Addressing the TETRA System Backdoor Challenge Through Friendly Jamming

TETRA (Terrestrial Trunked Radio, formerly known as Trans-European Trunked Radio) is used worldwide for Radio Frequency (RF) communications by emergency services, militaries, transportation and for commercial use. TETRA systems have been in use since the 1990’s in critical infrastructure worldwide and are still being deployed in the US for use in new projects. One example is the deployment of TETRA in new Offshore Wind Farm installations which are new to the US and still mimic European standards and installations. Even though the TETRA standard has been around since the nineties, it is still relevant and important to secure. Many of these systems remain in service or are still being deployed without a solution to a recently discovered Air Interface Encryption (AIE) vulnerability. Voice and data transmitted by TETRA radio systems is Air Interface Encrypted to protect its confidentiality and integrity and prevent eavesdropping and man-in-the-middle type attacks. This paper presents a recently discovered vulnerability in one of TETRA’s Air Interface Encryption Algorithms, examines existing solutions, and explores the use of Friendly Jamming (FJ) techniques to solve this problem.