Design And Implementation Of Blockchain System Based On Proof Of Contribution Consensus Mechanism

The consensus mechanism is the core of the blockchain system.The current mainstream consensus mechanisms include PoW(Proof of Work),PoS(Proof of Stake),DPoS(Delegated Proof of Stake),etc.However,these consensus mechanisms have their own limitations.For example,PoW consensus mechanism requires a lot of energy.In PoS consensus mechanism,most of the tokens are owned by a few people,causing serious centralization.The selection of miners in the DPoS consensus mechanism relies on shareholders,so the consensus is controlled by a few people.Therefore,designing an energy-friendly,more decentralized,safer and more efficient consensus mechanism is a subject worth studying.In response to the above problems,the consensus mechanism based on the Proof of Contribution(PoC)adopts the method of selecting committees,and the block is mined by node within the committee,and no calculation is needed,which can solve the problem of energy consumption in PoW.The PoC consensus mechanism proposes a consensus committee selection method based on the contribution value of smart contracts.By counting the number of tokens transferred to the smart contract,the top N smart contracts are selected,and the deployers of these smart contracts constitute a consensus committee,thus the problem of committee selection centralization in DPoS can be solved.Finally,the PoC consensus mechanism proposes a proportional incentive method based on the smart contract contribution,which is based on the reward coefficient of the current committee epoch and the contribution value of the smart contract,which solves the problem of token hoarding in PoS.The Contribution-Rewarded Blockchain System(CRBS)is implemented based on the PoC consensus mechanism.Through security analysis,CRBS can defend against sybil attack,selfish mining and fork attack.The test results show that CRBS can process about 1000 transactions per second.