MAT stands for Metadata Anonymisation Toolkit.
It's a toolbox composed of a GUI application, a CLI application, and a library.
Metadata
What is a metadata ?
Metadata consist of information that characterizes data (eg. Word documents, pictures, music files, etc). In essence, metadata answer who, what, when, where, why, and how about every facet of the data that is being characterized.
Why metadata can be a risk for your privacy ?
Metadata within a file can tell a lot about you. Cameras record data about when a picture was taken and what camera was used. Office documents like pdf or Office automatically add author and company information to documents and spreadsheets. Maybe you don't want to disclose those information on the web.
Why MAT is not the ultimate solution ?
Mat only removes metadata from your files, it does not anonymise their content, nor handle watermarking, steganography, or any overly customized metadata field/system.
If you really want to be anonymous, use format that does not contain any metadata, or better : use plain-text.
And most important, be careful : every format can be watermarked, even plain text ! (eg. the SNOW project)
How does MAT works ?
Proudly powered by Python, and using Hachoir as much as possible. MAT was orignally written during the GSoC 2011, under the umbrella of the Tor project.
Supported formats so far:
Portable Network Graphics (.png)
JPEG (.jpg, .jpeg, ...)
Open Documents (.odt, .odx, .ods, ...)
Office OpenXml (.docx, .pptx, .xlsx, ...)
Portable Document Fileformat (.pdf)
Tape ARchives (.tar, .tar.bz2, .tar.gz, ...)
Zip (.zip)
MPEG AUdio (.mp3, .mp2, .mp1, ...)
Ogg Vorbis (.ogg, ...)
Free Lossless Audio Codec (.flac)
Torrent (.torrent)
https://mat.boum.org/
https://git.torproject.org/user/jvoisin/mat.git
Comments and Reviews
It removes more metadata than Exiftool. It even removed docx metadata that exiftool currently does not remove.
It works on many platforms, and you can try it free online here: https://metadata.systemli.org/