MSKNP: Multistage Key Negotiation Protocol for IoT-Blockchain Environment

With the development of the Internet, the technical framework that integrates Internet of Things (IoT) and blockchain has gradually developed. However, how to ensure the secure with balanced performance of devices becomes a key issue. In this article, we design a new multistage session key negotiation protocols for the Internet of Things-blockchain environment by using "Agents." We transfer bilinear operations to Agents, which has strong computing capabilities. Based on this, the resource of IoT devices in the key negotiation process is reduced without simplifying bilinear pairing compute and making them more secure. The simplified BPR model and the random oracle model ID-BJM are used to test the security of requirements in different stages of the scheme, furthermore, theoretically analyze its performance overhead. This protocol can reduce the computing overhead of IoT devices in the key negotiation process under the premise of ensuring security.