US Patent 9280653 Security access method for automotive electronic control units

A system and method for employing a mechanism for unlocking a vehicle ECU. The ECU stores a unique ECU identification value that identifies the particular ECU and a secure server stores the ECU identification value and a unique ECU security key value, where the identification value identifies the security key value in the server, and where the secure server stores the unique ECU identification value and the unique security key value for many ECUs. A service tool that wants to gain access to the ECU for software reprogramming or service requests the ECU identification value and a challenge from the ECU and sends them to the secure server, which then identifies the security key value associated with that ECU identification value and the response for the challenge. The secure server then sends the response to the service tool, which provides it to the ECU to unlock it for programming.