The Apple iOS 8 will include encryption that prevents even Apple from accessing what is on a person's e-Phone - even with a valid police warrant:
http://www.washingtonpost.com/busine...92f_story.html
Of course, it doesn't protect data that is NOT in the iPhone. Data that is stored in a cloud service or elsewhere on the Internet can still be accessed.
But, so long as you don't sync the phone with a remote server, you have enhanced protection.