PRIVACY: Apple’s iOS 11.4 update with ‘USB Restricted Mode’ may defeat tools like GrayKey.

“To improve security, for a locked iOS device to communicate with USB accessories you must connect an accessory via Lightning connector to the device while unlocked — or enter your device passcode while connected — at least once a week,” reads Apple documentation highlighted by security firm ElcomSoft. The feature actually made an appearance in iOS 11.3 betas, but like AirPlay 2 was removed from the finished code.

The change blocks use of the Lightning port for anything but charging if a device is left untouched for seven days. An iPhone or iPad will even refuse to sync with computer running iTunes until iOS is unlocked with a passcode.

USB Restricted Mode may be intended to impose a seven-day window on when digital forensics specialists like Grayshift can break into a device, at least using any simple techniques. Those firms will often employ a “lockdown” record from a suspect’s computer to create a local backup of iPhone data, skipping passcode entry.

Smart.