B++: A High-Throughput Proof-of-Work based Blockchain with Eventual Consistency

Blockchain plays an important role in a variety of fields because it enables peers to cooperate with each other in a decentralized database. In Bitcoin-like protocols, each block is always mined by all miners, which implies a design philosophy that all transactions should be protected with the highest security. As a result, the throughput is bounded in these protocols. In real-world applications, the security requirement of transactions differs. Therefore, we present B++, a scalable blockchain structure, which breaks the limits of blockchain security so that B++ can distribute system resources efficiently to confirm transactions with different requirements. In our analysis, we show that B++ inherits eventual consistency in Bitcoin-like protocols. Moreover, our open-source simulation indicates that the throughput of B++ can be more than 100 times greater than that of baseline approaches; besides, the number of timeout transactions in B++ can decrease by up to 70% than that in a Bitcoin-like blockchain.