File Encryption/Decryption in Xcode

My iPad application displays a开发者_如何学JAVA set of PDFs, png images and mov video files. All these files are stored in my Xcode project bundle, and I am accessing it from there. When I am installing the app in my device, is it possible to hack and access those files?

If so, I would like to encrypt them before adding it to my Xcode project bundle, and decrypt them from within the source code when I am reading and displaying those files. How can I do it?

Thanks in advance.