Software defined radio (SDR) is a revolutionary technology that promises to alleviate the spectrum shortage problem and bring about improvements in spectrum utilization efficiency. Conventional radios are built using ASIC (application specific integrated circuit) technology. Changes to such devices require highly technical skills and specialized equipment, thus making unauthorized changes to the devices infeasible for most adversaries. The emergence of SDR technology raises new security implications. It is quite possible for adversaries to modify user services or reconfigure RF parameters of an SDR by revising its radio software. This raises serious questions among regulators, operators, and users about the security vulnerabilities in SDR systems. The current focus of the SDR research and standardization efforts is on preventive security measures based on cryptosystems. Preventive security measures are measures that secure the radio software download process or schemes that thwart the tampering of the software once it has been downloaded. Recent studies, however, have shown that the possibility of inappropriate operation of SDRs due to malicious software cannot be precluded. To address this concern, in this project, we study security issues that pose the greatest threat when an adversary is able to install malicious software or modify already installed software on an SDR, with particular focus on threats that cannot be addressed using cryptographic techniques. Specifically, the focus of the research is on studying security vulnerabilities in the PHY and MAC layers of SDR networks. This research serves a critical need in the SDR research community by addressing security issues that have not been studied previously. It is expected that the research findings from this project will benefit regulators, service providers, and manufacturers involved in SDR development.
