I have been doing some works with pdf files auto fill with itextsharp. one of the file that client gave me was secure and password protected. When ever I try to open this using Adobe Acrobat Pro. Its shows that it have to be opened by Adobe life cycle designer.
Then I installed Adobe life cycle designer and tried opening it, unfortunately end up getting a password window and couldn’t proceed.
Then of course googled it and found this awesome web where you can unlock pdf online.