Abstract
The Internet of Things (IoT) is a technology enabler for enhancing the urban physical infra-structure and providing public services. However, public access to collected heterogeneous IoT urban data is more vulnerable to hackers invading intellectual property as all devices are con-nected to the internet. IoT security plays a vital role in the smart city. This IoT security is a real challenge as multiple goals and major inconveniences slow the rapid adaption of these smart devices. This paper presents a permissioned-based blockchain system that uses the arbiter PUF model to secure the key pairs of IoT devices using lightweight technology. A collaborative detection system is initially used to detect the DDoS on IoT devices using the machine learning -based ensemble technique, which provides a lower false-positive rate and better detection rate than the other classification technique. Next, we incorporated the blockchain system that securely shares the alarm alerts to all the nodes of the IoT network with adequately secured authentication.