Efficient Blockchain-Based Mutual Authentication and Session Key Agreement for Cross-Domain IIoT

Several studies have introduced edge computing and blockchain into the Industrial Internet of Things (IIoT) to satisfy the requirements of delay-sensitive applications and support cross-domain authentication. Although there have been many protocols to ensure the security and privacy of devices in the IIoT, existing protocols still suffer from problems. Updating keys and pseudonyms of devices by a trusted third party (e.g., certificate authority) will cause high communication and computation overhead, especially when the number of devices becomes much larger. Furthermore, an increasing number of transactions also cause high storage overhead on the blockchain. Therefore, we propose a blockchain-based cross-domain authentication protocol. Specifically, we propose a privacy-preserving method based on pseudonyms that offloads the task of generating pseudonyms from a trusted third party to edge servers to ensure the conditional anonymity of the devices. The device is allowed to request pseudonyms in bulk to reduce the number of transactions, thus reducing the storage overhead on the blockchain. Security analysis and experimental results demonstrate that our scheme achieves an efficient tradeoff between security and efficiency.