Jamming-resistant Broadcast Communication without Shared Keys; ; ETH Zurich D-INFK Technical Report;

Jamming-resistant broadcast communication is crucial for many safety-critical applications such as emergency alert broadcasts or the dissemination of navigation signals in adversarial settings. Shared by these applications is the need for guaranteed authenticity and availability of messages which are broadcasted by base stations to a large and unknown number of (potentially untrusted) receivers. Common techniques to counter jamming attacks such as Direct-Sequence Spread Spectrum (DSSS) and Frequency Hopping are based on secrets that need to be shared between the sender and the receivers before the start of the communication. However, relying broadcast anti-jamming communication on either secret pairwise or group keys suffers from serious and sometimes even unsolvable scalability and keysetup problems or from weak jamming-resistance, respectively. In this work, we therefore propose a solution called Uncoordinated DSSS (UDSSS) that enables spread-spectrum anti-jamming broadcast communication without the requirement of shared secrets. It is applicable to broadcast scenarios in which receivers hold a certificate of the sender’s public key, but do not share a secret key with it. UDSSS can handle an unlimited amount of receivers while being secure against malicious receivers. We analyze the security and latency of UDSSS and complete our work by an experimental evaluation on a prototype implementation.