Design And Implementation Of Highly Secure Blockchain System

As a new type of distributed service,blockchain has received continuous attention and research from all over the world.Due to its features of decentralization,tamperresistance,and traceability,blockchain has become a popular research area.Blockchain technology can break the barriers of traditional trust systems and naturally build trust for all parties.Today,it has developed from the underlying technology of digital currency to a blockchain service that can carry various distributed applications,and has been applied in many areas such as finance,supply chain,medical care,and education.At the same time,with the development and change of blockchain technology,the security of the blockchain system is facing a challenge.At present,security incidents involving blockchain occur from time to time,and research on blockchain security is still a research hotspot in academia.This thesis studies various key technologies of blockchain and analyzes the "Security Specification for Financial Distributed Ledger Technology" standard,which summarizes the security requirements of the ledger,consensus,and smart contract engine.Then the thesis designed and implemented a highly secure blockchain system from these security requirements:(1)This thesis designs and implements a node access mechanism that identifies node identity based on node certificates and uses a genesis block to unify network configuration to achieve access control to external nodes.(2)For the security requirements of the ledger,this thesis designs and implements a highly secure self-verifying block ledger,which ensures the consistency and correctness of the ledger data through checkpoints and block verification.On this basis,the envelope encryption process is Combined with the block ledger,it supports encrypted storage of ledger data to meet data confidentiality,consistency,and verifiability.(3)For the security requirements of the consensus mechanism,this thesis designs and implements a two-stage Po A consensus mechanism,which uses the Raft algorithm to realize the two processes of block distribution and voting.On this basis,the thesis designed the security mechanism for some scenarios to meet the consistency,defense,and finality of the consensus.(4)For the security requirements of the smart contract engine,this thesis designs and implements a Docker-based smart contract engine to manage and control the entire life cycle of smart contracts.In addition,it supports ABAC-based access control to meet the security of smart contracts.Finally,by building a four-node blockchain system test environment,this thesis tests and analyzes the system from three aspects: function,security,and performance.In the security test,by building special test cases and special network scenarios,security is carried out on the network,ledger,consensus,and contract engine.The test results show that the system can meet the security requirements proposed by the standard.and still has high performance.