I'm providing a free sample page that will be downloaded from my website that is in .pdf format. I want to prevent users from selecting and copying the text content of that document. How can I do this for free?
With Adobe Acrobat, you can create passwords to protect pdf files. But others can still use some pdf tools to crack passwords. Look at this article. http://www.anypdftools.com/blog/2009/05/12/create-and-crack-pdf-password.html#261