There is not much information about the latest features of iOS 8. No third party is allowed to take the photos or use Video apps using the camera or the hardware until and unless there is a specific approval for it from the user’s end. If the apps are from the same developer then there is more sharing of information of private nature. There are App Groups operating between various apps to facilitate exchange of information. Its advantage is in the fact that you need not type the username or password every time you desire to post some content on social networking sites.
HealthKit and HomeKit are 2 additional security options with you to choose from. For example- you do not wish to share the information like your weight, then, you just need to deactivate that option in Settings.app. Blackberry customers may become the target of Apple's security measures due to the reason that iphone is not considered secure. For further technical information and have a better understanding on this topic, check out Luis Abreu’s website and the article on ‘iOS 8 Privacy Updates’.