A simple utility that removes any protection to pdf that can be opened without password.
git clone https://github.com/totomz/pdf-decrypter; cd pdf-decrypter- Put your pdf in
input/folder - Execute
java -jar pdf-decrypter.jar
This code works only with iText 2.0.2 (newer versions have more constraints related to password and encryption of pdf files...this code works only with 2.0.2).
Specific version of iText and dependencies are in lib/ folders; you may or not install them in your local repository (are included at compile time as system dependendcies)
This code was done around 2012 for managing some invoice from which the cut&paste was prevented (without any reason - why I am not allowed to copy the contents of an invoice issued to ME?). It is almost the same code as it was (90 lines of code - there is nothing to refactor at all :)