This is article describes how to "unlock" a secured PDF file, and gain full access to print it, modify it, and copy selected portions of text from it, without paying anything to buy any of this (so called) "pdf cracking software".
You are going to need the help of the Evince Document Viewer that comes with Ubuntu Linux. If you are already using Ubuntu Linux, good for you! If you are not using it, you can ask a friend of yours with Ubuntu installed to help you. Otherwise, you can dive in deep water and try the Live CD that will do the job for you (no installation required).
A "secured" PDF file will look like this if you open it in Adobe Reader:
Boot in your Ubuntu Linux (or boot from the Live CD if you don't want Ubuntu Linux installed). Open your locked PDF from Ubuntu using the standard document viewer, Evince. From the menu go to File → Print... From the printers list select Print to File:
Enter the output filename and make sure that you have selected PDF as Output Format. Click Print and you will get a verbatim copy of the original file, only this time it will be free of any restrictions. This is one more practical example that demonstrates how Ubuntu Linux can significantly improve your life...