Cars are travelling computers in which software controls key vehicle functions. With over 100 million lines of code, it is a challenge to keep the system up to date at all times and to implement new features. Regular security updates for firmware and software are absolutely essential. With over-the-air updates (OTA), vehicles no longer have to go into a garage for updates.
Automatic software updates over the Internet have been standard for years for laptops, telephones, and TV devices. In the automotive industry though, they are still relatively rare. Vehicle owners are usually called into garages to implement updates. The objective, then, is to employ methods that use wireless interfaces like WLAN or mobile communications. 2012 saw the first over-the-air updates, which mostly concerned non-critical infotainment functions. Some OEMs now regularly carry out over-the-air updates. These are usually still updates of systems not critical to safety, such as navigation maps or sound system changes. Mobile software updates for safety systems or functions that are directly connected to driving are only now being slowly realised. In future it may be that, thanks to new features that the OEM implements using over-the-air updates, vehicles will no longer decline in value. A benefit for customers and suppliers.
For OTA updates, a car needs either a SIM card or a WLAN network. Once a connection exists, an OTA manager launches the update process. An electronic control unit that is fitted with a mobile communications interface takes over the role of mediating between the back-end and the devices within the car that are to be updated. It receives all software packages via the air interface and distributes them via CAN bus systems. In addition, the electronic control unit (gateway TCU (Telematics Control Unit)) controls and coordinates the entire process as the master device.
The transfer of the data packages must be protected, as third parties could otherwise access important vehicle features. This means that safety and security are key aspects for success. Alongside encryption of the transmission channel, and the secure identification and authorisation of vehicles and their electronic control units, the protection of updates through package encryption and integrity checks plays a crucial role.