Research On Blockchain Security And Application In Used-car Circulation

Bitcoin,which emerged after the 2008 global financial crisis,solved the doublespending problem through its unique blockchain technology,which has had a broad and far-reaching impact on the traditional financial industry.The idea of decentralization is intended to reduce people's intervention in the market behavior and fully respect the self-regulation of market and adaptability.Although various decentralized cryptocurrencies,represented by bitcoin,will not completely replace traditional currencies,but its peer-to-peer transactions,open data ledger,quantitative issuance against inflation,and low cost,no geographical restrictions and other advantages,are very suitable as a payment and settlement tool for global economic integration,regional economic integration and cross-industry cooperation,which can effectively shorten the trading process and reduce cost.The bitcoin system is built on the blockchain technology.Based on the unstructured Peer to Peer network,it is still the most mature and stable distributed decentralized application in this field.With the wide spread of bitcoin,blockchain technology has attracted the attention of countries all over the world.It involves cryptography,network technology,consensus mechanisms,and distributed storage and other aspects,and the ingenious combination of these contents provides a practical decentralized platform.Starting from the operation mechanism of the bitcoin system,this paper analyzes the principle of important components of the system to understand the blockchain technology.After mastering the principle of blockchain technology,the paper analyzes and summarizes it.The security problems faced by blockchain technology and the shortcomings in technology are mainly studied,and the application fields of blockchain technology are expanded.Among the cryptocurrency system based on the blockchain technology,security issues mainly include digital currency asset security and system security.After summarizing the characteristics and shortcomings of the system,this paper proposes a distributed denial-of-service attack mode,namely broadcast transaction attack.Among the existing cryptocurrency system based on mining mechanism,mining reward is still the main source of miners' income,transaction fee accounts for a very low proportion,and the cost of launching garbage transaction is close to zero,which is one of the important factors for the execution of broadcast transaction attack.In the choice of solution,this article follows the principle of not modifying the underlying design of the system,and enhances the system's ability to resist attacks from the perspective of limiting user behavior in the application layer.The experiment adopted the method of simulation,and implemented two kinds of clients,ordinary users and miners with Python language,to intuitively show the attack behavior,and to prevent and alleviate the threat of attack to the system by limiting the number of transactions initiated to the system by users in a fixed period.Through experiment and evaluation,it is found that restricting users' behavior in the application layer can reduce the influence of broadcast transaction attack to some extent and help the system return to normal state after being attacked.In terms of application area expansion,this paper proposes a blockchain-based solution based on information asymmetry,regulatory difficulties,information islands and other problems that have existed in used-car market of China for a long time.Based on the information generated at key points in the whole life cycle of the car and combined with the feedback knowledge provided by the information providers and beneficiaries in each stage,an open and transparent,convenient to use,multimaintenance,security and tamper-proof system is designed.The entire proposal is based on the Ethereum platform and is implemented in the 64-bit Ubuntu 16.04 system.The core module adopts two levels of structure: car registration management,car usage information recording and display.In the case of fully publicizing and transparently displaying the true information of the car,the car owner information is completely isolated to protect personal privacy.At the same time,the MD5 information fingerprint algorithm is integrated in the car usage record and display module to further strengthen the security of information inquiry and transmission.From the current status of technology development,the proposal may face some practical difficulties,but if the relevant information beneficiaries can cooperate fully,it is believed that the proposal will contribute to the prosperity of the car market.