基于HotStuff的高效量子安全拜占庭容错共识机制

Efficient Quantum-secure Byzantine Fault Tolerance Consensus Mechanism Based on HotStuff

经典区块链中拜占庭容错共识机制使用的公钥数字签名在量子计算机的指数级加速下暴露出脆弱性,存在一定的安全风险。针对拜占庭容错共识机制不具有量子安全性的问题,提出了基于HotStuff的高效量子安全拜占庭容错共识机制EQSH(Efficient Quantum-Secured HotStuff)。首先,为解决现有无条件安全签名(Unconditionally Secure Signatures,USS)通信复杂度高的问题,提出了一种高效的多方环形量子数字签名(Efficient Multi-party Ring Quantum Digital Signatures,EMRQDSs)方案,该方案基于一种环形量子网络,在保证量子安全性、不可伪造性、不可抵赖性以及可转移性的同时,通信复杂度为O(n)。其次,为了消除量子敌手对门限签名的安全威胁,对HotStuff中使用的门限签名进行替换,提出了一种基于密钥分发中心的签名收集方案,该方案可以实现与门限签名同样的效果,通信复杂度为O(n),同时保证了量子安全性。最后,将上述两个方案相结合,应用于HotStuff中,提供了量子安全性;设计了一个起搏器保证了活性;简化了共识信息格式,使用流水线共识流程提高了共识效率。EQSH中没有使用量子纠缠等成本较高的技术,可在现有技术条件下实现,实用价值较高。相较于HotStuff,EQSH具有量子安全性。相较于其他非纠缠型量子安全拜占庭容错共识机制,EQSH首次将通信复杂度降为O(n),具有更佳的性能表现,且对于客户端量子线路数量的需求更低,有利于降低量子网络的架设成本。

The public-key digital signature used by Byzantine fault tolerance consensus mechanism in the classic blockchain exposes vulnerability to quantum computers that have the exponential acceleration of computing power,and therefore have security risks.To address the problem that the Byzantine fault tolerance consensus mechanism does not have quantum security,this paper proposes an efficient quantum secure Byzantine fault tolerance consensus mechanism based on HotStuff,known as EQSH(efficient quantum secure HotStuff).Firstly,an efficient multi-party ring quantum digital signatures(EMRQDSs)scheme is proposed to solve the problem of high complexity of unconditionally secure signatures(USS)communication.The scheme is based on a ring quantum network that guarantees post-quantum security,non-enforceability,non-repudiation,and transferability while the communication complexity is O(n).Secondly,the gated signature used in HotStuff is improved,instead,we propose an alternative scheme for post-quantum security,i.e.,a signature collection scheme based on a key distribution center,which could achieve the same effect as gated signature while guaranteeing post-quantum security with a communication complexity of O(n).Subsequently,the above two schemes are adopted in HotStuff to provide post-quantum security;a heartbeat is designed to ensure the activity;the consensus message format is simplified and the consensus efficiency is improved by using a pipelined consensus process.Costly techniques such as quantum entanglement are not used in EQSH,our scheme can be implemented under existing technology conditions and thusis of high practical value.Compared to HotStuff,EQSH has post-quantum security.Compared with other non-entangled quantum-secured Byzantine fault tolerance consensus mechanisms,EQSH reduces the communication complexity to O(n)for the first time and has better performance which requires less quantum circuit resourcesfor the client,which is beneficial to the construction of quantum networks.