While the intersection of blockchain and Industrial Internet of Things (IIoT) has received considerable research interest
lately, the conflict between the high resource requirements of blockchain and the generally inadequate performance of IIoT devices has
not been well tackled. On one hand, due to the introductions of mathematical concepts, including Public Key Infrastructure (PKI),
Merkle Hash Tree, and Proof of Work (PoW), deploying blockchain demands huge computing power. On the other hand, full nodes
should synchronize massive block data and deal with numerous transactions in peer-to-peer (P2P) network, whose occupation of
storage capacity and bandwidth makes IIoT devices difficult to afford. In this paper, we propose a lightweight blockchain system called
LightChain, which is resource-efficient and suitable for power-constrained IIoT scenarios. Specifically, we present a green consensus
mechanism named Synergistic Multiple Proof (SMP) for stimulating the cooperation of IIoT devices, and a lightweight data structure
called LightBlock (LB) to streamline broadcast content. Furthermore, we design a novel Unrelated Block Offloading Filter (UBOF) to
avoid the unlimited growth of ledger without affecting blockchain‚??s traceability. The extensive experiments demonstrate that LightChain
can reduce individual computational cost to 39.32% and speed up the block generation by up to 74.06%. In terms of storage and
network usage, the reductions are 43.35% and 90.55%, respectively.
Blockchain, Industrial Internet of Things, Distributed System, Consensus Mechanism, Data Filter.