DeChain: A Blockchain Framework Enhancing Decentralization via Sharding

In a blockchain system, full nodes store all the history data generated by the whole network. As time goes by, the increasing data will place a heavy burden on the full nodes. Rational nodes may discard history data, which results in the decrease of the number of full nodes. Moreover, huge storage requirement prevents storage-constrained users from participating in the network. These factors weaken decentralization and are harmful to the whole blockchain network. In this paper, we propose a new shard-based blockchain framework called DeChain which distributes the blockchain database into different nodes in protocol level. Specifically, we design a new mechanism to shard the UTXOs into specific nodes and set special rules for transaction generation. Each node in DeChain is in charge of the verification of some specified transactions. We propose an RSA accumulator-based method to support inter-shards verification of transactions. With this framework, users can participate in the consensus of the whole network by only maintaining a small portion of blockchain database. This greatly reduces the storage burden and enhances the decentralization of blockchain network.