Research On Agitation Attack In Bitcoin

Bitcoin is a popular electronic cryptocurrency,and has formed a complete financial ecosystem in recent years.As a cryptocurrency,bitcoin has received widespread attention from scholars at home and abroad in recent years.In terms of transaction security,bitcoin outperforms any previous electronic currency.Considering the amount of money involved,Bitcoin is clearly the primary target of the attacker.Therefore,recent research on the issue of blockchain security has attracted much attention.In fact,attackers can launch attacks to obtain unfair mining reward.The most famous mining attack is the selfish mining attack,which makes full use of the weaknesses of distributed consensus protocols.Through using game theory analysis,an improved selfish mining attack,termed Agitation Attack,and the corresponding defense methods are proposed in this thesis.Moreover,the Agitation Attack is formulized as a game theory model,and the dominant strategies and Nash equilibrium of the Agitation Attack game are discussed for several different attack scenarios.Through the quantitative analysis of expected reward,we find that when the computing power of attacker and the unfaithful miners meets certain conditions,the best strategy of the unfaithful miner is to cooperate with the Agitation Attackers.And when the corresponding conditions are satisfied,the Agitation Attack will gain more benefits than that of selfish mining.This thesis also extends Agitation Attack to faction attacks,and analyzes Agitation Attacks between multiple mining pools.It is found that in the case of multiple attackers in the network,that is,the blockchain generates multiple branches,when the corresponding conditions are met,the expected return of the Agitation Attacker is still higher than the selfish mining miners.This thesis also simulates and analyzes attacker's expected reward through experiments,and compares the expected reward with that of a selfish mining attacker.The simulation results show that the Agitation Attackers tend to cooperate with unfaithful miners with low computing power to increase their influence on block publishing in Bitcoin network.Moreover,in most cases,Agitation Attack is more profitable than selfish mining,even if the computing power of attacker is low.