Actually, not sure as to whether there is even a password (or it could be one of these incredibly long random strings of text). I think that it could be a key or certificate that is used to seal the ZIP files. Even though it may prompt you for a password then there is no way of putting it in since it is a key that is used. Then again, I don't think that it is "12345"...
https://www.youtube.com/watch?v=a6iW-8xPw3k
Gratuitous Spaceballs reference...