LeapChain: Efficient blockchain verification for embedded IoT

Blockchain provides decentralized consensus in large, open networks without a trusted authority, making it a promising solution for the Internet of Things (IoT) to distribute verifiable data, such as firmware updates. However, verifying data integrity and consensus on a linearly growing blockchain quickly exceeds memory and processing capabilities of embedded systems. As a remedy, we propose a generic blockchain extension that enables highly constrained devices to verify the inclusion and integrity of any block within a blockchain. Instead of traversing block by block, we construct a LeapChain that reduces verification steps without weakening the integrity guarantees of the blockchain. Applied to Proof-of-Work blockchains, our scheme can be used to verify consensus by proving a certain amount of work on top of a block. Our analytical and experimental results show that, compared to existing approaches, only LeapChain provides deterministic and tight upper bounds on the memory requirements in the kilobyte range, significantly extending the possibilities of blockchain application on embedded IoT devices.