Apple has managed to prevent the hottest iPhone hacking company in the world from doing its thing. In March, Atlanta-based Grayshift promised governments its GrayKey tech could crack the passcodes of the latest iOS models, right up to the iPhone X. From then on, Apple continued to invest in security in earnest, continually putting up barriers for Grayshift to jump over. Grayshift continued to grow, however, securing contracts with Immigration and Customs Enforcement, and the Secret Service. Now, though, Apple has put up what may be an insurmountable wall. Multiple sources familiar with the GrayKey tech tell Forbes the device can no longer break the passcodes of any iPhone running iOS 12 or above. On those devices, GrayKey can only do what's called a "partial extraction," sources from the forensic community said. That means police using the tool can only draw out unencrypted files and some metadata, such as file sizes and folder structures. Previously, GrayKey used "brute forcing" techniques to guess passcodes and had found a way to get around Apple's protections preventing such repeat guesses. But no more. Though it's clear Apple has locked GrayShift out, no one actually knows just how the iPhone maker has done it. Vladimir Katalov, chief of forensic tech provider Elcomsoft, has repeatedly uncovered weaknesses in Apple technology. But he was stumped too.