The purpose of the covert communication scheme is to conceal the communication behavior entirely.In such schemes,the sender and receiver rely on secret keys to establish a covert channel.However,conventional key excha...The purpose of the covert communication scheme is to conceal the communication behavior entirely.In such schemes,the sender and receiver rely on secret keys to establish a covert channel.However,conventional key exchange protocols would expose the key exchange process between them.An adversary who observes the key exchange would be aware of the existence of communication behavior.The keys used in covert communication are not suitable to be generated through conventional key exchange schemes.To address this,we propose a blockchain-based covert elliptic-curve Diffie-Hellman key exchange scheme(BCDH)to conceal the process of the key exchange in blockchain transactions.Following a straightforward setup,BCDH allows the sender and receiver to covertly exchange a secret key on a blockchain without direct communication.Furthermore,we expand the BCDH approach to operate across multiple blockchains,further enhancing its covertness and stability.We analyze BCDH from several perspectives,including covertness,security,randomness,etc.Additionally,we implement a prototype of BCDH on the Ethereum platform to assess its feasibility and performance.Our evaluation demonstrates that BCDH is efficient and well-suited for real-world applications.展开更多
The inter-agency government information sharing(IAGIS)plays an important role in improving service and efficiency of government agencies.Currently,there is still no effective and secure way for data-driven IAGIS to fu...The inter-agency government information sharing(IAGIS)plays an important role in improving service and efficiency of government agencies.Currently,there is still no effective and secure way for data-driven IAGIS to fulfill dynamic demands of information sharing between government agencies.Motivated by blockchain and data mining,a data-driven framework is proposed for IAGIS in this paper.Firstly,the blockchain is used as the core to design the whole framework for monitoring and preventing leakage and abuse of government information,in order to guarantee information security.Secondly,a four-layer architecture is designed for implementing the proposed framework.Thirdly,the classical data mining algorithms PageRank and Apriori are applied to dynamically design smart contracts for information sharing,for the purposed of flexibly adjusting the information sharing strategies according to the practical demands of government agencies for public management and public service.Finally,a case study is presented to illustrate the operation of the proposed framework.展开更多
跨链是一种打破区块链网络“信息孤岛”,实现不同区块链网络之间互操作的重要技术。作为跨链实现的产物,跨链桥已成为异构区块链之间实现资产转移和信息传递的重要解决方案。近几年,针对跨链桥漏洞的攻击频繁发生,攻击导致的跨链交易异...跨链是一种打破区块链网络“信息孤岛”,实现不同区块链网络之间互操作的重要技术。作为跨链实现的产物,跨链桥已成为异构区块链之间实现资产转移和信息传递的重要解决方案。近几年,针对跨链桥漏洞的攻击频繁发生,攻击导致的跨链交易异常已造成高达数十亿的经济损失。然而,目前对跨链桥的异常交易问题研究较少,且仅有的一些检测工作高度依赖于人工总结的交易序列异常模式。针对这一问题,提出一种基于BERT(Bidirectional Encoder Representations from Transformers)模型的跨链异常交易检测方法,通过提供基于特征提取的2种检测模式,克服现有检测方法对人工经验依赖的局限性。第1种模式旨在更精准地提取特征,先根据交易状态从跨链原生交易数据中自动抽取具有关键特征的跨链交易序列,再通过跨链交易序列文本数据微调BERT-Base-Uncased预训练模型适应异常交易检测任务;第2种模式旨在弥补仅考虑关键跨链交易序列可能带来的特征不足,直接通过具有全面特征的原始交易文本数据微调BERT-Base-Uncased预训练模型进而解决异常交易检测任务。实验使用现有工作的真实跨链数据评估所提检测方法,结果表明,2种检测模式均能有效检测出异常的跨链交易,精确率、召回率及F1值均达到了100%。展开更多
共识算法是一种用于确保区块链网络中所有节点达成一致的方法,常见的有工作量证明(Proof-of-Work,PoW)和权益证明(Proof of Stake,PoS)等,共识机制的优劣影响着区块链系统的性能。为了解决现有区块链共识算法存在的吞吐量较小、时延较...共识算法是一种用于确保区块链网络中所有节点达成一致的方法,常见的有工作量证明(Proof-of-Work,PoW)和权益证明(Proof of Stake,PoS)等,共识机制的优劣影响着区块链系统的性能。为了解决现有区块链共识算法存在的吞吐量较小、时延较长等问题,对区块链中实用拜占庭容错(PBFT)算法进行改进,引入基于Bayes理论的动态信任模型(Dynamic Trust Model),通过节点信任机制改变节点在共识轮中的信任度,并按照信任度进行分组等操作,在保证PBFT稳定性的同时提高了系统可扩展性,且完善了网络节点的加入退出机制,使得网络可拓展性得到提高。通过实验测试,相比传统PBFT,改进后的算法在吞吐量上有25%的提升,在节点数量达到50的情况下时延只有PBFT的一半,所提方法的这两项指标相比HotStuff算法和Paxos算法也有20%~30%的提升。展开更多
文摘The purpose of the covert communication scheme is to conceal the communication behavior entirely.In such schemes,the sender and receiver rely on secret keys to establish a covert channel.However,conventional key exchange protocols would expose the key exchange process between them.An adversary who observes the key exchange would be aware of the existence of communication behavior.The keys used in covert communication are not suitable to be generated through conventional key exchange schemes.To address this,we propose a blockchain-based covert elliptic-curve Diffie-Hellman key exchange scheme(BCDH)to conceal the process of the key exchange in blockchain transactions.Following a straightforward setup,BCDH allows the sender and receiver to covertly exchange a secret key on a blockchain without direct communication.Furthermore,we expand the BCDH approach to operate across multiple blockchains,further enhancing its covertness and stability.We analyze BCDH from several perspectives,including covertness,security,randomness,etc.Additionally,we implement a prototype of BCDH on the Ethereum platform to assess its feasibility and performance.Our evaluation demonstrates that BCDH is efficient and well-suited for real-world applications.
基金Supported by the Project of Guangdong Science and Technology Department(2020B010166005)the Post-Doctoral Research Project(Z000158)+2 种基金the Ministry of Education Social Science Fund(22YJ630167)the Fund project of Department of Science and Technology of Guangdong Province(GDK TP2021032500)the Guangdong Philosophy and Social Science(GD22YYJ15).
文摘The inter-agency government information sharing(IAGIS)plays an important role in improving service and efficiency of government agencies.Currently,there is still no effective and secure way for data-driven IAGIS to fulfill dynamic demands of information sharing between government agencies.Motivated by blockchain and data mining,a data-driven framework is proposed for IAGIS in this paper.Firstly,the blockchain is used as the core to design the whole framework for monitoring and preventing leakage and abuse of government information,in order to guarantee information security.Secondly,a four-layer architecture is designed for implementing the proposed framework.Thirdly,the classical data mining algorithms PageRank and Apriori are applied to dynamically design smart contracts for information sharing,for the purposed of flexibly adjusting the information sharing strategies according to the practical demands of government agencies for public management and public service.Finally,a case study is presented to illustrate the operation of the proposed framework.
文摘跨链是一种打破区块链网络“信息孤岛”,实现不同区块链网络之间互操作的重要技术。作为跨链实现的产物,跨链桥已成为异构区块链之间实现资产转移和信息传递的重要解决方案。近几年,针对跨链桥漏洞的攻击频繁发生,攻击导致的跨链交易异常已造成高达数十亿的经济损失。然而,目前对跨链桥的异常交易问题研究较少,且仅有的一些检测工作高度依赖于人工总结的交易序列异常模式。针对这一问题,提出一种基于BERT(Bidirectional Encoder Representations from Transformers)模型的跨链异常交易检测方法,通过提供基于特征提取的2种检测模式,克服现有检测方法对人工经验依赖的局限性。第1种模式旨在更精准地提取特征,先根据交易状态从跨链原生交易数据中自动抽取具有关键特征的跨链交易序列,再通过跨链交易序列文本数据微调BERT-Base-Uncased预训练模型适应异常交易检测任务;第2种模式旨在弥补仅考虑关键跨链交易序列可能带来的特征不足,直接通过具有全面特征的原始交易文本数据微调BERT-Base-Uncased预训练模型进而解决异常交易检测任务。实验使用现有工作的真实跨链数据评估所提检测方法,结果表明,2种检测模式均能有效检测出异常的跨链交易,精确率、召回率及F1值均达到了100%。
文摘共识算法是一种用于确保区块链网络中所有节点达成一致的方法,常见的有工作量证明(Proof-of-Work,PoW)和权益证明(Proof of Stake,PoS)等,共识机制的优劣影响着区块链系统的性能。为了解决现有区块链共识算法存在的吞吐量较小、时延较长等问题,对区块链中实用拜占庭容错(PBFT)算法进行改进,引入基于Bayes理论的动态信任模型(Dynamic Trust Model),通过节点信任机制改变节点在共识轮中的信任度,并按照信任度进行分组等操作,在保证PBFT稳定性的同时提高了系统可扩展性,且完善了网络节点的加入退出机制,使得网络可拓展性得到提高。通过实验测试,相比传统PBFT,改进后的算法在吞吐量上有25%的提升,在节点数量达到50的情况下时延只有PBFT的一半,所提方法的这两项指标相比HotStuff算法和Paxos算法也有20%~30%的提升。
