Towards blockchain-enabled single character frequency-based exclusive signature matching in IoT-assisted smart cities

With the increasing viability of Internet of Things (IoT), more devices are expected to be connected in a smart city environment. It can provide many benefits for people's daily life, but is also susceptible to many security threats in practice. Intrusion detection systems (IDSs), especially signature-based IDSs, are one of the most commonly adopted security mechanisms to safeguard various network environments like IoT-assisted smart city against cyber attacks. The process of signature matching is a key limiting factor for a signature-based IDS, and the exclusive signature matching (ESM) was designed based on the observation that most network packets would not match any IDS signatures. However, exclusive signature matching like the single character frequency-based ESM may be vulnerable to some attacks in a hostile environment. To mitigate this issue, in this work, we propose a blockchain-enabled single character frequency-based ESM, which can build a verifiable database of malicious payloads via blockchains. In the evaluation, we investigate the performance of our approach under flooding and character padding attacks in both a simulated and a real IoT network environment. The results demonstrate the effectiveness of our approach in enhancing the robustness of single character frequency-based ESM against malicious traffic.