| Blockchain is a brand new network technology.Blockchain has the characteristics of decentralization,openness,autonomy,security,and trustworthiness,anonymity,good auditing performance,and programmability.Blockchain technology can help people build electronic money,programmable finance,and programmable society.The Bitcoin platform is the first blockchain platform and the largest blockchain platform with the most users.However,due to the use of the NTP time protocol in the existing Bitcoin platform,the difference between the time of the Bitcoin block and the actual time can be as long as 2 hours.This aspect makes the Bitcoin platform more vulnerable to time fraud forgery attacks and selfish mining attacks,thereby increasing the feasibility of malicious attackers implementing double payment attacks.On the other hand,the product traceability system and digital certificate system based on the Bitcoin platform depend to a certain extent on the block time on the Bitcoin platform,resulting in these traceability systems,The inaccuracy of the digital certificate system.In view of the security problems caused by timestamps in the current Bitcoin system,this paper first analyzes the principles of the existing Bitcoin timestamp service mechanism and its existing security threats.Secondly,to solve these security threats,an optimized blockchain timestamp mechanism is designed.The mechanism will participate in the consensus algorithm for new block generation by introducing an external trusted timestamp as the standard timestamp for the entire system.The new mechanism can reduce the legal interval of Bitcoin timestamps from the current 2 hours to an average of about 10 minutes.Finally,this paper analyzes the security and performance optimization of the program to show that the timestamp service mechanism proposed in this paper can effectively prevent time-jacking attacks and selfish mining on the basis of not reducing the operating efficiency of the existing Bitcoin platform. |
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