Compressing the Bitcoin Blockchain using Incremental Snapshots

Blockchains are append-only data structures, meaning their size increases steadily. As of March 2021, new nodes connecting to the Bitcoin blockchain already need to synchronize and validate more than 330 GB of data. Already now, this is an issue for resource-constrained thin clients who lack the required download, storage, or computing capacities to achieve this. In future, this issue will become even more relevant when blockchain technology is applied to new domains like the Internet of Things (IoT). We propose a new blockchain architecture that addresses this issue. Our proposal relies on incremental snapshot blocks that allow new and occasionally used clients to synchronize with the current state of the blockchain efficiently. The snapshot blocks form a second linked blockchain and are secured by the blockchain consensus algorithm. In this paper, we describe the proposed architecture in detail and evaluate its storage-saving potential using the Bitcoin blockchain. The evaluations performed show that our design can reduce the volume of data that needs to be downloaded and stored by up to 98%, thus facilitating secure blockchain-based applications also on resource-constrained thin clients like smartphones, netbooks, or IoT devices.