Question

I have created hundreds of folders and text files using php, I then add them to a zip archive.

This all works fine but if I create another zip archive using the same folders and files, the new archive will have a different hash to the first one. This is the same if I use winrar instead of php to create an archive.

It only seems to show different hashes when I zip the files I have created through php, yet they open fine.

Very strange anyone shed any light on this?

Thanks

Answer 1

There is certainly some difference in the files. If the lengths are not exactly the same, the hash will be different. You can use a comparing hex editor, like Hex Workshop for example, to see what exactly the differences are.

Possibilities that come to my mind:

1. As @orn mentioned, there may be a timestamp in the zip format you are using (not sure).
2. The order that the files are added to the archive may be different (depending on how you’re selecting them / building the source array).