Over the holidays I attended the 28th Chaos Communication Congress, where one specific talk about the integrity of new digital rail control systems made a few headlines in Europe. Why headline grabbing? In several countries around the world rail companies are now rolling out a digital train switching system which makes use of GSM-R, a more secure version of 2G GSM systems. This system replaces the analog switching systems that, perhaps surprisingly, are still the dominant system for controlling trains.
The theme of Stefan Katzenbeisser’s talk at the congress was the security of the new system, including the danger that if encryption keys were some how accessed by unauthorized individuals, the entire system could be shut down. As part of the Security Engineering Group within the Computer Science Department at the Technical University of Darmstadt, Katzenbeisser made clear that under normal circumstances the system is secure, but the problem relates to encryption keys and when they are changed or downloaded to USB sticks. In such situations the risk exists that those keys could be intercepted and then used. What the professor does not suggest, though many media outlets like to run with the headline, is that the security flaws could lead to accidents or other damages. If the weakness were to be exploited it could lead to severe delays and make rail travel a headache.
The new GSM-R system allows traffic controllers and train drivers to talk to each other while also transmitting data like each train’s speed and location. This allows signalers to give the train permission to enter the next part of the track, in turn making trackside signals unnecessary. The technology is now being used in parts of Europe, Africa and Asia.
Image via Telegraph