Drive to increase car security

Remote central locking is among the most convenient aspects of modern motoring. Transmission of the radio signal that activates the system is not particularly secure, however. A new encryption technique increases security without draining the key’s battery.

Most drivers love the convenience of remote central locking - the car doors are locked or unlocked just by pressing a button on the key. These systems are not particularly secure, however, as a potential car thief can, for example, use an antenna to eavesdrop on the radio signal and create a second key from the captured data on a computer.

The reason for this weakness in security is that the algorithms which encrypt the signals sent from the key to the vehicle are not strong enough. Their code was broken about two years ago. Car manufacturers are therefore using new algorithms to make the radio key systems more secure.

But these algorithms too have a major disadvantage - they are symmetric, their codes are embedded in the key and in the car.

Also, the same coded information is embedded in numerous vehicles from the same production line. Once one code has been broken, numerous cars are at risk.

Research scientists at the Fraunhofer Institute for Secure Information Technology SIT in Garching have now used an asymmetric algorithm to develop a car key prototype for the first time.

The secret is only located in the car key and not in the car as well. Each car key incorporates a different code and this makes the encryption much more secure than when a symmetric algorithm is used. Until now the high computation intensity and associated high energy consumption posed a high barrier against the use of asymmetric algorithms. Now a small cryptographic chip that is particularly energy saving has been developed. In addition, a protocol which minimises computation effort and the amount of data that has to be transmitted has been developed.