Most of PDF files available on internet have use restriction (impression, modification, copy). When you see them with the famous lock, that means that the document is under restriction.
Advanced PDF Password Recovery is a very important tool to remove restriction of password-protected PDF files. Because of the restriction you cannot print them, modify them, select and/or copy the text to the clipboard. But with this program, all the restrictions will be removed.
Advanced PDF Password Recovery functions with all the versions of Acrobat Adobe. But it can also convert Kinko Document (KDF) files into PDF by removing all restrictions.