Leaked police training materials suggested that Apple can provide authorities with backdoor access to your iPhone. At Ars Technica, Jacqui Cheng investigated whether it was true or not, and found that it's technically possible, but unlikely:
Apple holds the key to encrypted iCloud data on its own servers—if law enforcement sent the appropriate subpoena, the company can easily decrypt your cloud-stored data and send it off to the authorities. Could this apply to the iPhone too? It seems the answer is no: both Mogull and Miller pointed out that an iPhone user's data under Data Protection is encrypted using a key that is derived from the user-set PIN/passcode, and if no one knows what the user has chosen, it will be very difficult to crack the key. This makes it different than iCloud, where Apple ultimately holds the encryption key for any data stored there.
