HOPE Number Nine (2012): "Practical Insecurity in Encrypted Radio" (Download)

Saturday, July 14, 2012: 12:00 pm (Sassaman): APCO Project 25 ("P25") is a suite of wireless communications protocols used in the United States and elsewhere for public safety two-way (voice) radio systems. The protocols include security options in which voice and data traffic can be cryptographically protected from eavesdropping. This talk analyzes the security of P25 systems against passive and active adversaries. The panel found a number of protocol, implementation, and user interface weaknesses that routinely leak information to a passive eavesdropper or that permit highly efficient and difficult to detect active attacks. They found new "selective subframe jamming" attacks against P25, in which an active attacker with very modest resources can prevent specific kinds of traffic (such as encrypted messages) from being received, while emitting only a small fraction of the aggregate power of the legitimate transmitter. And, more significantly, they found that even passive attacks repre