Research On Consensus Algorithm Based On Consortium Blockchain

Consensus algorithm is the criterion for blockchain nodes to reach a consensus in a distributed environment.Different blockchain application scenarios use different consensus algorithms.With its simple implementation process and efficient consensus,Raft algorithm has become one of the classic consensus algorithms of alliance blockchain or private blockchain.However,Raft algorithm is not Byzantine-fault-tolerant and cannot resist the impact of malicious nodes on the consensus process.Therefore,Raft algorithm has high security requirements for application scenarios,and all nodes joining the Raft cluster must through strict identity authentication.In recent years,many researchers have proposed many improved Raft algorithms with Byzantine fault tolerance by integrating digital signature technology,group consensus mechanism or other consensus algorithms,but the communication complexity and computational overhead of most improved algorithms have increased significantly.To solve the above problems,this paper proposes an improved Raft algorithm based on verification group —— VG-Raft(Verification Group Raft).VG-Raft algorithm introduces the concept of node trust value,which is calculated based on the past behavior of the node.VG-Raft requires the cluster to select a specified number of nodes as Verifiers to form a verification group according to the node trust value and communication delay.All decisions of the cluster need to be verified by the verification group before they take effect.Through security analysis,we can find that VG-Raft can effectively prevent Byzantine nodes from interfering with the algorithm consensus process.At the same time,the performance comparison also confirms that VG-Raft has higher efficiency in Leader election,block consensus and so on.For the privacy protection and secure sharing of blockchain data,this paper designs a new blockchain secure storage and sharing scheme based on VG-Raft.Before consensus process starts,Leader and Verifiers generate their own private keys and a shared public key according to the identity-based distributed key generation scheme.Blockchain data can be broadcast and stored only after being encrypted with the shared public key.Blockchain data is only disclosed to Leader and Verifiers who participated in its verification process,which can provide privacy protection while ensuring data availability.In addition,in order to facilitate the node to find the specified data from the block ciphertext,this scheme integrates the searchable encryption scheme based on SHA256 to locate the block of the specified data through keywords ciphertext comparison.At the same time,SHA256 can ensure the privacy of keywords.The security analysis and performance analysis prove that this scheme can effectively guarantee the data integrity and privacy,and the computation time of this scheme in data encryption and decryption stages is significantly lower than other schemes.