船联网(internet of vehicle,IoS)是船舶信息交换的载体.基于区块链技术,在IoS上构建一种可信的信息交换机制,并提出相应的航行事件置信度计算与船舶信誉管理方案.该方案借鉴信息过滤的思想得到船舶综合相似度,利用加权熵值反向计算融...船联网(internet of vehicle,IoS)是船舶信息交换的载体.基于区块链技术,在IoS上构建一种可信的信息交换机制,并提出相应的航行事件置信度计算与船舶信誉管理方案.该方案借鉴信息过滤的思想得到船舶综合相似度,利用加权熵值反向计算融合的评级,根据回应船舶评级偏离融合评级的程度更新回应船舶的信誉值;然后采用最小二乘法建立信誉值倒数与评级误差之间的拟合关系,从而得以更新报告船舶的信誉值;进一步设计基于船舶信誉值的DPoS(delegated proof of stake)共识机制,旨在优先选择信誉值较高的船舶作为见证者船舶,以保障系统出块环境的稳定性和高效性.结果显示,在船舶滥用行为占比为40%的情况下,航行事件真实性判定的准确率仍在75%以上.研究表明,所提出的方案不仅有效提高了航行事件真实性判定的准确率,还能识别恶意船舶并限制其滥用行为,从而保证IoS环境的安全和稳定.展开更多
基于演化博弈将监察机制与奖惩制度引入授权股份证明(delegated proof of stake,DPoS)共识机制,构建以代理节点、投票节点、监管节点为主体的三方演化博弈模型;分析共识方案改进前后节点的行为策略选择变化,在不同奖惩力度和惩罚因子下...基于演化博弈将监察机制与奖惩制度引入授权股份证明(delegated proof of stake,DPoS)共识机制,构建以代理节点、投票节点、监管节点为主体的三方演化博弈模型;分析共识方案改进前后节点的行为策略选择变化,在不同奖惩力度和惩罚因子下节点行为策略的演化趋势,并用Matlab仿真。研究结果表明:(1)改进方案能遏制恶意节点的合谋行为并提高投票节点的积极性;(2)奖惩力度能影响节点行为策略;(3)惩罚因子可以影响节点行为趋向稳定点的速度。展开更多
委托权益证明(Delegate Proof of Stake, DPoS)通过投票选择见证人节点出块,实现了交易的快速认证,但其仍存在选择得到的见证人节点无法满足多数投票节点意愿、投票结果易被恶意节点操纵的问题,影响了DPoS的公平性与安全性.为此,本文将...委托权益证明(Delegate Proof of Stake, DPoS)通过投票选择见证人节点出块,实现了交易的快速认证,但其仍存在选择得到的见证人节点无法满足多数投票节点意愿、投票结果易被恶意节点操纵的问题,影响了DPoS的公平性与安全性.为此,本文将投票节点偏好的一致性作为选择见证人节点的指标,提出一种基于Kendall tau距离的DPoS记账权分配方法-DPoSKD (DPoS with Kendall tau distance).方法首先考虑到投票节点偏好不完整的问题,通过扩展Kendall tau距离定义以衡量不完整偏好间的一致性程度,然后将记账权分配过程建模为一个寻找与所有投票节点偏好一致性最大化的Top-k候选节点排列最优化问题,最后通过遗传算法来求解该优化问题,得到的Top-k候选节点作为见证人节点负责出块.实验结果表明通过该方法选择的见证人节点符合多数投票节点的意愿,提高了DPoS的公平性.同时,该方法具备更强的抗操纵性能,提升了DPoS的安全性.展开更多
针对授权股权证明共识机制中节点投票不积极和节点腐败的问题,提出一种基于配对制度的DPoS共识机制(delegated proof-of-stake based on matching mechanism,DPoS-M2)。根据节点属性值将节点分为独立节点、主节点和配基节点,通过主节点...针对授权股权证明共识机制中节点投票不积极和节点腐败的问题,提出一种基于配对制度的DPoS共识机制(delegated proof-of-stake based on matching mechanism,DPoS-M2)。根据节点属性值将节点分为独立节点、主节点和配基节点,通过主节点和配基节点配对增加节点间相互作用力,提高各类节点参与共识的积极性,从而降低系统中心化程度。采用类别评定模块,计算节点行为权重值并更新节点类别,使系统对节点的奖惩更具有针对性。当新节点加入系统时,运用马氏距离计算公式求出最需要该节点的社区,以保证社区动态且平衡运行。在仿真环境下,DPoS-M2在运行了80 min时,与DDPoS、DPoS-PI和DPoS相比,节点的参与度分别提高21.9%、8.7%和32.4%;出块数量分别提高63.2%、44.8%和11.6%;新节点参与率分别提高22.8%、25.5%和28.7%;恶意节点的剔除速度分别提高12%、32%和48%。实验结果表明,DPoS-M2能有效地提高节点的积极性和系统去中心化程度,加快出块速度,提高可扩展性,增强系统安全性。展开更多
针对委托权益证明(delegated proof of stake,DPoS)共识机制中节点作恶以及如何降低恶意节点成为代表节点可能性的问题,结合埃欧塔(IOTA)共识机制在安全性和稳定性方面的优势建立了节点之间的信任关系,提出了一种基于节点权重的DPoS(del...针对委托权益证明(delegated proof of stake,DPoS)共识机制中节点作恶以及如何降低恶意节点成为代表节点可能性的问题,结合埃欧塔(IOTA)共识机制在安全性和稳定性方面的优势建立了节点之间的信任关系,提出了一种基于节点权重的DPoS(delegated proof of stake based on node weight,NW-DPoS)共识算法。将节点历史行为信息、自身权重值和在线状态作为计算认可度的因素,选取累积认可度高的节点作为区块生产者;根据节点行为表现并以降低节点累积认可度的方式惩罚有恶意行为的节点。仿真实验和分析表明:NW-DPoS共识算法能够明显降低恶意节点成为代表节点的概率,并且在抵御双花攻击和贿赂攻击方面比DPoS共识机制更可靠,从而提高了系统的安全性。展开更多
Delegated blockchain governance is the frontier of blockchain design issues that is to improve the scalability of blockchain networks.Delegated proof of stake(DPoS)blockchains such as EOS must select a few super nodes...Delegated blockchain governance is the frontier of blockchain design issues that is to improve the scalability of blockchain networks.Delegated proof of stake(DPoS)blockchains such as EOS must select a few super nodes for transaction verification.In particular,the blockchain community has debated recently on whether dividend should be allowed when electing super nodes,which might be considered as unethical or unfair,leading to an open research topic and a new research gap that has theoretical value for both academia and industry.In this paper,we build a theoretical framework to study how dividend affects user decisions and welfare in a DPoS blockchain.Based on game theory,we propose a three-player Hotelling model with two policies to study the behaviors of voters and candidates.We first use a static game analysis to show that the benefits of dividend for voters and for candidates vary with the size of reward and there exists an interval,in which the zero dividend policy would be good for the welfare of both candidates and voters.Then,we use an evolutionary game analysis to examine the process dynamics of super node selection,we find that the campaign strategy of candidates has to do with the size of platform reward given to the candidates by the blockchain platform.Especially in the asymmetric case,we find that higher level of platform reward turns to benefit candidates with large number of votes even more.Our findings are instrumental for designing dividend policies in DPoS blockchains and can stimulate more potential research in blockchain governance.展开更多
文摘船联网(internet of vehicle,IoS)是船舶信息交换的载体.基于区块链技术,在IoS上构建一种可信的信息交换机制,并提出相应的航行事件置信度计算与船舶信誉管理方案.该方案借鉴信息过滤的思想得到船舶综合相似度,利用加权熵值反向计算融合的评级,根据回应船舶评级偏离融合评级的程度更新回应船舶的信誉值;然后采用最小二乘法建立信誉值倒数与评级误差之间的拟合关系,从而得以更新报告船舶的信誉值;进一步设计基于船舶信誉值的DPoS(delegated proof of stake)共识机制,旨在优先选择信誉值较高的船舶作为见证者船舶,以保障系统出块环境的稳定性和高效性.结果显示,在船舶滥用行为占比为40%的情况下,航行事件真实性判定的准确率仍在75%以上.研究表明,所提出的方案不仅有效提高了航行事件真实性判定的准确率,还能识别恶意船舶并限制其滥用行为,从而保证IoS环境的安全和稳定.
文摘基于演化博弈将监察机制与奖惩制度引入授权股份证明(delegated proof of stake,DPoS)共识机制,构建以代理节点、投票节点、监管节点为主体的三方演化博弈模型;分析共识方案改进前后节点的行为策略选择变化,在不同奖惩力度和惩罚因子下节点行为策略的演化趋势,并用Matlab仿真。研究结果表明:(1)改进方案能遏制恶意节点的合谋行为并提高投票节点的积极性;(2)奖惩力度能影响节点行为策略;(3)惩罚因子可以影响节点行为趋向稳定点的速度。
文摘委托权益证明(Delegate Proof of Stake, DPoS)通过投票选择见证人节点出块,实现了交易的快速认证,但其仍存在选择得到的见证人节点无法满足多数投票节点意愿、投票结果易被恶意节点操纵的问题,影响了DPoS的公平性与安全性.为此,本文将投票节点偏好的一致性作为选择见证人节点的指标,提出一种基于Kendall tau距离的DPoS记账权分配方法-DPoSKD (DPoS with Kendall tau distance).方法首先考虑到投票节点偏好不完整的问题,通过扩展Kendall tau距离定义以衡量不完整偏好间的一致性程度,然后将记账权分配过程建模为一个寻找与所有投票节点偏好一致性最大化的Top-k候选节点排列最优化问题,最后通过遗传算法来求解该优化问题,得到的Top-k候选节点作为见证人节点负责出块.实验结果表明通过该方法选择的见证人节点符合多数投票节点的意愿,提高了DPoS的公平性.同时,该方法具备更强的抗操纵性能,提升了DPoS的安全性.
文摘针对授权股权证明共识机制中节点投票不积极和节点腐败的问题,提出一种基于配对制度的DPoS共识机制(delegated proof-of-stake based on matching mechanism,DPoS-M2)。根据节点属性值将节点分为独立节点、主节点和配基节点,通过主节点和配基节点配对增加节点间相互作用力,提高各类节点参与共识的积极性,从而降低系统中心化程度。采用类别评定模块,计算节点行为权重值并更新节点类别,使系统对节点的奖惩更具有针对性。当新节点加入系统时,运用马氏距离计算公式求出最需要该节点的社区,以保证社区动态且平衡运行。在仿真环境下,DPoS-M2在运行了80 min时,与DDPoS、DPoS-PI和DPoS相比,节点的参与度分别提高21.9%、8.7%和32.4%;出块数量分别提高63.2%、44.8%和11.6%;新节点参与率分别提高22.8%、25.5%和28.7%;恶意节点的剔除速度分别提高12%、32%和48%。实验结果表明,DPoS-M2能有效地提高节点的积极性和系统去中心化程度,加快出块速度,提高可扩展性,增强系统安全性。
文摘针对委托权益证明(delegated proof of stake,DPoS)共识机制中节点作恶以及如何降低恶意节点成为代表节点可能性的问题,结合埃欧塔(IOTA)共识机制在安全性和稳定性方面的优势建立了节点之间的信任关系,提出了一种基于节点权重的DPoS(delegated proof of stake based on node weight,NW-DPoS)共识算法。将节点历史行为信息、自身权重值和在线状态作为计算认可度的因素,选取累积认可度高的节点作为区块生产者;根据节点行为表现并以降低节点累积认可度的方式惩罚有恶意行为的节点。仿真实验和分析表明:NW-DPoS共识算法能够明显降低恶意节点成为代表节点的概率,并且在抵御双花攻击和贿赂攻击方面比DPoS共识机制更可靠,从而提高了系统的安全性。
基金The authors acknowledge the support of research funds from the National Natural Science Foundation of China under Grant Nos.U1811462,71850013,91846301,72031001 and 71932002Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China under Grant No.151082+1 种基金Shenzhen Special Fund for Strategic Emerging Industries Development under Grant No.JCYJ20170818100156260Hong Kong ITF Fund under Grant No.GHP/142/18GD and National Key R&D Program of China under Grant No.2017YFC1601903.
文摘Delegated blockchain governance is the frontier of blockchain design issues that is to improve the scalability of blockchain networks.Delegated proof of stake(DPoS)blockchains such as EOS must select a few super nodes for transaction verification.In particular,the blockchain community has debated recently on whether dividend should be allowed when electing super nodes,which might be considered as unethical or unfair,leading to an open research topic and a new research gap that has theoretical value for both academia and industry.In this paper,we build a theoretical framework to study how dividend affects user decisions and welfare in a DPoS blockchain.Based on game theory,we propose a three-player Hotelling model with two policies to study the behaviors of voters and candidates.We first use a static game analysis to show that the benefits of dividend for voters and for candidates vary with the size of reward and there exists an interval,in which the zero dividend policy would be good for the welfare of both candidates and voters.Then,we use an evolutionary game analysis to examine the process dynamics of super node selection,we find that the campaign strategy of candidates has to do with the size of platform reward given to the candidates by the blockchain platform.Especially in the asymmetric case,we find that higher level of platform reward turns to benefit candidates with large number of votes even more.Our findings are instrumental for designing dividend policies in DPoS blockchains and can stimulate more potential research in blockchain governance.
