Your example of 10^8 combination, a 8 digit passcode on an iPhone 4, means a policeman would have to sit on a desk and try combinations for hundreds of years. T

Your example of 10^8 combination, a 8 digit passcode on an iPhone 4, means a policeman would have to sit on a desk and try combinations for hundreds of years. This is likely to be determined as unbreakable protection by a court. The document in page 11-12 goes into what may constitute cryptographic conventions. It considers all recent iPhone and Android phones to be. It considers all systems for unlocking a mobile phone to be, as there is no other ways to access data on the phone otherwise, given normal technical knowledge and no specific software or hardware.