Hedera: A Permissionless and Scalable Hybrid Blockchain Consensus Algorithm in Multiaccess Edge Computing for IoT

Multiaccess edge computing (MEC) network, as one of the key infrastructures of IoT, provides cloud computing capabilities at the edge of the radio access network (RAN) by integrating telecommunication and IT services. Integrating blockchain into the MEC network can provide users with secure, private, and traceable edge computing services at the near end, thereby improving IoT security, privacy, and automated use of resources. Due to some characteristics of the MEC network, there are still some challenges to integrate blockchain and edge computing into one system, especially the consensus algorithm of blockchain. The resources of edge computing nodes are limited, and the scale of the network is constantly expanding. Therefore, the blockchain consensus algorithm for the MEC network should occupy as little computing resources as possible, be green, and be permissionless. This article proposes a permissionless and scalable consensus algorithm "Hedera" for MEC network, which has the advantages of permissionless, security, decentralization, scalability, and greenness. The Hedera consensus algorithm is a hybrid blockchain consensus algorithm that combines the permissionless Proof-of-Capacity algorithm and the permissioned asynchronous Byzantine algorithm. This article tests the fairness, throughput, scalability, latency, and resource consumption of the algorithm by developing and deploying a prototype system. The experimental results show that the Hedera algorithm proposed in this article is fair, the throughput reaches 13986.3 TPS, and the resource consumption is much lower than the PoW consensus. By analyzing its security and liveness, it can resist the sybil attack, nothing-at-stake attack, selfish mining attack, and message hijacking attack, and has good liveness.