Review on security, privacy, and performance issues of blockchain

As a cornerstone to build a low-cost trusted channel so as to achieve value interconnection, blockchain has been especially highlighted and intensive research has been conducted in recent years. Among other issues within blockchain, challenges on security, privacy, and performance have attracted most eyes. To pave the way to deal with the above challenges, a review of research particularly on blockchain security, privacy and performance issues was presented from the perspectives of technical principle, progress and mechanism. With understanding of blockchain hierarchy and operation principles, the security issues within the layers of peer-to-peer network, consensus mechanism and smart contract were analyzed, and the effectiveness of respective defence measures was evaluated. By analysing the threats to blockchain privacy, the various privacy-protection solutions were evaluated for different protection targets. By identifying the performance related factors, the state-of-the-art solutions on the on-chain and off-chain scaling techniques were discussed. To tackle the existing problems in security, privacy and performance, the possible solutions and directions of future research were proposed respectively. © 2021, Editorial Department of CIMS. All right reserved.