An incentive compatible reward sharing approach for shard-based blockchains

Abstract

Sharding is a way to solving the scalability problem in the blockchain. The sharding method uses traditional consensus algorithms, such as PBFT. In traditional consensus algorithms, network nodes can register blocks by working together. In these algorithms, an important issue is how to motivate group nodes to participate in the consensus algorithm so as not to cause collusion or free-riding. In this paper, we first examine the previous solutions that try to solve the incentive mechanism in sharding blockchain and show that these solutions do not consider the leader's role in involving other nodes in the consensus algorithm. By the game theory, we show that the leader for increasing his benefit prevents some nodes from participating in the consensus algorithm, which creates collusion. We propose a solution to motivate group nodes in the sharding method and by the game theory prove that this solution is incentive compatible and also does not causes any collusion.