or linen 5 to 7 or FTK Imager, EWF-L01 in EnCase 5 to 7, and SMART (EWF-S01)

Note	The offsets within the section descriptor are 8 bytes (64 bits) of size while the offsets in the table entry array are 4 bytes (32 bits) of size.

In the next paragraphs the various versions of the table section are described.

3.9.1. EWF specification

Some aspects of the table section according to the EWF specification are:

The first table section resides after the volume section in the first segment file or after the file header in other segment files.
It can be found in every segment file.

The table section consists of:

the table header
an array of table entries
the data chunks

Table header

The table header is 24 bytes of size and consists of:

Offset	Size	Value	Description
0	4		The number of entries Note that according to `[ASR02]` it contains 0x01
4	16	0x00	Padding
20	4		Checksum Adler-32 of all the previous data within the additional volume section data.

According to [ASR02] the table can hold 16375 entries if more entries are required an additional table section should be created.

Table entry

The table entry is 4 bytes of size and consists of:

Offset	Size	Value	Description
0	4		Chunk data offset

The most significant bit (MSB) in the chunk data offset indicates if the chunk is compressed (1) or uncompressed (0).

A chunk data offset points to the start of the chunk of media data, which resides in the same table section within the segment file. The offset contains a value relative to the start of the file.

Data chunk

The first chunk is often located directly after the last table entry, although the format does not require this.

A data chunk is always compressed even when no compression is required. This approach provides a checksum for each chunk. The default size of a chunk is 32768 bytes of data (64 standard sectors). The resulting size of the "compressed" chunk can therefore be larger than the default chunk size. This however was deducted from the behavior of FTK Imager for EWF-S01.

The compressed data chunk consist of zlib compressed data. The checksum of the compressed data chunk is part the zlib compressed data format. See section: Compression.

3.9.2. SMART (EWF-S01)

The table section in the SMART (EWF-S01) format is equivalent to that of the EWF specification.

3.9.3. EnCase 1 (EWF-E01)

Some aspects of this section are:

The table section resides after the volume section in the first segment file or after the file header in other segment files.
It can be found in every segment file.

The table section consists of:

the table header
an array of table entries
the table footer
the data chunks

Table header

The table header is 24 bytes of size and consists of:

Offset	Size	Value	Description
0	4		The number of entries
4	16	0x00	Padding
20	4		Checksum Adler-32 of all the previous data within the additional volume section data.

The table can hold 16375 entries if more entries are required an additional table section should be created.

Table entry

The table entry is 4 bytes of size and consists of:

Offset	Size	Value	Description
0	4		Chunk data offset

The most significant bit (MSB) in the chunk data offset indicates if the chunk is compressed (1) or uncompressed (0).

A chunk data offset points to the start of the chunk of media data, which resides in the same table section within the segment file. The offset contains a value relative to the start of the file.

Table footer

The table footer is 4 bytes of size and consists of:

Offset	Size	Value	Description
0	4		Checksum Adler-32 of the offset array

Data chunk

The first chunk is often located directly after the table footer, although the format does not require this.

When the data is compressed and the compressed data (with checksum) is larger than the uncompressed data (without the checksum) the data chunk is stored uncompressed. The default size of a chunk is 32768 bytes of data (64 standard sectors).

An uncompressed data chunk is variable of size and consists of:

Offset	Size	Value	Description
0	…		Uncompressed chunk data
…	4		Checksum Adler-32 of the chunk data

The compressed data chunk consist of zlib compressed data. The checksum of the compressed data chunk is part the zlib compressed data format. See section: Compression

3.9.4. FTK Imager and EnCase 2 to 5 and linen 5 (EWF-E01)

Some aspects of this section are:

The table section resides after the sectors section.
It can be found in every segment file.
The data chunks are no longer stored in this section but in the sectors section instead.
The table2 section contains a mirror copy of the table section. In EWF-E01 it is always present.

The table section consists of:

the table header
an array of table entries
the table footer

Table header

The sector table header is 24 bytes of size and consists of:

Offset	Size	Value	Description
0	4		The number of entries
4	16	0x00	Padding
20	4		Checksum Adler-32 of all the previous data within the additional volume section data.

The table section can hold 16375 entries. A new table section should be created to hold more entries. Both FTK Imager and EnCase 5 can handle more than 16375, FTK 1 cannot. To contain more than 16375 chunks new sectors, table and table2 sections need to be created after the table2 section.

Table entry

The table entry is 4 bytes of size and consists of:

Offset	Size	Value	Description
0	4		Chunk data offset

The most significant bit (MSB) in the chunk data offset indicates if the chunk is compressed (1) or uncompressed (0).

A chunk data offset points to the start of the chunk of media data, which resides in the preceding sectors section within the segment file. The offset contains a value relative to the start of the file.

Table footer

The table footer is 4 bytes of size and consists of:

Offset	Size	Value	Description
0	4		Checksum Adler-32 of the offset array

3.9.5. EnCase 6 to 7 and linen 6 to 7 (EWF-E01)

Some aspects of this section are:

Every segment file contains its own table section.
It resides after the sectors section.
The data chunks are no longer stored in this section but in the sectors section instead.
The table2 section contains a mirror copy of the table section. In EWF-E01 it is always present.

The table section consists of:

the table header
an array of table entries
the table footer

Table header

The sector table header is 24 bytes of size and consists of:

Offset	Size	Value	Description
0	4		The number of entries
4	4	0x00	Padding
8	8		The table base offset
16	4	0x00	Padding
20	4		Checksum Adler-32 of all the previous data within the additional volume section data.

As of EnCase 6 the number of entries is no longer restricted to 16375 entries. The new limit seems to be 65534.

Table entry

The table entry is 4 bytes of size and consists of:

Offset	Size	Value	Description
0	4		Chunk data offset

The most significant bit (MSB) in the chunk data offset indicates if the chunk is compressed (1) or uncompressed (0).

A chunk data offset points to the start of the chunk of media data, which resides in the preceding sectors section within the segment file. The offset contains a value relative to the table base offset.

In EnCase 6.7.1 the sectors section can be larger than 2048Mb. The table entries offsets are 31 bit values in EnCase6 the offset in a table entry value will actually use the full 32 bit if the 2048Mb has been exceeded. This behavior is no longer present in EnCase 6.8 so it is assumed to be a bug. Libewf currently assumes that the if the 31 bit value overflows the following chunks are uncompressed. This allows EnCase 6.7.1 faulty EWF files to be converted by libewf.

Table footer

The table footer is 4 bytes of size and consists of:

Offset	Size	Value	Description
0	4		Checksum Adler-32 of the offset array

3.9.6. EnCase 6 to 7 (EWF-L01)

The EWF-L01 format uses the EnCase 6 to 7 (EWF-E01) table section specification.

3.10. Table2 section

The table2 section is identified in the section data type field as "table2". Some aspects of this section are:

Not defined in the EWF format [ASR02].
Found in EWF-E01 in EnCase 2 to 7, or linen 5 to 7 or FTK Imager, EWF-L01 in EnCase 5 to 7. Not found in EnCase 1 (EWF-E01) or SMART (EWF-S01).
Uses the same format as the table section.
Resides directly after the table section.

3.10.1. FTK Imager and EnCase 2 to 7 and linen 5 to 7 (EWF-E01)

The table2 section contains a mirror copy of the table section. Probably intended for recovery purposes.

3.10.2. EnCase 5 to 7 (EWF-L01)

The EWF-L01 format uses the EWF-E01 table2 section specification.

3.11. Next section

The next section is identified in the section data type field as "next". Some aspects of this section are:

Defined in the EWF format [ASR02].
Found in EWF-E01 in EnCase 1 to 7 or linen 5 to 7 or FTK Imager, EWF-L01 in EnCase 5 to 7, and SMART (EWF-S01)
The last section within a segment other than the last segment file.
The offset to the next section in the section descriptor of the next section point to itself (the start of the next section).
It should be the last section in a segment file, other than the last segment file.

3.11.1. SMART (EWF-S01)

It resides after the table or table2 section.

3.11.2. FTK Imager, EnCase and linen (EWF-E01)

It resides after the data section in a single segment file or for multiple segment files after the table2 section.

In the EnCase (EWF-E01) format the size in the section descriptor is 0 instead of 76 (the size of the section descriptor).

Note	FTK imager versions before 2.9 sets the section size to 76. At the moment it is unknown in which version this behavior was changed.

3.12. Ltypes section

The ltypes section is identifier in the section data type field as "ltypes". Some aspects of this section are:

Found in EWF-L01 in of EnCase 7
Found in the last segment file after table2 section before tree section.

The additional ltypes section data is 6 bytes of size and consists of:

Offset	Size	Description
0	2	Unknown
2	2	Unknown
4	2	Unknown

3.13. Ltree section

The ltree section is identifier in the section data type field as "ltree". Some aspects of this section are:

Found in EWF-L01 in of EnCase 5 to 7
Found in the last segment file after ltypes section and before data section.

The ltree section consists of:

ltree header
ltree data

3.13.1. Ltree header

The ltree header is 48 bytes of size and consists of:

Offset	Size	Description
0	16	Integrity hash Contains the MD5 of the ltree data
16	8	Data size
24	4	Checksum Adler-32 of all the data within the ltree header where the checksum value itself is zeroed out.
28	20	Unknown (empty values)

3.13.2. Ltree data

The ltree data string consists of an UTF-16 little-endian encoded string without byte order mark. The ltree data is not strict UTF-16 since it allows for unpaired surrogates, such as "U+d800" and "U+dc00".

Other observed characteristics where the names in the ltree deviate from the original source:

[U+0001-U+0008] were converted to U+00ba
[U+0009, U+000a] were stripped
[U+000b, U+000c] were converted to U+0020
U+000d was converted to U+0002
U+00ba remained the same

Note that this behavior could be related to Encase as well and might not be specific for EWF-L01.

The ltree data string contains the following information:

Line number	Value	Description
1	5	The number of categories provided
2	rec	Information about unknown See section: Records category
…		(an empty line)
…	perm	Information about file permissions See section: Permissions category
…		(an empty line)
…	srce	Information about acquisition sources See section: Sources category
…		(an empty line)
…	sub	Information about unknown See section: Subjects category
…		(an empty line)
…	entry	Information about file entries See section: File entries category
…		(an empty line)

The end of line character(s) is a newline (0x0a).

3.13.3. Records category

The rec category contains information about records.

The 1st line of the category contains the string "rec".

The 2nd line of the category contains tab (0x09) separated type indicators.

Identifier number	Type indicator	Description
1	tb	Total bytes Contains an integer with size of the logical file data (media data)
2	cl	Unknown (Clusters?)
3	n	Unknown (introduced in EnCase 6.19)
4	fp	Unknown (introduced in EnCase 7)
5	pg	Unknown (introduced in EnCase 7)
6	lg	Unknown (introduced in EnCase 7)
7	ig	Unknown (introduced in EnCase 7)

The 3rd line of the category consist of the tab (0x09) separated values.

3.13.4. Permissions category

The perm category contains information about file permissions.

The 1st line of the category contains the string "perm".

The 2nd line consists of the following 2 values:

Value number	Value	Description
1		The number of permission groups in the category
2	1	Unknown

The 3rd line of the category contains tab (0x09) separated type indicators. For more information see the sections below.

The remaining lines in the category consist of:

category root entry
zero or more permissions group entries
zero or more permission entries

Each entry consist of 2 lines:

Line number	Value	Description
1		Number of entries
2		Tab (0x09) separated values that correspond to the type indicators.

The 1st line of the category root entry consists of the following 2 values:

Value number	Value	Description
1	0	Unknown
2		The number of permission groups in the category

The 1st line of the permission group entry consists of the following 2 values:

Value number	Value	Description
1	0	Unknown
2		The number of permissions in the group

The 1st line of the permission entry consists of the following 2 values:

Value number	Value	Description
1	0	Unknown
2	0	Unknown

Permission type indicators

Identifier number	Type indicator	Description
1	p	Is parent 1 ⇒ if the entry is a category root or permissions group 0 ⇒ if the entry is a permission
2	n	Name Contains a string
3	s	Security identifier Contains a string with either a Windows NT security identifier (SID) or a POSIX user (uid) or group identifier (gid) in the format " number:" such as " 99:"
4	pr	Property type See section: Permission types
5	nta	Access mask
6	nti	Unknown (Windows NT access control entry (ACE) flags?) Contains an integer with a Windows NT access control entry (ACE) flags Seen 0x10, which presubly corresponds with INHERITED_ACE?
7	nts	Unknown (Permission?) (Removed in EnCase 6)

Permission types

Value	Identifier	Description
(empty)		Owner or category root
1		Group
2		Allow

6		Other

10		Unknown (permissions group?)

Access mask

Access mask seen in combination with property types 0, 1 and 6

Value	Identifier	Description
(empty)		Owner or category root
0x00000001	`[Lst Fldr/Rd Data]`	List folder / Read data
0x00000002	`[Crt Fl/W Data]`	Create file / Write data

0x00000020	`[Trav Fldr/X Fl]`	Traverse folder / Execute file

Access mask seen in combination with property type 2

[0x001200a9] [R&X] [R] [Sync]
[0x001301bf] [M] [R&X] [R] [W] [Sync]
[0x001f01ff] [FC] [M] [R&X] [R] [W] [Sync]

Value	Identifier	Description
(empty)		Owner or category root
0x00000001
0x00000002
0x00000004
0x00000008
0x00000010
0x00000020
0x00000040
0x00000080
0x00000100

0x00010000
0x00020000
0x00040000
0x00080000
0x00100000

3.13.5. Sources category

The srce category contains information about acquisition sources of the file entries.

TODO describe what an acquisition source is in the context of EnCase.

The 1st line of the category contains the string "srce".

The 2nd line consists of 2 values.

Value index	Value	Description
1		The number of sources in the category
2	1	Unknown

The 3rd line of the category contains tab (0x09) separated type indicators. For more information see the sections below.

The remaining lines in the category consist of:

category root
zero or more source entries

Each entry consist of 2 lines:

Line number	Value	Description
1		Number of entries
2		Tab (0x09) separated values that correspond to the type indicators.

The 1st line of the category root entry consists of the following 2 values:

Value number	Value	Description
1	0	Unknown
2		The number of sources in the category

The 1st line of the source entry consists of the following 2 values:

Value number	Value	Description
1	0	Unknown
2	0	Unknown

Source type indicators

Identifier number	Type indicator	Description
1	p
2	n
3	id	Identifier Contains an integer identifying the source
4	ev	Evidence number Contains a string
5	do	Domain Contains a string (introduced in EnCase 7.9)
6	loc	Location Contains a string (introduced in EnCase 7.9)
7	se	Serial number Contains a string (introduced in EnCase 7.9)
8	mfr	Manufacturer Contains a string (introduced in EnCase 7.9)
9	mo	Model Contains a string (introduced in EnCase 7.9)
10	tb	Total bytes Contains an integer
11	lo	Logical offset Contains an integer which is -1 when value is not set
12	po	Physical offset Contains an integer which is -1 when value is not set
13	ah	MD5 hash Contains a string with the MD5 hash of the source
14	sh	SHA1 hash Contains a string with the SHA1 hash of the source (introduced in EnCase 6.19)
15	gu	Device GUID Contains a string with a GUID or "0" if not set
16	pgu	Primary device GUID Contains a string with a GUID or "0" if not set (introduced in EnCase 7)
17	aq	Acquisition date and time Contains an integer with a POSIX timestamp
18	ip	IP address Contains a string (introduced in EnCase 7.9)
19	si	Unknown (Static IP address?) Contains 1 if static, empty otherwise (introduced in EnCase 7.9)
20	ma	MAC address Contains a string without separator characters (introduced in EnCase 7.9)
21	dt	Drive type Contains a character (introduced in EnCase 7.9)

The acquisition date and time is in the form of: "1142163845", which is a POSIX epoch timestamp and represents the date: March 12 2006, 11:44:05.

If the "ha" value contains "00000000000000000000000000000000" this means the MD5 hash is not set. The same applies for the "sha" value when it contains "0000000000000000000000000000000000000000" the SHA1 has is not set.

If the "ma" value contains "000000000000" this means the MAC address is not set.

Drive type

Character value	Meaning	f

3.13.6. Subjects category

The sub category contains information about TODO

TODO describe what a subject is in the context of EnCase.

The 1st line of the category contains the string "sub".

The 2nd line consists of 2 values.

Value index	Value	Description
1		The number of subjects in the category
2	1	Unknown

The 3rd line of the category contains tab (0x09) separated type indicators. For more information see the sections below.

The remaining lines in the category consist of:

category root
zero or more subject entries

Each entry consist of 2 lines:

Line number	Value	Description
1		Number of entries
2		Tab (0x09) separated values that correspond to the type indicators.

The 1st line of the category root entry consists of the following 2 values:

Value number	Value	Description
1	0	Unknown
2		The number of subject in the category

The 1st line of the subject entry consists of the following 2 values:

Value number	Value	Description
1	0	Unknown
2	0	Unknown

Subject type indicators

Identifier number	Type indicator	Description
1	p
2	n
3	id	Identifier Contains an integer identifying the subject
4	nu	Unknown (Number)
5	co	Unknown (Comment)
6	gu	Unknown (GUID)

3.13.7. File entries category

The entry category contains information about the file entries.

The 1st line of the category contains the string "entry".

The 2nd line consists of 2 values.

Value index	Value	Description
1		The number of file entries in the category or 1 if unknown
2	1	Unknown

The 3rd line of the category contains tab (0x09) separated type indicators. For more information see the sections below.

The remaining lines in the category consist of:

category root
zero or more file entries
zero or more sub file entries
…

Each entry consist of 2 lines:

Line number	Value	Description
1		Number of entries
2		Tab (0x09) separated values that correspond to the type indicators.

The 1st line of the category root entry consists of the following 2 values:

Value number	Value	Description
1		0 if not set or 26 if Unknown
2		The number of file entries in the category

The 1st line of the file entry consists of the following 2 values:

Value number	Value	Description
1		Number of file entries in the parent file entry or 0 if not set
2		The number of sub file entries in the file entry

EnCase 5 and 6 (EWF-L01) file entry type indicators

Identifier number	Character in 29th line	Meaning
1	p	Is parent 1 ⇒ if the entry is a directory (empty) ⇒ if the entry is a file
2	n	Name See section: File entry name
3	id	Identifier Contains an integer identifying the file entry
4	opr	Flags See section: File entry flags
5	src	Source identifier Contains an integer that corresponds to an identifier in the Sources category
6	sub	Subject identifier Contains an integer that corresponds to an identifier in the Subjects category
7	cid	Unknown (record type)
8	jq	Unknown
9	cr	Creation date and time
10	ac	Access date and time (precision is date only)
11	wr	(File) modification (last written) date and time
12	mo	(File system) entry modification date and time
13	dl	Deletion date and time
14	aq	Acquisition date and time Contains an integer with a POSIX timestamp
15	ha	MD5 hash Contains a string with the MD5 hash of the file data
16	ls	File size The file size specified in bytes If the file size is 0 the data size should be 1
17	du	Duplicate data offset Relative from the start of the media data
18	lo	Logical offset Contains an integer which is -1 when value is not set
19	po	Physical offset Contains an integer which is -1 when value is not set The segment file in which the start of the data is stored, -1 for a single segment file ?
20	mid	GUID Contains a string with a GUID (introduced in EnCase 6.19)
21	cfi	Unknown (introduced in EnCase 6.14)
22	be	Binary extents See section: Binary extents value
23	pm	Permissions group index Contains an integer that corresponds to an identifier in the Permissions category or -1 if not set The value is 0 by default
24	lpt	Unknown (introduced in EnCase 6.19)

The creation, access and last written date and time are in the form of: "1142163845", which is a POSIX epoch timestamp and represents the date: March 12 2006, 11:44:05.

The "ha" value (Hash) consist of a MD5 hash string when file entries are hashed. If the "ha" value contains "00000000000000000000000000000000" this means the MD5 hash is not set.

Ltree file entries

The ltree entries of files and directories consist of entries starting with: 0 followed by the number of sub file entries.

The entries of files and directories:

Line number	Value	Description
1	(empty)	The root directory
2		The target drive/mount point
3		The actual single file entries

EnCase 7 (EWF-L01) file entry type indicators

Identifier number	Character in 29th line	Meaning
1	mid	GUID Contains a string with a GUID
2	ls	File size The file size specified in bytes If the file size is 0 the data size should be 1
3	be	Binary extents See section: Binary extents value
4	id	Identifier Contains an integer identifying the file entry
5	cr	Creation date and time
6	ac	Access date and time
7	wr	(File) modification (last written) date and time
8	mo	(File system) entry modification date and time
9	dl	Deletion date and time
10	sig	Unknown (Introduced in EnCase 7)
11	ha	MD5 hash Contains a string with the MD5 hash of the file data
12	sha	SHA1 hash Judging by the size this value is assumed to be the SHA1 hash of the file data, does not seem to be currently set by EnCase (Introduced in EnCase 7)
13	ent	Unknown Seen: 'B' (Introduced in EnCase 7.9)
14	snh	Short (or DOS 8.3) name See section: Short name (Introduced in EnCase 7.9)
15	p	Is parent 1 ⇒ if the entry is a directory (empty) ⇒ if the entry is a file
16	n	Name See section: File entry name
17	du	Duplicate data offset Relative from the start of the media data
18	lo	Logical offset Contains an integer which is -1 when value is not set
19	po	Physical offset Contains an integer which is -1 when value is not set The segment file in which the start of the data is stored, -1 for a single segment file ?
20	pm	Permissions group index Contains an integer that corresponds to an identifier in the Permissions category or -1 if not set The value is 0 by default
21	oes	Unknown (Original extents) (Introduced in EnCase 7)
22	opr	Flags See section: File entry flags
23	src	Source identifier Contains an integer that corresponds to an identifier in the Sources category
24	sub	Subject identifier Contains an integer that corresponds to an identifier in the Subjects category
25	cid	Unknown (record type)
26	jq	Unknown
27	alt	Unknown (Introduced in EnCase 7)
28	ep	Unknown (Introduced in EnCase 7)
29	aq	Acquisition date and time Contains an integer with a POSIX timestamp
30	cfi	Unknown
31	sg	Unknown (Introduced in EnCase 7)
32	ea	Extended attributes See section: Extended attributes value (Introduced in EnCase 7.9)
33	lpt	Unknown

If the "ha" value contains "00000000000000000000000000000000" this means the MD5 hash is not set. The same applies for the "sha" value when it contains "0000000000000000000000000000000000000000" the SHA1 has is not set.

File entry name

A file entry name ("n" value):

can contain path segment separator characters like "\\" and "/"
uses the "MIDDLE DOT" Unicode character (U+00b7) as a (NTFS) alternative data stream (ADS) name seperator

Note	Note that a regular "MIDDLE DOT" Unicode character will be encoded in the same way so no real way to reliably tell the difference.

An empty name has been observed to be represented as "NoName".

Short name

The short name ("snh") value contains 2 values:

Value number	Value	Description
1		The number of characters in the short name including the end-of-string character
2		The short name string The string does not include the end-of-string character

For example: "13 FILE10~1.TXT"

Original extents

TODO: add some text

1 30a555b 30a6000 12011ae00 9008d7 3f 43 1 12011ae00 30a6000 120113 30a6 9008d7 18530

Ltree file entries

The ltree entries of files and directories consist of entries starting with: 26 followed by the number of sub file entries.

The entries of files and directories:

Line number	Value	Description
1	LogicalEntries	The root directory
2		The target drive/mount point
3		The actual single file entries

File entry flags

Value	Identifier	Description
0x00000001		Unknown (Is read-only?)
0x00000002	Hidden	Is hidden
0x00000004	System	Is system
0x00000008	Archive	Is archive
0x00000010	Sym Link	Is symbolic link, junction or reparse point

0x00000080	Deleted	Is deleted

0x00001000	Hard Linked	Is hard link
0x00002000	Stream	Is stream

0x00100000	Internal	Is internal (used in combination with 0x00000006?)

0x00200000	Unallocated Clusters	Unknown
0x00400000		Unknown

0x01000000		Unknown
0x02000000	Folder	Is folder
0x04000000		Data is sparse See remarks below.

If 0x00002000 or 0x02000000 are not set the file entry is of type "File".

If the sparse data flag is set:

the data size should be 1 and data should consist of a single byte value.
the data size should be equal to the file size and data should be the same.

If the duplicate data offset value is not set the single byte value in the data should be used to reconstruct the file data. E.g. if the file size is 4096 and the data contains the byte value 0x00 the resulting file should consists of 4096 x 0x00 byte values.

If the duplicate data offset value is set the single byte in the data is ignored and the duplicate data offset refers to the location where the data stored.

Binary extents value

The binary extents value contains 3 values separated by a space:

Unknown Offset Size

Where:

unknown always is 1 (could this be the number of extents?)
extent data offset, relative from the start of the media data
extent data size

The offset and size are specified in hexadecimal values.

Note: Contains 1 value for the first single file entry.

Extended attributes value

The extended attributes value contains base-16 encoded data, which consists of:

Extended attributes header (stored as an extended attribute)
One or more extended attributes

Extended attributes header

The extended attributes header is 37 bytes of size and consists of:

Offset	Size	Value	Description
0	4	0	Unknown (0 ⇒ root, 1 ⇒ otherwise)
4	1	1	Unknown (0 ⇒ is leaf node, 1 ⇒ is branch node?)
5	4	11	Number of characters in name string including the end-of-string character
9	4	1	Number of characters in value string including the end-of-string character
13	22	"Attributes\0"	Name string Contains an UTF-16 little-endian encoded string including end-of-string character
35	2	"\0"	Value string Contains an UTF-16 little-endian encoded string including end-of-string character

Extended attribute

An extended attributes is variable of size and consists of:

Offset	Size	Description
0	4	Unknown (0 ⇒ root, 1 ⇒ otherwise)
4	1	Unknown (0 ⇒ is leaf node, 1 ⇒ is branch node?)
5	4	Number of characters in name string including the end-of-string character
9	4	Number of characters in value string including the end-of-string character
13	…	Name string Contains an UTF-16 little-endian encoded string including end-of-string character
…	…	Value string Contains an UTF-16 little-endian encoded string including end-of-string character

TODO: complete section

Note	Branch nodes are presuably used to group attributes, however these are not used consistently and are not shown by Encase 7.

3.14. Map section

Some aspects of this section are:

Found in EWF-L01 in of EnCase 7 (First seen in EnCase 7.4.1.10)
Found in the last segment file after data section before done section.

The map consists of:

map string
map entries array

3.14.1. Map string

The map string consists of an UTF-16 little-endian encoded string without the UTF-16 endian byte order mark.

The map string contains the following information:

Line number	Value	Description
1	1	The number of categories provided
2	r	Probably the type of information provided
3	c	Identifier for the values in the 4th line
4		The data for the different identifiers in the 3rd line
5		(an empty line)

Map string values

Identifier number	Character in 29th line	Meaning
1	C	Number of map entries (count)

The number of map entries should match the number of file entries in the ltree.

3.14.2. Map entry

A map entry is 24 bytes of size and consists of:

Offset	Size	Description
0	4	Unknown
4	4	Unknown (empty values or part of previous value)
8	16	Unknown

3.15. Session section

The session section is identifier in the section data type field as "session". Some aspects of this section are:

It is not defined in the EWF format [ASR02].
It is not found in SMART (EWF-S01) and FTK Imager (EWF-E01).
It is found in EnCase 5 and 6 (EWF-E01) files.
It is only added to the last segment file for images of optical disc (CD/DVD/BD) media.
It is found after the data section and before the error2 section.

The session section data consists of:

The session header
The session entries array
The session footer

3.15.1. Session header

The session header is 36 byte of size and consists of:

Offset	Size	Description
0	4	Number of sessions
4	28	Unknown (empty values)
32	4	Checksum Adler-32 of all the previous data within the additional session section data.

3.15.2. Session entry

A session entry is 32 byte of size and consists of:

Offset	Size	Description
0	4	Flags
4	4	Start sector
8	24	Unknown (empty values)

EnCase stores audio tracks as 0 byte data with a sector size of 2048.

Note	For a CD the first session sector is stored as 16, although the actual session starts at sector 0. Could this value be overloaded to indicate the size of the reserved space between the start of the session and the ISO 9660 volume descriptor.

3.15.3. Session flags

Value	Identifier	Description
0x00000001		If set the track is an audio track otherwise the track is a data track

3.15.4. Session footer

The session footer is 4 byte of size and consists of:

Offset	Size	Value	Description
0	4		Checksum Adler-32 of all the data within the session entries array

3.16. Error2 section

The error2 section is identifier in the section data type field as "error2". Some aspects of this section are:

It is not defined in the EWF format [ASR02].
It is not found in SMART (EWF-S01).
It is found in, EnCase 3 to 7 and linen 5 to 7 (EWF-E01) files.
It is only added to the last segment file when errors were encountered while reading the input.

TODO check FTK Imager, EnCase 1 and 2 for presence of the error2 section.

It contains the sectors that have read errors. The sector where a read error occurred are filled with zero’s during acquiry by EnCase.

The error2 section data consists of:

The error2 header
The error2 entries array
The error2 footer

3.16.1. Error2 header

The error2 header is 520 byte of size and consists of:

Offset	Size	Description
0	4	Number of entries
4	512	Unknown (empty values)
516	4	Checksum Adler-32 of all the previous data within the error2 header data.

3.16.2. Error2 entry

An error2 entry is 8 byte of size and consists of:

Offset	Size	Value	Description
0	4		Start sector
4	4		The number of sectors

3.16.3. Error2 footer

The error2 footer is 4 byte of size and consists of:

Offset	Size	Value	Description
0	4		Checksum Adler-32 of all the data within the error2 entries array

3.17. Digest section

The digest section is identified in the section data type field as "digest". Some aspects of this section are:

It is found in EnCase 6 to 7 files, as of EnCase 6.12 and linen 6.12 (EWF-E01).

The digest section contains a MD5 and/or SHA1 hash of the data within the chunks.

The additional digest section data is 80 byte of size and consists of:

Offset	Size	Value	Description
0	16		MD5 hash of the media data
16	20		SHA1 hash of the media data
36	40	0x00	Padding
76	4		Checksum Adler-32 of all the previous data within the additional digest section data.

3.18. Hash section

The hash section is identified in the section data type field as "hash". Some aspects of this section are:

It is defined in the EWF format [ASR02].
It is found in SMART (EWF-S01) and FTK Imager, EnCase 1 to 7 and linen 5 to 7 (EWF-E01) files.
It is not found in EnCase 5 (EWF-L01).
The hash section is optional, it does not need to be present. If it does it resides in the last segment file before the done section.

The hash section contains a MD5 hash of the data within the chunks.

The additional digest section data is 36 byte of size and consists of:

Offset	Size	Description
0	16	MD5 hash of the media data
16	16	Unknown
32	4	Checksum Adler-32 of all the previous data within the additional hash section data.

3.18.1. Notes

Observations regarding the unknown value:

is zero in SMART
is zero in EnCase 3 and below
in EnCase 4 the first 4 bytes are 0, the next 8 bytes seem random, the last 4 bytes seem fixed
in EnCase 5 and 6 the first 8 bytes seem random, the last 8 bytes equal the file header signature
in linen 5 the first and last set of 4 bytes seem the same, the second set of 4 bytes seem to be random, the third set of 4 bytes seem to contain a piece of the file header signature
in linen 6 the first and third set of 4 bytes seem random, the second and last set of 4 bytes seem to be the same
EnCase5 seems to contain a GUID of the acquired device?

Test with EnCase 4 show that:

The value does not equal the checksum of the media data
Does not differentiate for the same media acquired within the same program session, using different formats, but differ for different media and different program sessions

3.19. Done section

The done section is identified in the section data type field as "done". Some aspects of this section are:

It is defined in the EWF format [ASR02].
It is found in SMART (EWF-S01), FTK Imager, EnCase 1 to 7 and linen 5 to 7 (EWF-E01) and EnCase 5 (EWF-L01) files.
The done section is the last section within the last segment file.
The offset to the next section in the section descriptor of the done section point to itself (the start of the done section).
It should be the last section in the last segment file.

3.19.1. SMART (EWF-S01)

It resides after the table or table2 section.

3.19.2. FTK Imager, EnCase and linen (EWF-E01)

It resides after the data section in a single segment file or for multiple segment files after the table2 section.

In the EnCase (EWF-E01) format the size in the section descriptor is 0 instead of 76 (the size of the section descriptor).

Note	FTK imager versions before 2.9 sets the section size to 76. At the moment it is unknown in which version this behavior was changed.

3.19.3. Incomplete section

The incomplete section is identified in the section data type field as "incomplete".

This section is seen rarely. It was seen in an EnCase 6.13 (EWF-E01) file as the last last section within the last segment file. The incomplete section was preceded by a hash and digest section, although later in the set of EWF files another hash and digest section were defined.

It is currently assumed that the incomplete section indicates an incomplete image created using remote imaging. The incomplete section contains data but currently there is no indication what purpose the data has.

4. EWF-X

EWF-X (extended) is an experimental format to enhance the EWF format. EWF-X is based on the EWF-E01 format. EWF-X does not limit the table entries to 16375. EWF-X is not the same as version 2 of EWF.

TODO add note about the table entry limit.

4.1. Sections

Additional sections provided in the EWF-X format are:

xheader
xhash

4.1.1. Xheader

The xheader section contains a zlib compressed data (see section: 3 Compression) containing XML data containing the header values.

<?xml version="1.0" encoding="UTF-8"?>
<xheader>
        <case_number>1</case_number>
        <description>Description</description>
        <examiner_name>John D.</examiner_name>
        <evidence_number>1.1</evidence_number>
        <notes>Just a floppy in my system</notes>
        <acquiry_operating_system>Linux</acquiry_operating_system>
        <acquiry_date>Sat Jan 20 18:32:08 2007 CET</acquiry_date>
        <acquiry_software>ewfacquire</acquiry_software>
        <acquiry_software_version>20070120</acquiry_software_version>
</xheader>

4.1.2. Xhash

The xhash section contains a zlib compressed data (see section: Compression) containing XML data containing the hash values.

<?xml version="1.0" encoding="UTF-8"?>
<xhash>
        <md5>ae1ce8f5ac079d3ee93f97fe3792bda3</md5>
        <sha1>31a58f090460b92220d724b28eeb2838a1df6184</sha1>
</xhash>

4.2. GUID

EWF-X uses a random based version of the GUID

5. Compression

5.1. Zlib compressed data

The compressed data is stored in the the zlib compressed data format (RFC1950). This format uses big-endian.

The compressed data is variable of size and consists of:

Offset	Size	Description
0.0	4 bits	Compression method
0.4	4 bits	Compression information
1.0	5 bits	Check bits
1.5	1 bit	Preset dictionary flag
1.6	2 bits	Compression level
If the preset dictionary flag is set
2	4	Preset dictionary identifier Adler-32 used to identifier the preset dictionary
Common
…	…	Compressed chunk data
…	4	Checksum Adler-32 of the chunk data

The check bits value must be such that when the first 2 bytes are represented as a 16-bit unsigned integer in big-endian byte order the value is a multiple of 31.

5.1.1. Compression method

Value	Identifier	Description
8		Deflate (RFC1951)

15		Reserved

[RFC1950] only defines 8 as a valid compression method.

5.1.2. Compression information - compression method 8 (Deflate)

For compression method 8 (Deflate) the compression information contains the base-2 logarithm of the LZ77 window size minus 8.

To determine the corresponding window size:

1 << ( 7 + 8 )

E.g. A compression information value of 7 indicates a 32768 bytes window size. Values larger than 7 are not allowed according to [RFC1950] and thus the maximum windows size is 32768 bytes.

5.1.3. Compression level

Value	Identifier	Description
0		Fastest
1		Fast
2		Default
3		Slowest, maximum compression

5.2. Deflate compression

The deflate compressed data consists of one or more deflate compressed blocks. Each block consists of:

block header
block data

5.2.1. Deflate compressed block header

The deflate compressed block header is 3 bits in size and consists of:

Offset	Size	Value	Description
0	1 bit		Last block (in stream) marker: 0 ⇒ not last block 1 ⇒ last block
0.1	2 bits		Block type

5.2.2. Deflate compressed block types

Value	Identifier	Description
0		uncompressed data
1		static Huffman compressed data
2		dynamic Huffman compressed data
3		reserved (not used)

5.2.3. Uncompressed block data

Offset	Size	Description
0.3	5 bits	Empty values (not used)
1	2	Uncompressed data size
3	2	Copy of uncompressed data size Contains a 1s complement of the uncompressed data size
5	…	Uncompressed data

The uncompressed data size can range between 0 and 65535 bytes.

5.2.4. Huffman compressed block data

TODO add description

Compressed data blocks consists of 3 types of symbols:

literal byte values
end-of-block marker
(size, offset) tuples

These symbols are merged in a single "alphabet" where:

Value	Identifier	Description
0x00 - 0xff		literal byte values
0x100		end-of-block marker
0 additional bits
0x101		Size of 3
0x102		Size of 4
0x103		Size of 5
0x104		Size of 6
0x105		Size of 7
0x106		Size of 8
0x107		Size of 9
0x108		Size of 10
1 additional bit
0x109		Size of [11, 12]
0x10a		Size of [13, 14]
0x10b		Size of [15, 16]
0x10c		Size of [17, 18]
2 additional bits
0x10d		Size of [19, 22]
0x10e		Size of [23, 26]
0x10f		Size of [27, 30]
0x110		Size of [31, 34]
3 additional bits
0x111		Size of [35, 42]
0x112		Size of [43, 50]
0x113		Size of [51, 58]
0x114		Size of [59, 66]
4 additional bits
0x115		Size of [67, 82]
0x116		Size of [83, 98]
0x117		Size of [99, 114]
0x118		Size of [115, 130]
5 additional bits
0x119		Size of [131, 162]
0x11a		Size of [163, 194]
0x11b		Size of [195, 226]
0x11c		Size of [227, 257]
0 additional bits
0x11d		Size of 258

The additional bits are stored in big-endian (MSB first) and indicate the index into the corresponding array of size values (or base size + additional size).

Value	Identifier	Description
0 additional bits
0		Offset of 1
1		Offset of 2
2		Offset of 3
3		Offset of 4
1 additional bit

TODO merge with table

             Extra           Extra               Extra
             Code Bits Dist  Code Bits   Dist     Code Bits Distance
             ---- ---- ----  ---- ----  ------    ---- ---- --------
               4   1   5,6    14   6    129-192   24   11   4097-6144
               5   1   7,8    15   6    193-256   25   11   6145-8192
               6   2   9-12   16   7    257-384   26   12  8193-12288
               7   2  13-16   17   7    385-512   27   12 12289-16384
               8   3  17-24   18   8    513-768   28   13 16385-24576
               9   3  25-32   19   8   769-1024   29   13 24577-32768
10   4     33-48    20    9   1025-1536
11   4     49-64    21    9   1537-2048
12   5     65-96    22   10   2049-3072
13   5     97-128   23   10   3073-4096

5.2.5. Dynamic Huffman compressed block data

Offset	Size	Value	Description
0.3			Code size
			Distance code

TODO merge with table

               5 Bits: HLIT, # of Literal/Length codes - 257 (257 - 286)
               5 Bits: HDIST, # of Distance codes - 1        (1 - 32)
               4 Bits: HCLEN, # of Code Length codes - 4     (4 - 19)
 (HCLEN + 4) x 3 bits: code lengths for the code length
                  alphabet given just above, in the order: 16, 17, 18,
                  0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15

                  These code lengths are interpreted as 3-bit integers
                  (0-7); as above, a code length of 0 means the
                  corresponding symbol (literal/length or distance code
                  length) is not used.

               HLIT + 257 code lengths for the literal/length alphabet,
                  encoded using the code length Huffman code

               HDIST + 1 code lengths for the distance alphabet,
                  encoded using the code length Huffman code

               The actual compressed data of the block,
                  encoded using the literal/length and distance Huffman
                  codes

               The literal/length symbol 256 (end of data),
                  encoded using the literal/length Huffman code

         The code length repeat codes can cross from HLIT + 257 to the
         HDIST + 1 code lengths.  In other words, all code lengths form
         a single sequence of HLIT + HDIST + 258 values.

The code size is encoded in the following Huffman encoding:

Value	Identifier	Description
0 - 15		Represent code size of 0 - 15
16		Copy the previous code size 3 - 6 times. The next 2 bits indicate repeat length (0 = 3, … , 3 = 6) Example: Codes 8, 16 (+2 bits 11), 16 (+2 bits 10) will expand to 12 code lengths of 8 (1 + 6 + 5)
17		Repeat a code length of 0 for 3 - 10 times. (3 bits of length)
18		Repeat a code length of 0 for 11 - 138 times (7 bits of length)

A code size of 0 indicates that the corresponding symbol in the literal/length or distance alphabet will not occur in the block, and should not participate in the Huffman code.

5.2.6. Decompression

TODO add description

do
{
    read block_header from input stream

    if( block_header.type == UNCOMPRESSED )
    {
        align with next byte
        read block_header.size and block_header.size_copy
        read data of block_header.size
    }
    else
    {
        if( block_header.type == HUFFMANN_DYNAMIC )
        {
            read representation of code trees (see subsection below)
        }
        loop (until end of block code recognized)
        {
            decode literal/length value from input stream
            if( value < 256 )
            {
                copy value (literal byte) to output stream
            }
            else
            {
                if value = end of block (256)
                {
                    break from loop
                }
                else (value = 257..285)
                {
                    decode distance from input stream

                    move backwards distance bytes in the output
                    stream, and copy length bytes from this
                    position to the output stream.
                }
            }
        }
    }
}
while( block_header.last_block_flag == 0 );

5.3. Adler-32 checksum

The checksum algorithm provided by [ASR02], slightly altered for readability. The algorithm used is Alder-32 and [ASR02] incorrectly refers to it as a CRC.

uint32_t Expert_Witness_Compression_CRC(
          uint8_t *buffer,
          size_t buffer_size,
          uint32_t previous_key )
{
	size_t buffer_iterator = 0;
	uint32_t lower_word    = previous_key & 0xffff;
	uint32_t upper_word    = ( previous_key >> 16 ) & 0xffff;

	for( buffer_iterator = 0;
	     buffer_iterator < buffer_size;
	     buffer_iterator++ )
	{
		lower_word += buffer[ buffer_iterator ];
		upper_word += lower_word;

		if( ( buffer_iterator != 0 )
		 && ( ( buffer_iterator % 0x15b0 == 0 )
		  || ( buffer_iterator == buffer_size - 1 ) ) )
		{
			lower_word = lower_word % 0xfff1;
			upper_word = upper_word % 0xfff1;
		}
	}
	return( ( upper_word << 16 ) | lower_word );
}

Zlib provides the function adler32 which is an optimized version of the algorithm.

6. Corruption scenarios

This chapter contains several corruption scenarios that have been encountered "in the wild".

6.1. Corrupt uncompressed chunk

TODO add description

6.2. Corrupt compressed chunk

TODO add description

6.3. DEFLATE uncompressed block data with copy of uncompressed data size of 0

Seen in combination with some firmware versions of Tableau TD3 forensic imager.

In this corruption scenarion the copy of uncompressed data size value of the DEFLATE uncompressed block data is set to 0 instead of the 1s complement of the uncompressed data size.

Libewf currently does not handle this corruption scenario.

6.4. Corrupt section descriptor

TODO add description

libewf_section_start_read: reading section start from file IO pool entry: 1 at offset: 415912423
libewf_section_start_read: type                      : table2
libewf_section_start_read: next offset               : 415978027
libewf_section_start_read: size                      : 65604
libewf_section_start_read: checksum                  : 0xf35f03e0
libewf_section_table_header_read: number of offsets  : 16375
libewf_section_table_header_read: base offset        : 0x00000000
libewf_section_table_header_read: checksum           : 0x180d0137

libewf_section_start_read: reading section start from file IO pool entry: 1 at offset: 415978027
libewf_section_start_read: type                      : sectors
libewf_section_start_read: next offset               : 415978027
libewf_section_start_read: size                      : 0
libewf_section_start_read: checksum                  : 0x1ad00464

6.5. Corrupt table section

TODO add description

with and with out table 2

number of entries

entry data

6.6. Corrupted segment file header

TODO add description

6.7. Partial segment file

TODO add description

6.8. Missing segment file(s)

TODO add description

6.9. Dual image: section size versus offset

The sections descriptors define both the next section offset and the size of the section. If an implementation reads only one of the two to determine the next section, a dual EWF image can be crafted that consists of two separate images including hashes.

A current version of libewf will mark such an image as corrupted, but older versions only checked the section size and will show one of the two valid images.

6.10. Table entries offset overflow

In EnCase 6.7.1 the sectors section can be larger than 2048 MiB. The table entries offsets are 31 bit values in EnCase6 the offset in a table entry value will actually use the full 32 bit if the 2048 MiB has been exceeded. This behavior is no longer present in EnCase 6.8 so it is assumed to be a bug.

Libewf currently assumes that the if the 31 bit value overflows the following chunks are uncompressed. This allows EnCase 6.7.1 faulty EWF files to be converted by libewf.

6.11. Multiple incomplete segment file set identifiers

Although rare it can occur that a set of EWF image files changes its segment file set identifier. This was seen in an image created by EnCase 6.13, presumably using remote imaging. The image contained 3 different segment file set identifiers. The first changes after an incomplete section. The second one changed without any clear indication. The corresponding data section also changed in some extent e.g. compression method and media flags, the is physical flag being dropped. The change was consistent across multiple segment files. It is unlikely that deliberate manipulation is involved. EnCase considers the image as invalid.

Although with some tweaking of libewf the individual segment file sets could be read. In this case the data read from the segment file sets was heavily corrupted. For now a stock libewf does not support reading multiple segment files sets from a single image, but this might change in the future.

7. AD encryption

As of version 2.8 FTK Imager supports "AD encryption". Although the output file uses the EWF extensions the file actually is a AES-256 encrypted container. The EWF can be encrypted using a pass-phrase or a certificate.

The AccessData encryption format is a single-file encryption method often used to encrypt AccessData and EnCase forensic images. The input file (which can be anything) is encrypted with AES using a user-supplied password or public key and a header is prepended onto the resulting ciphertext to allow for decryption with the same password or corresponding private key.

The container consists of a header followed by the encrypted data. The header is padded out to the nearest 512-byte boundary (typically it is just 512 bytes); all header values are in little-endian order.

Only the first segment has the AD crypt header. All subsequent segment files only contain data encrypted with the same key and a different counter (CTR) per file.

7.1. AD crypt header

The AD crypt header is 512 bytes in size and consists of:

Offset	Size	Value	Description
0	8	"ADCRYPT\x00"	File signature
8	4	0x01000000	Version
12	4		Header size (or offset of encrypted data)
16	2		Number of passwords Contains -1 if not set
18	2		Number of raw keys Contains -1 if not set
20	2		Number of certificates Contains -1 if not set
22	2		Reserved (must be 0x0000)
24	4		Encryption algorithm: 1=AES-128, 2=AES-192, 3=AES-256
28	4		Hash algorithm: 1=SHA-256, 2=SHA-512
32	4		PBKDF2 iteration count (I)
36	4		Salt length (S)
40	4		Key length (K)
44	4		HMAC length (H)
48	S		Encrypted salt (ESALT)
48 + S	K		Encrypted key (EKEY)
48 + S + K	H		HMAC of encrypted key (HMAC)

The header is then padded with null bytes to the following 512-byte boundary, after which follows the encrypted file.

Although the encryption protocol has some configurable settings, most (if not all) files will use the defaults: AES-256 for encryption, SHA-512 for hashing, 4000 iterations of PBKDF2.

7.2. Encryption

All AES encryption steps use AES in CTR mode with an IV of all 0-byte values and a simple incrementing little-endian counter starting at 0. Where 0 is the first segment file, 1 is the second segment file, etc. The IV is determined as follows:

IV = SEGMENT INDEX << 64

The encryption protocol is as follows:

Generate a random encryption key FKEY of length K
Encrypt the target file with the specified AES version and key FKEY
Generate a random salt SALT
Generate a new encryption key PKEY from the user password hashed with the specified hash algorithm (or the empty string, if there is no user password): PKEY = PBKDF2(hash(user_pw) || '', SALT, I, K)
Encrypt FKEY using the specified AES version and key PKEY to generate EKEY
If the user supplied a public key, use it to encrypt SALT and generate ESALT, otherwise ESALT = SALT
Compute an HMAC of the encrypted key EKEY with PKEY using the specified hash algorithm

The decryption procedure is thus:

If using a private key, decrypt the encrypted salt ESALT to get the original SALT (if no key, SALT = ESALT)
Regenerate the encryption key PKEY from the user password hashed with the specified hash algorithm (or the empty string, if there is no user password): PKEY = PBKDF2(hash(user_pw) || '', SALT, I, K)
Optionally verify the HMAC of EKEY using PKEY and the specified hash algorithm, comparing it with the header HMAC
Decrypt the encrypted key using AES with PKEY to get FKEY
Decrypt the file ciphertext using AES with FKEY

7.3. Notes

TODO add description metadata (volume, data, headers)

8. Notes

What about:

PALM volume
the SMART logs

8.1. Header

All test headers consist of the where spaces are actually tabs separated values

srce
0       1
p       n       id      ev      tb      lo      po      ah      gu      aq
0       0
                                        -1      -1

sub
0       1
p       n       id      nu      co      gu
0       0
                                1

8.2. Ltree

When p = 0 n contains a numeric value (the number of child entries of the following entry) When p = 1 n contains the name of the directory. When p = is empty n contains the name of the file.

Appendix A: References

[ASR02]

Title:	AD Image Encryption
Version:	1.2
Date:	May 17, 2010
Author(s)	Access Data
URL:	https://support.accessdata.com/hc/en-us/article_attachments/201953867/AD1___Image_Encryption_Technical_White_Paper.pdf

[ASR02]

Title:	ASR Expert Witness Compression Format specification
Author(s)	Andrew Rosen
URL:	http://www.asrdata.com/SMART/whitepaper.html

[COH]

Title:	PyFlag libevf source code
Author(s)	Michael Cohen
URL:	http://www.pyflag.net/

[FWIKI]

Title:	Forensic Wiki
URL:	http://www.forensicswiki.org/index.php/Forensic_file_formats http://www.forensicswiki.org/index.php/EnCase

[RFC1950]

Title:	ZLIB Compressed Data Format Specification
Version:	3.3
Author(s):	P. Deutsch, J-L. Gailly
Date:	May 1996
URL:	http://www.ietf.org/rfc/rfc1950.txt

[RFC1951]

Title:	DEFLATE Compressed Data Format Specification
Version:	1.3
Author(s):	P. Deutsch
Date:	May 1996
URL:	http://www.ietf.org/rfc/rfc1951.txt

[RFC4122]

Title:	A Universally Unique Identifier (UUID) URN Namespace
Author(s):	P. Leach, M. Mealling, R. Salz
Date:	July 2005
URL:	http://www.ietf.org/rfc/rfc4122.txt

Appendix B: GNU Free Documentation License

Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

0. PREAMBLE

The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

1. APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.

A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document’s overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.

The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not "Transparent" is called "Opaque".

Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

The "publisher" means any person or entity that distributes copies of the Document to the public.

A section "Entitled XYZ" means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as "Acknowledgements", "Dedications", "Endorsements", or "History".) To "Preserve the Title" of such a section when you modify the Document means that it remains a section "Entitled XYZ" according to this definition.

The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

2. VERBATIM COPYING

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Files

Expert Witness Compression Format (EWF).asciidoc

Latest commit

History

Expert Witness Compression Format (EWF).asciidoc

File metadata and controls

EWF specification

Summary

Document information

License

Revision history

1. Overview

1.1. Test version

2. Segment file

2.1. File header

2.1.1. EWF, EWF-E01 and EWF-S01

2.1.2. EWF-L01

2.2. Segment file extensions

2.2.1. EWF-S01

2.2.2. EWF-E01

2.2.3. EWF-L01

2.3. Segment file set identifier GUID

3. The sections

3.1. Section descriptor

3.2. Section types

3.3. Header2 section

3.3.1. EnCase 4 (EWF-E01)

3.3.2. EnCase 5 to 7 (EWF-E01)

Main category

Notes

Sources category

Subjects category

3.3.3. EnCase 5 to 7 (EWF-L01)

3.3.4. Header2 values

3.4. Header section

3.4.1. EWF format

3.4.2. EnCase 1 (EWF-E01)

3.4.3. SMART (EWF-S01)

3.4.4. EnCase 2 and 3 (EWF-E01)

3.4.5. EnCase 4 to 7 (EWF-E01)

3.4.6. linen 5 to 7 (EWF-E01)

Main category

Sources category

Subjects category

3.4.7. FTK Imager (EWF-E01)

3.4.8. EnCase 5 to 7 (EWF-L01)

3.4.9. Header values

Notes

3.5. Volume section

3.5.1. EWF specification

3.5.2. SMART (EWF-S01)

3.5.3. FTK Imager, EnCase 1 to 7 and linen 5 to 7 (EWF-E01)

3.5.4. EnCase 5 to 7 (EWF-L01)

3.5.5. Media type

3.5.6. Media flags

3.5.7. Compression level

3.6. Disk section

3.7. Data section

3.7.1. FTK Imager, EnCase 1 to 7 and linen 5 to 7 (EWF-E01)

3.7.2. EnCase 5 to 7 (EWF-L01)

3.8. Sectors section

3.8.1. Data chunk

3.8.2. Optical disc images

3.9. Table section

3.9.1. EWF specification

Table header

Table entry

Data chunk

3.9.2. SMART (EWF-S01)

3.9.3. EnCase 1 (EWF-E01)

Table header

Table entry

Table footer

Data chunk

3.9.4. FTK Imager and EnCase 2 to 5 and linen 5 (EWF-E01)

Table header

Table entry

Table footer

3.9.5. EnCase 6 to 7 and linen 6 to 7 (EWF-E01)

Table header