Sponsored Bitcoin Mining Pool Attack SFAW

All Bitcoin transaction history is stored in the form of blockchain,and the security of the blockchain based on cryptography determines the stability and security of the Bitcoin network.The blockchain accounting method driven by the consensus mechanism of Proof of Work(Po W)is one of the mainstream incentive mechanisms of existing digital cryptocurrencies(including Bitcoin).However,the security and sustainability of the Po W consensus mechanism is still an important research topic in related fields,especially when more and more miners spontaneously gather for mining pools to conduct mining activities in order to seek more stable mining income.The additional mining pool revenue rules introduced to manage mining pools underestimate the influence of the destructive behavior of rational miners and malicious miners,which brings great hidden dangers to the safe operation of the Bitcoin network.Numerous studies have shown that block withholding or malicious forks targeting mining pools can yield more benefits than honest mining.This thesis proposes a new attack model,Sponsored Fork After Withholding(SFAW)based on sponsorship.Compared to the three roles of previous attacks(i.e.attacker,victim pool,and remaining honest miners),SFAW attack introduces a new role called colluding pool.In the SFAW attack,the colluding pool establishes contact with the attacker and reaches a consensus on protection without directly violating the mining rules,and achieves mutual benefit by further damaging the reward of the victim pool and the other miners.This thesis compares the SFAW attack and the FAW attack.The relevant theoretical analysis and simulation results show that the attacker's income in the SFAW attack is higher than that in the FAW attack.Another important research conclusion is that both the attacker and the colluding pool can obtain more benefits in SFAW attack than in FAW attack,that is,a win-win situation.SFAW attack also maintains the advantage of FAW attack that can avoid miners' dilemma in the attack game,which makes SFAW attack expected to become the preferred attack strategy of attackers in Bitcoin mining pools.In order to make our theoretical analysis closer to the actual operating state of the Bitcoin network,this thesis studies and analyzes the dynamic gains in the process of SFAW attacks,that is,considering the impact of infiltrating miners' computing power on the adjustment of the mining difficulty of the system.We found that SFAW attackers can further boost their average gains by launching attacks intermittently.However,there are still many factors that affect the mining difficulty of the system.This article only considers the impact of the computing power of infiltrating miners on the mining difficulty.We will make a detailed comparative analysis of other influencing factors as future work.