To say that Apple and law enforcement around the world have a contentious relationship is an understatement. Each time law enforcement gets a tool that allows accessing iPhones with a court order when the owner can't be compelled to unlock the device, Apple works hard to break that tool. Such is the case with the GrayKey iPhone cracking tool that police around the world have been using to gain access to iPhone devices. Until iOS 12 launched, the GrayKey tool allowed the unlocking of iPhone devices by law enforcement.
On any device running iOS 12 or higher, the tool reportedly no longer works. Multiple sources that are familiar with the GrayKey tech have told Forbes that the tool can no longer break the passcode of any iPhone on iOS 12 or higher. When the tool is used on iPhones running iOS 12 or higher, it is only able to perform a "partial extraction" according to Forbes sources in the forensic community. A partial extraction is only able to pull unencrypted files and some metadata like file sizes and folder structures from the device.
The GrayKey tool was able to unlock iPhones previously by using a brute force technique to guess passcodes. The inability of GrayKey to crack passwords of iOS 12 or higher devices was confirmed by Captain John Sherwin of the Rochester Police Department in Minnesota. Sherwin also stated that he believes in time GrayKey will find a workaround allowing the cat and mouse game to continue.
The challenge for law enforcement with passcode-protected iPhones is that suspects can’t be compelled to unlock the device due to constitutional rights; fingerprint or Face ID unlocking can be compelled.