One of the big issues of the Internet revolution is protecting digital content. How do you stop people freely distributing your material without paying for it? The PDF file format has lots of encryption and security features within the file but how do you stop people from editing or copying from a PDF file and users can just swap the passwords or reprint the PDF as a new PDF. So how do you secure the file itself?
There are essentially 2 ways to deal with this issue if you are using a PDF file.
Firstly you can put it inside some kind of wrapper which adds extra security features. This is what services and products like Zinio do. The Zinio file is a PDF inside a Zinio file – the Zinio reader adds extra security features which aim to make it harder to copy and use on unauthorized machines.
The second way is to stop the user getting access to the file altogether. If the file is viewable but not saveable you can give the user access without to the file so it is not possible to copy. Provide a viewer which allows the user to open the PDF files from a remote location (ie your website) and view but not save the PDF. The PDF itself can be encrypted or kept in memory, making it impossible to copy. It also makes it very easy to provide a limited demo version with limited functionality like no printing. This is one popular use of our JPedal software as an applet or a custom application.
There are two important issues to remember with copy protection. The first is that no protection system is unbreakable – you are just trying to make sure it is not worth the bother to crack your content.
Secondly, a protection system that makes life hard for your customers can reduce sales. So it needs to hinder copying without deterring genuine users. It is a delicate balance to achieve. Good luck and let us know if you have any suggestions or tips?
IDRsolutions develop a Java PDF library, a PDF forms to HTML5 converter, a PDF to HTML5 or SVG converter and a Java Image Library that doubles as an ImageIO replacement. On the blog our team post about anything interesting they learn about.