Remove metadata from files
Metadata is data about data. Metadata answers who, what, when, where, why, and how about every facet of the data that is being documented.
Photos, and images in general, contain metadata. For photos this includes how large the picture is, colour depth, resolution, the date and time when it was created, the GPS coordinates of the location they were taken at, camera shutter setting details, and possibly even the name of the program used to edit them.
Document metadata is information about one or more aspects of a document, spreadsheet, pdf file, that is not always visible to the person creating them, but can be found by the person who receives them next. Comments, track changes, hidden text, mark-ups, properties, attachments and bookmarks are all examples of document metadata. Office documents like pdf or Office automatically add author and organisation information to documents and spreadsheets.
Web pages often include metadata in the form of meta tags. Description and keywords meta tags are commonly used to describe the Web page’s content. Most search engines use this data when adding pages to their search index.
This type of metadata can be useful, but maybe you do not want to disclose this information on the web, because metadata can be used for other purposes as well:
Metadata is collected by corporations for psychological manipulation in persuasion and advertising.
Metadata also plays a number of important roles in computer forensics:
It can provide corroborating information about the document data itself.
It can reveal information that someone tried to hide, delete, or obscure.
It can be used to automatically correlate documents from different sources.
Metadata is used by hackers doing reconnaissance for an attack
And last but not least, it can be used to correlate data in dragnet and targeted surveillance.
Techniques for metadata removal
Metadata removal software like BleachBit