MCrypt
From Just Solve the File Format Problem
MCrypt is a command-line encryption utility. It is widely available on Unix-based systems.
Identification
Files that use the MCrypt file format begin with 00 6d 03
(MCrypt 2.5), or 00 6d 02
(MCrypt 2.2).
Not all files supported by MCrypt use this format. It also supports "bare" encrypted files, which can't be identified by their contents.
Software
- MCrypt → mcrypt, mdecrypt