A pocket device that in a few seconds is able to try all the possible combination and find the correct one to open the door. At Black Hat 2017 hacker conference, the expert Colin OFlynn presented an interesting report on breaking electronic door locks. The attacker needs the physical access to the locks internal component to add their own code. The attack works because there is no authentication in place to check with component communicates with the connector. O’Flynn created a device that can check 120 codes per minute, trying all possible four-digit PIN combinations.”]
Source: https://securityaffairs.co/wordpress/61817/hacking/electronic-locks-hacking.html