What private information does zip file contain, in addition to the zipped documents?

Questions
1

for example, does it contain the name of your pc, location… this kind of information that leaks your privacy?

1 Like
2

This sounds like an issue of the encrypting software/app/program itself rather than the zip file format. AFAIK, it should not include any other piece of metadata from the source itself.

I think the actual metadata of the files inside rather than along the zip file itself are the one that cpuld betray you (like the picture metadata including your location and device IDs).

2 Likes
3

ZIP files can contain three types of metadata:

  • File entries timestamps
  • File entries comments
  • Global ZIP comment

File entries “Last Modified” timestamp will always be included. “Created” and “Last Accessed” could also be included. (7zip, for example, writes these too)

File entries comments can be attached to each file in the ZIP, separately. 7zip supports these. (right-click on the file and select “Comment” from the menu)

Global ZIP comment, that pertains to the whole ZIP file can be included in theory, but I don’t know any tool that can add or show it.

In practice, both types of comments are very rarely used. In theory, if some application that you’ve used produced a ZIP file, it could place arbitrary info in the comments sections, but it’s extremely unlikely, certainly not private info. Common ZIP tools like 7zip don’t add any comment automatically.

If you want to reset the timestamps and make sure no comments are included in the ZIP file, you can use BatchPurifier to scrub metadata. (it supports ZIP files, among others)

1 Like