Can I “Stamp” a .zip file with Data when a file is being downloaded?

Question

is there a way that I can "Stamp" my .zip files with some type of hidden Data (like the email address of the buyer/downloader) every time that .zip is being downloaded?

Basically trying to inject some type of Unique variable into the .zip, for tracking/security reasons.

I'm not even sure if I can modify a .zip like that, but I figured that I should ask, because I've been searching around and could not find an answer.

Answer 1

How would you go about "tracking" this zip file?

Are you going to ask the user to send you the zip file so you can see if it's legitimate? Not sure what you're going for here.

Having said that. Some ideas:

Take the contents of the zip file concatenated with the email address of the buyer/downloader + some key that only you know. Take the MD5 of that and name the zip file {THATMD5}.zip. Or, you could put something like Key.txt into the zip file and key.txt could contain {THATMD5}. Again, not sure how you plan to "track" this though.