Distributed and Lightweight Software Assurance in Cellular Broadcasting Handshake and Connection Establishment

Abstract

With developments in OpenRAN and software-defined radio (SDR), the mobile networking implementations for radio and security control are becoming increasingly software-based. We design and build a lightweight and distributed software assurance scheme, which ensures that a wireless user holds the correct software (version/code) for their wireless networking implementations. Our scheme is distributed (to support the distributed and ad hoc networking that does not utilize the networking-backend infrastructure), lightweight (to support the resource-constrained device operations), modular (to support compatibility with the existing mobile networking protocols), and supports broadcasting (as mobile and wireless networking has broadcasting applications). Our scheme is distinct from the remote code attestation in trusted computing, which requires hardwarebased security and real-time challenge-and-response communications with a centralized trusted server, thus making its deployment prohibitive in the distributed and broadcasting-based mobile networking environments. We design our scheme to be prover-specific and incorporate the Merkle tree for the verification efficiency to make it appropriate for a wireless-broadcasting medium with multiple receivers. In addition to the theoretical design and analysis, we implement our scheme to assure srsRAN (a popular open-source software for cellular technology, including 4G and 5G) and provide a concrete implementation and application instance to highlight our scheme’s modularity, backward compatibility to the existing 4G/5G standardized protocol, and broadcasting support. Our scheme implementation incorporates delivering the proof in the srsRAN-implemented 4G/5G cellular handshake and connection establishment in radio resource control (RRC). We conduct experiments using SDR and various processors to demonstrate the lightweight design and its appropriateness for wireless networking applications. Our results show that the number of hash computations for the proof verification grows logarithmically with the number of software code files being assured and that the verification takes three orders of magnitude less time than the proof generation, while the proof generation overhead itself is negligible compared to the software update period.