Hybrid Consensus Protocols and Security Analysis for Blockchain

Abstract

Blockchain shows the potential for various applications, thanks to its property of decentralization and its security. Consensus protocols play an important role in the blockchain system, especially in the security of the blockchain system. Moreover, hybrid consensus protocols were introduced to tackle the weaknesses of one consensus protocol. Therefore, this paper conducts a security performances analysis of the hybrid protocols, starting with the classification of mainstream consensus protocols, such as Proof-of-Work, Proof-of-Stake, Delegated-Proof-of-Stake, and Practical-Byzantine-Fault-Tolerance. This survey paper analyzes several common consensus security attacks and their target consensus protocols. Furthermore, this paper presents some hybrid protocol cases and explains common problems and the working mechanism of hybrid protocols. This paper further summarizes the security analysis of each case. The result indicates that hybrid protocols can handle particular security issues quite well since hybrid protocols can inherit the strengths from another consensus protocol that is not troubled by a particular security attack. Some future study directions are highlighted regarding hybrid protocol security performance in this paper, which are the great contribution made in this paper and will be valuable references for the related researchers.