A Blind Batch Encryption and Public Ledger-Based Protocol for Sharing Sensitive Data

For the goals of security and privacy preservation,we propose a blind batch encryption-and public ledger-based data sharing protocol that allows the integrity of sensitive data to be audited by a public ledger and allows privacy information to be preserved.Data owners can tightly manage their data with efficient revocation and only grant one-time adaptive access for the fulfillment of the requester.We prove that our protocol is semanticallly secure,blind,and secure against oblivious requesters and malicious file keepers.We also provide security analysis in the context of four typical attacks.

Distributed ledger technology for securities clearing and settlement: benefits, risks, and regulatory implications

This article outlines the benefits and risks of the distributed ledger technology(DLT)for the clearing and settlement of exchange-traded and OTC securities,followed by a description of the technology’s potential role for central counterparties and central securities depositories.Although the industry and scholars are attempting to solve the technological and operational issues that DLT systems still face,outstanding legal risks are such that the financial industry is asking for more regulatory guidance and intervention.This article wants to contribute to the public policy debate by presenting potential regulatory barriers that may have to be removed for DLT to be fully adopted.In addition,it identifies areas requiring an update of the legal framework in order to address certain prudential and conduct risks that this technology could introduce.

International Standardization of Blockchain and Distributed Ledger Technology:Overlaps,Gaps and Challenges

As one of the most concerned digital technologies in recent years,blockchain and distributed ledger technology are an important driving force for a new round of technological development.It is currently in the process of accelerating its evolution and maturity,and has gradually integrated with other digital technologies.It has been applied in many industries,providing decentralized solutions for various industries,realizing innovative storage models,and building a new trust system.As blockchain technology is officially incorporated into China’s new information infrastructure category,the application fields of blockchain have expanded rapidly,gradually extending from the financial field and government affairs to other fields in the real economy.At the same time,with the continuous development of the globalized economy,blockchain technology will also have a profound impact on international technological and economic development.Therefore,for the healthy and orderly development and real implementation of the blockchain industry,standardize the application of blockchain,effectively break through the cognitive and technical barriers between different countries,industries and systems on a global scale,prevent application risks,the development of the global blockchain industry needs standardization basis,which is particularly important and urgent.A sound standard system is an important key to the successful development of technology,and formulating the right standard at the right time for technology development helps ensure the ease of use and interoperability of the technology.From the perspective of international standardization,this article first introduces the general situation of ISO,ITU-T,IEEE,W3C and other international standardization organizations,and sorts out the status quo of the blockchain standardization working groups of mainstream international standardization organizations.All blockchain-related standards under development have been analyzed for the characteristics of international blockchain technology standards and industry application standards.Through data analysis,the overlaps,differences and conflicts in the field of international blockchain standard formulation are sorted out,and suggestions for blockchain standardization work in the application and development of blockchain technology standardization by international organizations and industries are put forward.The plans and layouts of future international standards are summarized to help the development of the international standardization of blockchain.

Privacy-preserving analytics for the securitization market: a zero-knowledge distributed ledger technology application

A zero-knowledge proof or protocol is a cryptographic technique for verifying private data without revealing it in its clear form.In this paper,we evaluate the potential for zero-knowledge distributed ledger technology to alleviate asymmetry of information in the asset-backed securitization market.To frame this inquiry,we conducted market data analyses,a review of prior literature,stakeholder interviews with investors,originators and security issuers and collaboration with blockchain engineers and researchers.We introduce a new system which could enable all market participants in the securitization lifecycle(e.g.investors,rating agencies,regulators and security issuers)to interact on a unique decentralized platform while maintaining the privacy of loan-level data,therefore providing the industry with timely analytics and performance data.Our platform is powered by zkLedger(Narula et al.2018),a zero-knowledge protocol developed by the MIT Media Lab and the first system that enables participants of a distributed ledger to run publicly verifiable analytics on masked data.

A Framework for e-Voting System Based on Blockchain and Distributed Ledger Technologies

Election allows the voter of a country to select the most suitable group of candidates to run the government.Election in Pakistan is simply paper-based method but some certain political and socio-economic issues turn that simple process in complicated and disputes once.Solutions of such problems are consisting of many methods including the e-voting system.The e-voting system facilitates the voters to cast their votes by electronic means with very easy and convenient way.This also allows maintaining the security and secrecy of the voter along with election process.Electronic voting reduces the human-involvement throughout the process from start to the end.Such system is not established yet in Pakistan.Hence,every election is disputed always.In this paper we proposed the framework of an e-voting system and simulation with the use of blockchain ledger technology.The proposed framework owns the capacity to deal with ballots in Pakistan.The novelty of the framework is that the e-voting system is linked to National Database and Registration Authority(NADRA)database which assures voter’s validation.The fundamental requirements were kept in consideration during the performance evaluation of the system.The results are processed and depicted specially with reference to the number of voters and voting stations,real time of vote casting,network bandwidth and controlling principles.The results support the decision makers and guide them in the foundation and customization of an e-voting system in Pakistan.

AudiTEE: Efficient, General-Purpose and Privacy-Preserving Audit for Distributed Ledgers

Privacy-preservation and effective auditing are two desirable but challenging requirements on distributed ledgers. To meet the requirements, this paper presents an auditing scheme, called as AudiTEE, which can audit a distributed ledger in a generic, efficient, and privacy-preserving manner. AudiTEE leverages Trusted Execution Environment (TEE) to generate confidential but auditable transactions and realize arbitrary, efficient and confidential audit on them. Unfortunately, TEE suffers from some inherent barriers and is itself not a complete solution for fast audit. To tackle these challenges, AudiTEE takes advantage of KAMT (K-anonymity Authentication Based on Merkle Tree) protocol for efficient management on account and user-defined anonymous transactions. Further, to achieve a complete and fast audit with unlinkability, TEE doesn’t process through all but only a comparatively small part of transactions according to a special ktag attached on each transaction to ensure that a user cannot hide transactions from auditor even when auditor is blind with who is involved in each transaction on the ledger. Apart from the above, AudiTEE allows flexible control on user behaviors. We implement a concrete instance of AudiTEE under a bank setting and demonstrate the scalability with all its core functionalities.

Simulation study on the security of consensus algorithms in DAG-based distributed ledger

Due to the advantages of high volume of transactions and low resource consumption,Directed Acyclic Graph(DAG)-based Distributed Ledger Technology(DLT)has been considered a possible next-generation alternative to blockchain.However,the security of the DAG-based system has yet to be comprehensively understood.Aiming at verifying and evaluating the security of DAG-based DLT,we develop a Multi-Agent based IOTA Simulation platform called MAIOTASim.In MAIOTASim,we model honest and malicious nodes and simulate the configurable network environment,including network topology and delay.The double-spending attack is a particular security issue related to DLT.We perform the security verification of the consensus algorithms under multiple double-spending attack strategies.Our simulations show that the consensus algorithms can resist the parasite chain attack and partially resist the splitting attack,but they are ineffective under the large weight attack.We take the cumulative weight difference of transactions as the evaluation criterion and analyze the effect of different consensus algorithms with parameters under each attack strategy.Besides,MAIOTASim enables users to perform largescale simulations with multiple nodes and tens of thousands of transactions more efficiently than state-of-the-art ones.

Hyperledger fabric platform for healthcare trust relations—Proof-of-Concept

In recent years,blockchain technologies have expanded from the finance field to other areas that rely on trustbased solutions.The healthcare industry represents one such area,as digital transformation disrupts relationships between patients,healthcare professionals,and healthcare institutes.Patients and healthcare institutes lack a proficient tool to verify the credentials of medical professionals in a digital environment.Furthermore,healthcare professionals lack a tool where they are in control over their credentials.The first contribution of this paper is a proposal of a solution that leverages the private permissioned Hyperledger Fabric blockchain and smart contracts to provide a source of transparent trust for relationships within the healthcare industry.Second,we pave the ground for GDPR compliance by storing only the hash values on the blockchain.Third,we solve the problem of patient authentication by utilizing cryptographic techniques.Finally,we prove the usability of the proposed solution by implementing a user interface and creating a live deployment.

A formal model for ledger management systems based on contracts and temporal logic

A key component of blockchain technology is the ledger,viz.,a database that,unlike standard databases,keeps in memory the complete history of past transactions as in a notarial archive for the benefit of any future test.In second-generation blockchains such as Ethereum,the ledger is coupled with smart contracts,which enable the automation of transactions associated with agreements between the parties of a financial or commercial nature.The coupling of smart contracts and ledgers provides the technological background for very innovative application areas,such as Decentralized Autonomous Organizations(DAOs),Initial Coin Offerings(ICOs),and Decentralized Finance(DeFi),which propelled blockchains beyond cryptocurrencies that were the only focus of first generation blockchains,such as Bitcoin.However,the currently used implementation of smart contracts as arbitrary programming constructs has made them susceptible to dangerous bugs that can be exploited maliciously and has moved their semantics away from that of legal contracts.We propose here to recompose the split and recover the reliability of databases by formalizing a notion of contract modeled as a finite-state automaton with well-defined computational characteristics derived from encoding in terms of allocations of resources to actors,as an alternative to the approach based on programming.To complete the work,we use temporal logic as the basis for an abstract query language that is effectively suited to the historical nature of the information kept in the ledger.

区块链分片技术研究综述

区块链技术以去中心化、防篡改等功能为特色,具有广泛的应用前景。然而,区块链系统难以支撑大规模海量的分布式数据管理和交易,所以区块链的性能和可扩展性问题成为重要的研究方向。目前,研究人员分别从修改链上的数据结构和共识算法,到添加链下操作技术,提出了一些解决方案,以提高区块链的性能和可扩展性。而其中,随着网络规模的增加,实现水平扩展性的最实用的方法就是分片技术。作为一种链上扩容方式,分片技术是一种将整个区块链网络划分成多个片段的方法,便于同时处理多个交易或合约。每个分片都可以独立运行,拥有自己的交易历史和状态,在不牺牲中心化程度的同时提高了区块链的性能和可扩展性。以往的大量区块链分片技术研究着重介绍了分片中的交易共识,而忽略了分片策略机制与分片架构。为此,首先对现有的分片区块链进行系统分析,将分片区块链的设计过程分为架构设置、节点选择、节点分配、交易分发、交易处理和分片重构等部分,并分析了分片区块链的设计过程的各部分的功能、属性;其次,对分片架构进行了分类和总结,重点研究了各种分片策略与机制,分析了它们的优缺点;之后,对主流的分片区块链系统做了比较,并分析了它们的可扩展性和可靠性,包括系统吞吐量、时延、通信开销、节点随机性、分片安全性和跨片智能合约等;最后,提出未来可能的研究方向。

基于区块链技术的数据溯源模型设计

文章设计并实现了一个基于区块链技术的数据溯源模型,详细介绍了模型的架构设计、关键技术选取及实现过程。结果表明,该区块链数据溯源模型不仅能提升数据的安全性、透明度,还能在实际应用中提高系统的操作效率与信任度,充分展示了区块链技术在跨行业数据管理中的广泛适用性与潜在优势。

基于区块链的校园智能停车能源交易平台的设计

提出一个基于区块链的智能校园停车场电动汽车能源交易平台。智能停车场是能够同时支持电动汽车停车和充电服务的智能场所,该系统架构由物理和网络基础设施层组成,区块链技术是促进参与者之间能源交易的有效途径。定义了参与者、资产、交易以及相互之间的智能链接,研究了两种场景,一个场景是电动汽车作为卖方和控制器作为买方之间的能源交易,第二个场景是电动汽车作为买方和控制器作为卖方之间的能源交易。这种平台既为参与者提供了利润,又平衡了大学校园高峰时期的能源负载需求。

联盟链型供应链金融系统的构建、机制和应用

供应链金融有利于缓解企业融资瓶颈,但还有许多理论和实践问题亟须解决。以联盟链为底层技术,将企业、银行和政府部门等参与主体连接在一起,构建联盟链型供应链金融系统,并深入讨论联盟链型供应链金融系统的选型依据、网络架构、运行机制和业务应用。研究表明:(1)相对于公有链和私有链而言,联盟链的部分去中心化、共识信任、不可篡改、智能合约和隐私性等优良特性,能够有效满足供应链金融的业务性、安全性和监管性等要求;(2)采用实用性拜占庭容错算法经过“选主、打包、建块和验证”实现一致共识后将数据上链存储于联盟链分布式总账本,是联盟链型供应链金融系统运行机制的关键;(3)通过采用联盟链型供应链金融系统,供应链上中小企业的融资绩效能够显著提高,即获取资金时间缩短、贷款利率降低和贷款规模扩大。研究结果可以为解决供应链上中小企业的融资难融资贵问题提供新路径和新方案,同时为银行和企业等进行联盟链型供应链金融系统的开发与应用提供现实指引。

云际分布记账模型、机理与关键技术展望

云际计算是支持公有云、私有云、边缘云和微云等异源异质云服务以自主对等方式纵横协作共赢的新型计算模式,可为独立云服务实体间行为交互、信任构建和贡献度量等提供防篡改、可追溯能力支持,进而最大限度削弱阻碍不同利益攸关者协作的不确定性因素.提升云际协作意愿和效率需要基于何种机理进行何种机制创新,是云际计算成长演化中需要进一步阐述的新问题.本文首先以基于“数字空间证据”构建或增强信任关系为设计原则,提出了基于区块链的云际分布记账软件定义模型,并系统阐述了分布记账支撑云际服务独立性、可审计性以及释放云际协作潜能的内在机理;其次,面向云际复杂交互行为,深化并固化了云际分布记账运行逻辑流程及关键环节的设计,避免其在错综复杂要素综合作用下呈现不确定冲突和矛盾;再次,针对数据要素流通及复杂异步交互场景,细化并优化了云际分布记账合约逻辑模型;最后,论述了以分布共识、智能合约等为代表的云际分布记账核心技术及相应指标的现状,并对关键技术的目标属性体系、前瞻性挑战等进行了展望.

医疗设备检定管理系统的设计与实现

目的针对传统医疗设备检定管理中效率低、共享难等问题,开发一套医疗设备检定管理系统。方法使用Adobe Dreamweaver CS6作为开发工具,phpStudy集成环境下Apache、MySQL作为服务器和数据库平台。从检定管理的全过程实际需求出发,系统实现权限分级、动态台账管理、现场检定过程管理和信息化查询与共享等功能模块。结果系统的应用测试结果表明,剩余待检设备统计耗时由(21.40±1.66)s缩短至(4.30±0.46)s,台账建立耗时由(61.40±6.87)s缩短至(15.80±0.72)s,且差异均有统计学意义(P<0.05);证书查询方面较系统应用前效率提高了16.21%,但差异无统计学意义(P=0.080)。结论该系统的应用显著推动了医疗设备检定管理的信息化与科学化,减少了人工操作,用户使用更加便捷,为医院的设备质量管理提供了有力的技术支持。

企业危险废物规范化环境管理评估与对策建议——以某省为例

为有效防控危险废物环境风险,应对企业实施危险废物规范化环境管理并评估,而如何评估分析和采取措施是提升危险废物管理水平的关键所在。基于危险废物规范化环境管理评估指标,评估某省企业危险废物规范化环境管理的现状,抽查结果表明企业规范化环境管理合格率高达95.1%。通过统计存在问题的企业数量及其占比,发现较多企业存在危险废物管理计划内容不全、台账记录和申报登记错报漏报、贮存设施环境管理不到位、危险废物识别标志不规范、污染防治责任制度不健全、经营管理台账记录和经营情况报告内容缺失、排污许可制度执行不到位等问题。同时,有针对性地提出提高危险废物申报材料质量、强化危险废物环境管理和鼓励第三方技术服务等对策及建议,以期解决危险废物规范化管理问题。

基于分布式智能合约的蜂群自组网安全组播通信及应用

随着无人集群技术的发展及其在竞争性环境中的部署应用,基于对称加密方法的自组织网络通信安全技术已不能满足分布式作战应用对组播通信安全、分布式行为审计和动态成员管理的安全要求。基于此,本文提出利用非对称数字签名进行会员身份管理,通过分布式块链处理进行组播通信安全审核,基于分布式智能合约实现蜂群自组网安全组播通信架构的无中心、防篡改、可追溯的通信安全策略,同时采用轻量化认证账本进行多任务链的分块存储,以此保障数据区块链的存储效率。本文深入研究了自组网安全组播通信的关键技术,并给出了这些技术的潜在应用方向,可供本领域系统架构设计和技术研究参考。

企业总账会计由核算型向管理型转变路径探索

在新环境下,企业总账会计由核算型向管理型转变是时代发展的必然趋势,对于管理型总账会计而言,关键任务在于对财务信息进行精准核算,为企业各项经济管理和战略决策提供有力的数据支撑,从而帮助企业实现经济效益最大化。所以文章从这一视角出发,对总账会计向管理型转变的重要性进行了分析,并就其具体要求和转变路径进行了探讨,希望能帮助企业更加有效地推动总账会计从核算型向管理型转变,以实现更大的经济和社会效益。

VBA编程在药企留样管理中的应用与效果

VBA编程技术在药企留样管理中具有良好的应用前景,其能有效提升留样管理的效率和准确性,为保证药品质量和患者安全提供了有力支持。采用VBA编程技术开发了一种留样管理系统,并以《外观观察记录》作为应用示例。通过对比使用VBA编程技术和传统方法管理留样电子台账的效率和数据分析能力,评估了VBA编程在留样管理中的效果。结果表明,使用VBA编程技术可有效提高管理留样电子台账的效率和数据分析能力。其优势不仅体现在操作上能简化流程、提高工作效率,还能实现自动化数据处理和生成报表,方便留样管理人员工作。

零知识证明下可审计追溯区块链隐私保护模型

为解决区块链网络中各节点共享账本导致敏感数据暴露,以及隐私数据加密导致无法审计追溯的问题,提出一种基于有向图和零知识证明的可审计追溯的区块链隐私保护模型。该模型基于Hyperledger Fabric开源框架进行扩展,有效继承Fabric的特性,通过对链上交易信息加密,利用Pedersen承诺和Schnorr类型的零知识证明生成平衡证明、追溯证明、资产证明和一致性证明,以提供快速的、可证明正确的隐私数据审计;利用有向图结构账本构建交易图,实现对区块链上交易信息的可追溯性,并对前向交易生成证明验证追溯的正确性。实验结果表明,所提出的模型以不到10%的吞吐量为代价在Fabric上实现了完整的审计和可追溯,其性能更优于现有的相关模型。