一种量子安全拜占庭容错共识机制

Quantum Secured-Byzantine Fault Tolerance Blockchain Consensus Mechanism

针对经典区块链共识机制面临量子计算机攻击的问题,提出了一种量子安全拜占庭容错共识机制。首先,对于公钥数字签名存在的安全隐患问题,采用QKD网络进行量子密钥分发,通过经典网络传输消息和签名等信息,提出了一种基于量子密钥分发(Quantum Key Distribution,QKD)和多线性哈希函数族的无条件安全签名方案(Multilinear Hash-Unconditionally Secure Signature,MH-USS),该方案中的签名具备不可伪造性、不可抵赖性以及可传递性,并且该方案可在现有设备上实现,具有较高的实用价值。然后,针对经典拜占庭容错共识机制PBFT共识效率相对较低的问题,提出了一种QS-BFT(Quantum-Secured Byzantine Fault Tolerance)共识机制。最后,通过增设“快速-标准”双共识模式以及允许节点对空区块投票的方式,减少系统通信次数并消除视图转换过程,使方案不仅具备安全性与活性,还能够有效降低消息复杂度,提高共识效率。对所提方案进行仿真实现与性能测试,结果表明,与改进后基于MH-USS签名方案的PBFT共识机制相比,所提方案吞吐量更高、时延更短。

Aiming at the problem that the classical blockchain consensus mechanism is under the threat of quantum computing attacks,a quantum-secured Byzantine fault tolerant consensus mechanism is proposed.Firstly,to solve the security threat of public key digital signature,this paper proposes a multilinear hash-unconditionally secure signature(MH-USS)signature scheme based on quantum key distribution(QKD)and multilinear hash function family.In this scheme,quantum keys are distributed through QKD network,messages and signatures are transmitted through classical network,and the simplified USS signature scheme is adopted as the main framework,combined with the family of multiple linear hash functions,to generate a new USS scheme.This signature scheme has the characteristics of unforgeability,non-repudiation and transferability.Moreover,this scheme can be implemented on existing equipment and has high practical value.Secondly,in view of the relatively low consensus efficiency of the classical Byzantine fault-tolerant consensus mechanism PBFT,this paper proposes the quantum secured-byzantine fault tolerance(QS-BFT)consensus mechanism.By adding“fast-normal”consensus mode and allowing nodes to vote on empty blocks,the system communication times are reduced and the view conversion process is avoided.It has been proved that this scheme not only guarantees the safety and liveness,but also effectively reduces message complexity and improves consensus efficiency.The simulation and performance test for this scheme indicate that the throughput of this scheme is higher and the delay is lower compared with the PBFT consensus mechanism which is based on the MH-USS signature scheme.