Proof of Reputation: A Blockchain-Based Countermeasure to Defend Against Massive SSDF in Cognitive Radio Networks

The reliability and accuracy of cooperative spectrum sensing (CSS) in cognitive radio networks (CRNs) are highly dependent on the integrity of the shared spectrum sensing data. However, driven by selfishness and malicious intentions, secondary users (SUs) may launch SSDF attacks, resulting in the damage to the integrity of sensing data, which will seriously affect the performance of CRNs, especially under massive SSDF attacks. Therefore, a blockchain-based CSS model is firstly proposed and a reputation-based consensus mechanism, named proof of reputation (PoR), is designed to enable CSS to countermeasure massive SSDF attacks in an environmentally friendly manner while supporting the operation of blockchain. Secondly, a reputation evaluation scheme based on extended sensing time and transmission result is developed to evaluate the reputation of SUs. In addition, in order to maximize the recognition performance of SSDF attacks, a closed-form expression of the optimal decision threshold constrained by the misjudged probability of honest SU is derived. Finally, the effectiveness and superiority of the proposed PoR consensus algorithm against massive SSDF attacks are demonstrated by comparing the simulation with the existing solutions.