Paper 2018/1152

Improvements of Blockchain’s Block Broadcasting:An Incentive Approach

Qingzhao Zhang, Yijun Leng, and Lei Fan

Abstract

In order to achieve a truthful distributed ledger, homogeneous nodes in Blockchain systems will propagate messages on a P2P network so that they can synchronize the status of the ledger. Currently, blockchain systems target on achieving better scalability and higher throughput to support divergent applications which will lead to heavier message propagation, especially the broadcasting of blocks. The heavier traffic on the P2P network will cause longer latency of block synchronization, which may damage system consistency and expose the system to potential attacks. Even worse, when heavy communication consumes a lot of network capacity, nodes in the P2P network may not relay blocks to save their bandwidth. This may damage the efficiency of network synchronization. In order to alleviate the problems, we propose an improved block broadcasting protocol which elaborates block data sharding and financial incentive mechanisms. In the proposed scheme, a block is sliced into pieces in order to keep the network traffic smooth and speed up content delivery. Any node which relays a piece of the block will get benefits with financial rewards. By applying data sharding, our proposed scheme speed up the block broadcasting and therefore shorten the synchronization time by 90\%, which is shown in our simulation experiments. In addition, we carry out game theoretical analysis to prove that nodes are efficiently incentivized to relay blocks honestly and actively.