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Encase is an all-in-one computer forensics suite from Guidance Software Inc.


File Format

Perhaps the de facto standard for forensic analyses in law enforcement, Guidance Software's EnCase Forensic encase} uses a proprietary format for images, reportedly based on ASR Data's Expert Witness Compression Format. EnCase's Evidence File .E01) format contains a physical bitstream of an acquired disk, prefixed with a '"Case Info" header, interlaced with CRCs for every block of 64 sectors~(32 KB), and followed by a footer containing an MD5 hash for the entire bitstream. Contained in the header are the date and time of acquisition, an examiner's name, notes on the acquisition, and an optional password; the header concludes with its own CRC.

Encase can store media dat into multiple evidence files, which are called segment files. Each segment file consist of multiple sections. Each section consist of a section start definition. This contains a section type.

At least from Encase 3 the case info header is contained in the "header" section, which is defined twice within the file and contain the same information.

With Encase 4 an additional "header2" section was added. The "header" section now appears only once, but the new "header2" section twice.

Version 3 of The Encase F introduced an "error2" sections that it uses to record the location and number of bad sector chunks. The way it handles the sections it can't read is that those areas are filled with zero. Then Encase displays to the user the areas that could not be read when the image was acquired. The granularity of unreadable chunks appears to be 32K.

Within Encase 5 the amount of sectors per block (chunk) can vary.

Encase from at least in version 3, 4 and 5 can hash the data of the media it acquires. It does this by calculating a MD5 hash of the original media data and adds a hash section to the last of the segment files.


File Systems Understood

File Search Facilities

Historical Reconstruction

Can it build timelines and search by creation date?

Searching Abilities

Can it search? Does it build an index? Can it focus on file types or particular kinds of metadata?

Hash Databases

Encase uses MD5 hashes and uses a proprietary file format to store them. It can also import hashes from the NSRL, Hashkeeper, and plain MD5 files.

Evidence Collection Features

Can it sign files? Does it keep an audit log?


Originally written in (YEAR), it has now developed into a Forensic Edition and an Enterprise Edition.

License Notes

Is it commercial or open source? Are there other licensing options?

External Links

EnCase Homepage - http://www.guidancesoftware.com/lawenforcement/ef_index.asp

External Reviews