The new iPhone has encryption that protects the contents of the phone. This means if someone steals your phone - if a hacker or something images your phone - they can't read what's on the phone itself, they can't look at your pictures, they can't see the text messages you send, and so forth. But it does not stop law enforcement from tracking your movements via geolocation on the phone if they think you are involved in a kidnapping case, for example.