EnCase is a family of all-in-one computer forensics suites sold by Guidance Software. These products include EnCase Enterprise, EnCase Forensic Edition, EnCase eDiscovery, and EnCase Lab Edition. These programs use a proprietary image file format that has been reverse engineered. Users can create scripts, called EnScripts, to automate tasks.
Expert Witness (for Windows) was the original name for EnCase (dating back to 1998). More info about this can be found on the Internet Archive 1 including a demo of the original software 2.
EnCase uses MD5 hashes and stores them in its proprietary Encase hash file format; either individually or in a "hash map". EnCase supports importing hashes from the NSRL, Hashkeeper, and plain MD5 files.