摘要： 联盟链是一种允许授权节点加入网络的区块链，当存在网络状况不理想等状况时，会出现节点动态加入退出的问题。为此，在环签名理论、ElGamal数字签名算法与PBFT算法的基础上，提出一种基于ElGamal数字签名算法的环签名改进方案。对环签名算法进行正确性及匿名性分析，运用环签名方案改进PBFT算法的签名及验证过程，使用Fabric中的区块链性能测试框架Caliper对改进方案进行性能测试，结果表明，基于环签名方案的改进PBFT共识算法可较好地解决网络中节点动态加入退出问题，且能够达到原PBFT算法的拜占庭节点容错率，具有一定的实用性。

关键词: 区块链, ElGamal算法, PBFT算法, 环签名, 共识算法

Abstract: The alliance chain is a kind of blockchain that allows authorized nodes to join in the network.However,when the network condition is poor,the nodes will join and exit dynamically.Therefore,on the basis of ring signature theory,ElGamal digital signature algorithm and PBFT algorithm,we propose a ring signature scheme based on ElGamal digital signature algorithm to cope with this problem.First,we analyze the correctness and anonymity of the ring signature algorithm.Then,we use the ring signature scheme to improve the signature and verification process of the PBFT algorithm.Finally,we adopt Caliper,the blockchain performance testing framework in Fabric,to test the performance of the improved scheme.Experimental results show that the improved,ring signature-based PBFT consensus algorithm can solve the dynamic joining and exiting problem of nodes in the network while reaching the fault-tolerant rate of the Byzantine node of the original PBFT algorithm,which has certain practical values.

Key words: blockchain, ElGamal algorithm, PBFT algorithm, ring signature, consensus algorithm

中图分类号: 

• TP309.7