TOPIC: Remove protection

A client just told me that he opened the file with PDF Pro
and was able to remove the password.
How can I protect the file that no one will be able to open the protection?

Hello,

For highest security I recommend having the master password setup in ebook store as tightens the security as some readers choose to ignore the password if the master password is not set. The field is under PDF Protection tab. There always will be tools to try and crack the passwords though, but so far this have been the most secure method to redistribute pdf files.

Thanks