Vertical Federated Learning Based on Consortium Blockchain for Data Sharing in Mobile Edge Computing

The data in Mobile Edge Computing(MEC)contains tremendousmarket value,and data sharing canmaximize the usefulness of the data.However,certain data is quite sensitive,and sharing it directly may violate privacy.Vertical Federated Learning(VFL)is a secure distributed machine learning framework that completes joint model training by passing encryptedmodel parameters rather than raw data,so there is no data privacy leakage during the training process.Therefore,the VFL can build a bridge between data demander and owner to realize data sharing while protecting data privacy.Typically,the VFL requires a third party for key distribution and decryption of training results.In this article,we employ the consortium blockchain instead of the traditional third party and design a VFL architecture based on the consortium blockchain for data sharing in MEC.More specifically,we propose a V-Raft consensus algorithm based on Verifiable Random Functions(VRFs),which is a variant of the Raft.The VRaft is able to elect leader quickly and stably to assist data demander and owner to complete data sharing by VFL.Moreover,we apply secret sharing todistribute the private key to avoid the situationwhere the training result cannot be decrypted if the leader crashes.Finally,we analyzed the performance of the V-Raft and carried out simulation experiments,and the results show that compared with Raft,the V-Raft has higher efficiency and better scalability.

Asymmetric Consortium Blockchain and Homomorphically Polynomial-Based PIR for Secured Smart Parking Systems

In crowded cities,searching for the availability of parking lots is a herculean task as it results in the wastage of drivers’time,increases air pollution,and traffic congestion.Smart parking systems facilitate the drivers to determine the information about the parking lot in real time and book them depending on the requirement.But the existing smart parking systems necessitate the drivers to reveal their sensitive information that includes their mobile number,personal identity,and desired destination.This disclosure of sensitive information makes the existing centralized smart parking systems more vulnerable to service providers’security breaches,single points of failure,and bottlenecks.In this paper,an Improved Asymmetric Consortium Blockchain and Homomorphically Computing Univariate Polynomial-based private information retrieval(IACB-HCUPPIR)scheme is proposed to ensure parking lots’availability with transparency security in a privacy-preserving smart parking system.In specific,an improved Asymmetric Consortium Blockchain is used for achieving secure transactions between different parties interacting in the smart parking environment.It further adopted the method of Homomorphically Computing Univariate Polynomial-based private information retrieval(HCUPPIR)scheme for preserving the location privacy of drivers.The results of IACB-HCUPPIR confirmed better results in terms of minimized computation and communication overload with throughput,latency,and response time with maximized drivers’privacy preservation.Moreover,the proposed fully homomorphic algorithm(FHE)was compared against partial-homomorphic encryption(PHE)and technique without encryption and found that the proposed model has quick communication in allocating the parking slots starting with 24.3 s,whereas PHE starts allocating from 24.7 s and the technique without encryption starts at 27.4 s.Thus,we ensure the proposed model performs well in allocating parking slots with less time and high security with privacy preservation.

A Consortium Blockchain Paradigm on Hyperledger-Based Peer-to-Peer Lending System

This paper focuses on how to use consortium blockchain to improve the regulation of peer-to-peer(P2 P) lending market. The partial decentralized consortium blockchain with limited pre-set nodes can well improve transparency and security, which is suitable for financial regulation. Considering irregularities of the P2P lending market, the Hyperledger-based Peer-to-Peer Lending System(HyperP2PLS) is proposed. First elaborate the application scenario and business logic of the system, where a national P2P Lending Trading Center will be established to integrate all transactions and information of P2P lending market. Then construct the system architecture consisting of the blockchain network, HTTP server, and applications. The algorithm of implementation process and the web application for users have been well illustrated. The performance analysis shows that HyperP2PLS can guarantee the reliability, safety, transparency and efficiency.

LRChain:data protection and sharing method of learning archives based on consortium blockchain

Learning archives management in traditional systems faces challenges such as inadequate security,weak tamper resistance,and limited sharing capabilities.To address these issues,this paper proposes LRChain,a method based on consortium blockchain,for lifelong learning archives data protection and sharing.LRChain employs a combination of on-chain and off-chain cooperative storage using a consortium chain and inter planetary file system(IPFS)to enhance data security and availability.It also enables fine-grained verification of learning archives through selective disclosure principles,ensuring privacy protection of sensitive data.Furthermore,an attributebased encryption(ABE)algorithm is utilized to establish authorized access control for learning archives,facilitating safe and trusted sharing.Experimental evaluations and security analyses demonstrate that this method exhibits decentralization,strong security,tamper resistance,and performs well,effectively meeting the requirements for secure sharing of learning archive data.

Redactable consortium blockchain with access control:Leveraging chameleon hash and multi-authority attribute-based encryption

A redactable blockchain allows authorized individuals to remove or replace undesirable content,offering the ability to remove illegal or unwanted information.Access control is a mechanism that limits data visibility and ensures that only authorized users can decrypt and access encrypted information,playing a crucial role in addressing privacy concerns and securing the data stored on a blockchain.Redactability and access control are both essential components when implementing a regulated consortium blockchain in real-world situations to ensure the secure sharing of data while removing undesirable content.We propose a decentralized consortium blockchain system prototype that supports redactability and access control.Through the development of a prototype blockchain system,we investigate the feasibility of combining these approaches and demonstrate that it is possible to implement a redactable blockchain with access control in a consortium blockchain setting.

A Trust-Based Hierarchical Consensus Mechanism for Consortium Blockchain in Smart Grid

As the smart grid develops rapidly,abundant connected devices offer various trading data.This raises higher requirements for secure and effective data storage.Traditional centralized data management does not meet the above requirements.Currently,smart grid with conventional consortium blockchain can solve the above issues.However,in the face of a large number of nodes,existing consensus algorithms often perform poorly in terms of efficiency and throughput.In this paper,we propose a trust-based hierarchical consensus mechanism(THCM)to solve this problem.Firstly,we design a hierarchical mechanism to improve the efficiency and throughput.Then,intra-layer nodes use an improved Raft consensus algorithm and inter-layer nodes use the Byzantine Fault Tolerance algorithm.Thirdly,we propose a trust evaluation method to improve the election process of Raft.Finally,we implement a prototype system to evaluate the performance of THCM.The results demonstrate that the consensus efficiency is improved by 19.8%,the throughput is improved by 12.34%,and the storage is reduced by 37.9%.

A Consensus and Incentive Program for Charging Piles Based on Consortium Blockchain

Charging piles are used for charging electric vehicles and are directly accessible to users in an energy internet entrance,while playing an important role in energy consumption.Currently,each enterprise constructs the center of operation and maintenance of their systems independently,along with their respective APP payment programs.This results in high operating costs,poor user experience,and low utilization rate of the pile,which limits the promotion and popularization of electric vehicles.To overcome this limitation,there is a need for a multi-center,fair,and transparent consortium blockchain,which can conform to the application requirements of a unified payment system and accommodate a range of diverse enterprise charging piles.In this paper,the design for a consensus and incentive program for consortium blockchain is presented.First,the application status of blockchain in an energy internet is described.Then,the logical structure and hierarchical model of the consortium blockchain are analyzed.Next,multicycle accounting and limiting the amount of accounting nodes in each round is presented to ensure the overhead of consensus remain constant.Finally,the accounting incentive mechanism and the bidding encouragement strategy based on“electric beans”are designed.

Raft Consensus Algorithm Based on Credit Model in Consortium Blockchain

As one of the underlying technologies of the blockchain,the consensus algorithm plays a vital role in ensuring security and efficiency.As a consensus algorithm for the private blockchain,Raft has better performance than the rest of the consensus algorithms,and it does not cause problems such as the concentrated hashing power,resource waste and fork.However,Raft can only be used in a non-byzantine environment with a small network size.In order to enable Raft to be used in a large-scale network with a certain number of byzantine nodes,this paper combines Raft and credit model to propose a Raft blockchain consensus algorithm based on credit model CRaft.In the node credit evaluation phase,RBF-based support vector machine is used as the anomaly detection method,and the node credit evaluation model is constructed.Then the Trust Nodes List(TNL)mechanism is introduced to make the consensus phase in a creditable network environment.Finally,the common node is synchronized to the consensus node to update the blockchain of the entire network.Experiments show that CRaft has better throughput and lower latency than the commonly used consortium blockchain consensus algorithm PBFT(Practical Byzantine Fault Tolerance).

UCBIS:An improved consortium blockchain information system based on UBCCSP

Blockchain technologies have been applied in many areas,from economics,the internet of things to the industrial internet.In order to solve the issue that the Hyperledger Fabric does not currently support Chinese Commercial Cryptographic(CCC)algorithms,we extended the Blockchain Cryptographic Service Provider(BCCSP)module in the Hyperledger Fabric by upgrading the original BCCSP module to support the CCC algorithms SM2 and SM3.Furthermore,we designed a transaction process by using UBCCSP(Upgraded BCCSP),and a new smart contract also has been presented.After that,an improved consortium blockchain information system based on UBCCSP named UCBIS(Consortium Blockchain Information System based on UBCCSP)is proposed.In the Hyperledger Fabric transaction process,the identity information and transaction data are protected by the SM2 and SM3 algorithms,moreover,SM3 is also used in the construction process of smart contracts.Our smart contracts reduce the total data amount and improve query efficiency.Finally,the information query system based on UBCCSP is implemented.After being tested and analyzed,the average time for every query is only 31.162 ms in the blockchain system,which has better performance and higher query efficiency.

Consortium blockchains-based deep deterministic policy gradient algorithm for optimal electricity trading among households

To achieve higher energy utilization and lower generation cost for renewable sources(e.g., wind and solar energy), much work has been focused on demand response in smart grid(SG). Nonetheless, most existing studies consider energy trading with utility company which results in high energy loss from high voltage to low voltage and privacy leakage. Besides, there are relatively few researches devoted to electricity scheduling and price optimum among households without a third party. To cope with these issues, a novel deep deterministic policy gradient(DDPG)-based energy trading method with consortium blockchain(DETCB) is introduced. Firstly, in order to enhance system security, executing energy transaction among households is on the basis of consortium blockchain, which leads to not only anonymous trade but also public account. Moreover, the primary target from the aspect of the system is apparently the maximal social welfare, thus exploiting an iterative decision-making method combined with DDPG algorithm by non-profit controllers to obtain optimal trading prices and carry out optimal electricity allocation. To this end, security analysis demonstrates that DETCB contributes to creating a secure, stable and trustful environment. Furthermore, the excellent performance concerning social welfare, algorithm efficiency, and transaction energy sum is shown by numerical results.

Cross-Domain Authentication Scheme Based on Blockchain and Consistent Hash Algorithm for System-Wide Information Management

System-wide information management(SWIM)is a complex distributed information transfer and sharing system for the next generation of Air Transportation System(ATS).In response to the growing volume of civil aviation air operations,users accessing different authentication domains in the SWIM system have problems with the validity,security,and privacy of SWIM-shared data.In order to solve these problems,this paper proposes a SWIM crossdomain authentication scheme based on a consistent hashing algorithm on consortium blockchain and designs a blockchain certificate format for SWIM cross-domain authentication.The scheme uses a consistent hash algorithm with virtual nodes in combination with a cluster of authentication centers in the SWIM consortium blockchain architecture to synchronize the user’s authentication mapping relationships between authentication domains.The virtual authentication nodes are mapped separately using different services provided by SWIM to guarantee the partitioning of the consistent hash ring on the consortium blockchain.According to the dynamic change of user’s authentication requests,the nodes of virtual service authentication can be added and deleted to realize the dynamic load balancing of cross-domain authentication of different services.Security analysis shows that this protocol can resist network attacks such as man-in-the-middle attacks,replay attacks,and Sybil attacks.Experiments show that this scheme can reduce the redundant authentication operations of identity information and solve the problems of traditional cross-domain authentication with single-point collapse,difficulty in expansion,and uneven load.At the same time,it has better security of information storage and can realize the cross-domain authentication requirements of SWIM users with low communication costs and system overhead.KEYWORDS System-wide information management(SWIM);consortium blockchain;consistent hash;cross-domain authentication;load balancing.

Directed Acyclic Graph Blockchain for Secure Spectrum Sharing and Energy Trading in Power IoT

Peer-to-peer(P2P)spectrum sharing and energy trading are promising solutions to locally satisfy spectrum and energy demands in power Internet of Things(IoT).However,implementation of largescale P2P spectrum sharing and energy trading confronts security and privacy challenges.In this paper,we exploit consortium blockchain and Directed Acyclic Graph(DAG)to propose a new secure and distributed spectrum sharing and energy trading framework in power IoT,named spectrum-energy chain,where a set of local aggregators(LAGs)cooperatively confirm the identity of the power devices by utilizing consortium blockchain,so as to form a main chain.Then,the local power devices verify spectrum and energy micro-transactions simultaneously but asynchronously to form local spectrum tangle and local energy tangle,respectively.Moreover,an iterative double auction based micro transactions scheme is designed to solve the spectrum and energy pricing and the amount of shared spectrum and energy among power devices.Security analysis and numerical results illustrate that the developed spectrum-energy chain and the designed iterative double auction based microtransactions scheme are secure and efficient for spectrum sharing and energy trading in power IoT.

基于区块链的医联体护理协同管理系统的设计与实现

目的:设计一种基于区块链的医联体护理协同管理系统,为实现医联体护理协同管理提供技术支持。方法:该系统基于联盟链的5层技术架构进行设计,通过Linux系统搭建Fabric开发环境及网络配置,采用智能合约和Java语言软件开发工具包实现用户界面操作,使用Bootstrap和Jquery等技术搭建前端Web界面、Spring Boot搭建系统后端,并通过加密算法、哈希运算、智能合约、共识机制等技术实现联盟链成员管理、业务管理、数据存储与共享、患者病历管理及平台监管5个功能模块。结果:该系统完善了优质护理资源下沉与连续性护理机制,重构了积分激励机制,促进了护理共生网络协同进化,并使多节点交互,形成了协同合力。结论:该系统顺应全新模式下医联体整合型护理服务的发展趋势,对提升护理核心竞争力等方面起到重要推动作用,同时为构建适用于医联体场景的区块链方案提供了借鉴。

基于变色龙哈希和可验证秘密共享的联盟链修改方法

区块链具有去中心化、不可篡改、可追溯等特征。现有的联盟链系统在数据上链后会全程留痕,当出现敏感信息或恶意数据时无法处理,或处理后区块链分叉、中断。针对这些问题,提出一种基于变色龙哈希和可验证秘密共享的联盟链数据修改方法。首先,把变色龙哈希的陷门再分配给身份节点,从而将发起修改者与实际修改者进行隔离;其次,为保证再分配值的正确性,将不同时间周期变色龙哈希所对应的数据设为可验证数据,用验证节点上传承诺到可验证数据,并用提案节点通过承诺验证秘密共享值;最后,为防止节点作恶,提出基于奖励金机制的数据纠正方法提高节点纠正作恶的积极性,降低作恶的可能。在中山大学区块链与智能金融研究中心InPlusLab开发的DApps数据集上进行实验的结果表明:当恶意节点数30个时,所提方法相较于用传统变色龙哈希修改联盟链数据的方法在处理恶意节点的效率方面提高了44.1%;当恶意数据量达到30条时,在处理恶意数据的时间上缩短了53.7%。

基于联盟式区块链的域名系统根区管理体系

当前互联网域名系统的中心化根体系伴随着长期的担忧:一方面担忧国家代码顶级域可能由于根权威职能被破坏而失控;另一方面担忧去中心化的根替代方案会导致域名空间分裂.上述担忧的根源在于当前和替代的根区管理在自治化和透明化上不足,导致对当前的根权威或替代方案的不信任.为解决上述问题,提出一种新的域名系统根区管理体系——根共识链,通过增强互信缓解各方担忧.根共识链中多个自治的注册局共同参与根区管理,每个注册局下辖国家代码顶级域和根服务器运营者,共同构建一个基于联盟式区块链的根区管理体系.根共识链在维护统一域名空间和唯一全球根权威的同时,通过根共识链管理者们建立根共同体提高自治性,通过区块链记录和执行各方协议以及根区操作提高透明性.基于现网科研测试床的实验结果表明,根共识链能够有效应对上述担忧,具有良好的可行性与实用性.

电力集合竞价交易环境下用户隐私保护方案研究

在电力集合竞价交易中,用户竞价信息存在被窃听或篡改等风险,这会导致用户隐私泄露,造成经济损失,影响交易系统的公平性和透明性,甚至会对电力系统的稳定运行造成影响。因此,确保用户安全地参与电力集合竞价交易成为亟待解决的问题。为此,提出了一种基于联盟链和无证书聚合签密的隐私保护方案。使用了假名技术,防止用户参与电力集合竞价交易市场时真实身份信息被泄露;使用了改进的无证书聚合签密和时释性加密算法,竞价信息通过加密后上传至联盟链,确保了竞价信息的安全;通过联盟链和智能合约实现了电力集合竞价交易市场的公平性和透明性,交易匹配结果通过共识后上传到联盟链,确保数据安全存储。性能分析和实验结果表明,本方案计算开销较低,同时满足交易系统所需的安全特性,适用于电力集合竞价交易环境。

基于可聚合PVSS和联盟链的密钥可公开验证MA-CP-ABE方案

针对基于门限的多机构密文策略属性基加密(MA-CP-ABE)存在属性颁发机构(AA)不可信、属性私钥正确性无法公开验证等问题,提出了一种基于可聚合PVSS和联盟链的密钥可公开验证MA-CP-ABE方案。基于ElGamal改进可聚合PVSS算法,实现系统主密钥分发的可公开验证;基于双线性映射和ElGamal加密,构造MA-CP-ABE属性私钥可公开验证方法,实现属性私钥及其子份额密文条件下的可公开验证;基于联盟链提出密钥可公开验证MA-CP-ABE方案,通过联盟链保证验证参数可信,通过智能合约实现自动化验证。正确性、机密性、鲁棒性和活性等分析表明,当总AA数量为n、门限值为t、恶意AA数量不超过t-1时,所提方案能够保证属性私钥的正确分发,且系统主密钥初始化的通信开销复杂度为O(tn)。

基于联盟链的跨组织数据交换操作一致性模型

在跨组织的数据共享与交换中,维护较强的操作一致性是实现有效的数据同步的重要技术保障。以区块链技术为基础,提出了一种提高跨组织数据交换操作一致性性能的模型,将联盟链作为写前日志,供数据库回溯未完成同步的数据,在联盟链中增设了指针结构,以降低回溯时长。同时,设计了链上存储请求的数据结构及共识算法,通过设置准入机制验证用户身份,保护数据安全以及用户隐私。最后通过仿真实验验证所提模型的有效性,并探讨了不同参数对相关性能指标的影响。结果表明,在不同的参数设定下,所提模型均能保障跨组织数据交换过程中的强一致性;且与基准模型相比,具有更高的请求执行效率;当链上数据量较大时,指针结构能够进一步提升模型性能。

基于双默克尔树区块结构的交易粒度联盟链修改方案

随着区块链技术的蓬勃发展,以区块链为底层架构的信息系统已应用于包括数字货币、供应链等众多领域。在监管和实际应用双重需求的驱动下,可修改区块链技术因能够进行安全且权责分明的数据治理而成为当前研究的热点。然而,目前的修改方案中仍然存在修改权限过度中心化、修改效率不高等问题。针对上述问题,提出了一种交易粒度联盟链账本修改方案,构建了双默克尔树区块结构,利用椭圆曲线加密和迪菲-赫尔曼秘钥交换技术将变色龙哈希陷门信息(即变色龙哈希私钥)加密存储在区块中,降低密钥分发的系统通信开销。在此基础之上,通过默克尔树将修改权与用户绑定,修改提案受权限节点投票审查,有效防止了修改权的滥用,进一步提高了区块链系统的监管问责能力。实验表明,该联盟链账本修改方案的算法执行速率整体达到毫秒级,并大幅降低了链上数据修改操作的额外开销。

基于联盟区块链的航空里程积分结算方法

为解决航空联盟公司里程积分结算的互信问题,研究基于联盟链的里程积分结算方法。提出基于智能合约的同态加密的里程结算方法,对里程值进行同态加密,实现交易信息链上保密存储。通过智能合约对比自证里程结算数据以及同态计算结果数据,识别联盟公司是否发布虚假结算结果,解决里程结算可信问题。在超级账本对该方法进行模拟测试,结果表明该方法链上结算数据完整并准确识别发布虚假结算结果公司,具有较好的性能和较高的安全性。