iOS 11 has a new safety feature that could help when your back’s against the wall. The iPhone’s Touch ID fingerprint sensor is great for quickly unlocking your device, but it’s also been used by law enforcement to circumvent legal restrictions on demanding a passcode. Reverting to passcode access only currently requires a restart via long pressing the sleep button and swiping power off the screen, which is neither discreet nor fast enough if you’re being accosted in the street by someone in a position of authority who wants access to your device.