Metadata: Data about Data
The former director of the NSA and the CIA, General Michael Hayden, claimed “We kill people based on metadata.”
Metadata is often overlooked when it comes to protecting privacy, as this data is normally invisible to the user.
However, metadata in particular is easy to obtain and is well suited for the creation of profiles and relationships.
Invisible in a photo file is information about when, where and how the photo was taken and some of these data such as device and settings often allows conclusions about who took the photo.
And even though automated processing of the photos themselves is making great strides, the metadata in particular provide a lot of sensitive information that is easy to process.
Often, the file's metadata can be combined with other metadata such as the IP address or telephone number, for example when the files are uploaded in a cloud or shared in a chat.
This also applies to other files.
You can use for example tools like Exif Info to take a look at the metadata of files.
Encrypted zip Files
Normally, the metadata of files in zip archives can be easily viewed. However, when the zip archive is then encrypted, this metadata is also encrypted. Geo-data, file names etc. can be protected in this way.
But keep in mind: Like all files, zip files also contain metadata.