VacChain: A Blockchain-Based EMR System to Manage Child Vaccination Records

The digitalization of healthcare-related information service systems has become a trend across the world. However, several crucial services are still provided manually due to a lack of trust in digital solutions. One such service is keeping records of children’s vaccination, which still relies on a paper-based file system in most parts of the world. This approach causes serious data integrity problems. Recently, healthcare has become a potential application area of the blockchain, as it can preserve and protect highly sensitive private medical records while sharing these records in a decentralized manner without losing personal ownership. Therefore, we propose a new digital model to track a child’s vaccination records using blockchain. In particular, this proposed application helps improve the vaccination record-keeping process by ensuring the integrity of the preserved data in a more secure way. In an emerging pandemic situation, our approach can be extended to manage the overall vaccination process effectively.     

Blockchain-Assisted Secure Fine-Grained Searchable Encryption for a Cloud-Based Healthcare Cyber-Physical System

The concept of sharing of personal health data over cloud storage in a healthcare-cyber physical system has become popular in recent times as it improves access quality. The privacy of health data can only be preserved by keeping it in an encrypted form, but it affects usability and flexibility in terms of effective search. Attribute-based searchable encryption (ABSE) has proven its worth by providing fine-grained searching capabilities in the shared cloud storage. However, it is not practical to apply this scheme to the devices with limited resources and storage capacity because a typical ABSE involves serious computations. In a healthcare cloud-based cyber-physical system (CCPS), the data is often collected by resource-constraint devices; therefore, here also, we cannot directly apply ABSE schemes. In the proposed work, the inherent computational cost of the ABSE scheme is managed by executing the computationally intensive tasks of a typical ABSE scheme on the blockchain network. Thus, it makes the proposed scheme suitable for online storage and retrieval of personal health data in a typical CCPS. With the assistance of blockchain technology, the proposed scheme offers two main benefits. First, it is free from a trusted authority, which makes it genuinely decentralized and free from a single point of failure. Second, it is computationally efficient because the computational load is now distributed among the consensus nodes in the blockchain network. Specifically, the task of initializing the system, which is considered the most computationally intensive, and the task of partial search token generation, which is considered as the most frequent operation, is now the responsibility of the consensus nodes. This eliminates the need of the trusted authority and reduces the burden of data users, respectively. Further, in comparison to existing decentralized fine-grained searchable encryption schemes, the proposed scheme has achieved a significant reduction in storage and computational cost for the secret key associated with users. It has been verified both theoretically and practically in the performance analysis section.      

Decentralized semantic provision of personal health streams

Personalized healthcare is nowadays driven by the increasing volumes of patient data, observed and produced continuously thanks to medical devices, mobile sensors, patient-reported outcomes, among other data sources. This data is made available as streams, due to their dynamic nature, which represents an important challenge for processing, querying and interpreting the incoming information. In addition, the sensitive nature of healthcare data poses significant restrictions regarding privacy, which has led to the emergence of decentralized personal data management systems. Data semantics play a key role in order to enable both decentralization and integration of personal health data, as they introduce the capability to represent knowledge and information using ontologies and semantic vocabularies. In this paper we describe the SemPryv system, which provides the means to manage personal health data streams enriched with semantic information. SemPryv is designed as a decentralized system, so that users have the possibility of hosting their personal data at different sites, while keeping control of access rights. The semantization of data in SemPryv is implemented through different strategies, ranging from rule-based annotation to machine learning-based suggestions, fed from third-party specialized healthcare metadata providers. The system has been made available as Open Source, and is integrated as part of the Pryv.io platform used and commercialized in the healthcare and personal data management industry.     

基于DAG的分布式账本共识机制研究

自2008年比特币出现以来,研究学者相继提出了多种分布式账本技术,其中,区块链是当前分布式账本最主要的实现形式之一.但当前区块链中存在一个核心问题:可扩展性瓶颈.具体而言,区块链的吞吐量严重不足,且其交易确认也较为缓慢,这些因素极大地限制了它的实际应用.在此背景下,基于DAG(有向无环图)的分布式账本因其具有高并发特性,有望突破传统区块链中的性能瓶颈,从而受到了学术界和产业界越来越多的关注和研究.在基于DAG的分布式账本中,最为核心和关键的技术是其共识机制,为此,对该关键技术进行了系统深入的研究.首次从共识形态出发将现有基于DAG的分布式账本分为以下3类:基于主干链的DAG账本;基于平行链的DAG账本;基于朴素DAG的账本.在此基础上,对不同类型的共识机制本质原理及特性进行了深入阐述,并从不同层面对它们进行了详细的对比分析.最后,指出基于DAG的共识机制研究中存在的问题与挑战,并给出进一步的研究方向.     

区块链存储：技术与挑战

区块链具有不可被篡改和去中心化的特性,将其应用到存储系统中,有助于提高存储系统的数据安全性和系统可扩展性。区块链技术与存储技术的融合主要分为 3 方面：基于区块链构建的去中心化存储系统、基于区块链优化已有系统的存储性能和区块链系统自身的存储方法与优化。对这些工作进行了综述,讨论对比了当前典型的采用了区块链技术的存储系统,总结了区块链存储面临的主要挑战,并展望了区块链存储的发展方向。     

Privacy Preserving Biometric Authentication on the blockchain for smart healthcare

Privacy Preserving Biometric Authentication (PPBA) schemes are designed for anonymous authentication of patients to protect patient’s privacy in accessing healthcare services. Recently, blockchain technology in healthcare has emerged as a new research area to provide tamper-resistance and non-repudiation in e-health systems. One aspect of this research could lead to blockchain-based secure biometric identification for smart healthcare, which may face the paradox of anonymous biometric authentication on public blockchains. In this paper, we describe an efficient, fully anonymous and GDPR-compliant PPBA protocol built into the blockchain of any privacy coin such as Monero. The new protocol provides encrypted offline storage and processing in the encrypted domain. The infrastructure necessary for the online authentication is outsourced to the public blockchain that provides integrity of its data. In addition to auditing capabilities for misbehaving entities, the new system reduces the number of transactions necessary for authentication and enables revocation of biometric identities. We provide new PPBA schemes both for set difference/overlap and Euclidean distance metrics without using bilinear pairings, where the former leads to an efficient solution to the compatibility for organ transplant. We limit the generation of encrypted templates for public testing even if biometric/health data is of low min-entropy. Due to the anonymity of the cryptocurrency, we break the link between the stealth address of an authenticating user and its biometrics. We describe the user and identity privacy notions independent of the underlying privacy coin and guarantee the security of our proposal in the framework of those generic notions. Finally, we simulate the new proposal on Monero blockchain and analyze the transaction fees required for hill climbing attacks. The results show that our design leads to a natural hindrance against these attacks that could be successful even if the templates are stored as encrypted. To the best of our knowledge, this is the first efficient blockchain-based PPBA scheme that exhibits a punishment against hill climbing attacks through transaction fees.     

一种基于区块链的数据完整性验证解决方案

数据在物联网环境下采集、传递、存储过程中,如果缺少严密的安全防范措施,可能会出现假冒的、被篡改的或者过期的数据,这些缺乏完整性保护的物联网数据会对物联网应用造成极大的危害。数据的完整性是确保数据可信的必要条件。区块链的去中心化、分布式、持久性、不可篡改等属性,使得区块链目前成为在具有隐私保护应用需求的数据完整性验证的优选方法。文中提出了一种基于区块链的数据完整性验证的区块链结构和基于去中心化时间戳的数据完整性验证机制,设计了基于区块链的数据完整性验证的智能合约,在以太坊平台上模拟真实场景。实验结果表明,基于区块链的数据完整性验证技术方案,可以在去中心化的应用环境下,并在数据分散存储以保护数据隐私的前提下,确保数据的完整性。     

比特币区块链的数据压缩

区块链技术为数据存储提供了一种透明、不可更改、去中心化的方法.但随着数据量不断增加,比特币区块链系统需要大量的存储空间.分析了比特币区块的结构,针对比特币交易中的部分字段,提出相应的编码方案来减小比特币区块体积.实验表明,所提方案可使区块链体积减小18.13％.     

基于区块链的智能组件:一种分布式人工智能研究新范式

[目的]促进区块链与新一代人工智能技术的融合发展,利用人工智能的学习、推理和决策能力解决区块链面临的关键问题与挑战,已经成为区块链技术发展的重要突破口.[方法]致力于研究区块链与人工智能相结合的新范式,将目前相对中心化的人工智能算法嵌入到去中心化的区块链系统,使得二者共融、增强.[结果]提出了区块链赋能的智能组件概念与...     

Theoretical and practical applications of blockchain in healthcare information management

A primary objective of blockchain technology is to address information security and efficiency issues related to existing information sharing systems. For the sharing of health records, little is known about the application of blockchain in management information systems. There are strict regulations for sharing health information due to insecure systems and privacy concerns. To significantly and effectively improve medical diagnosis, it is beneficial to have efficient, reliable, and accurate accessibility to a patient's full medical history. Due to concerns with the security of health systems and privacy concerns, medical histories are not always accessible to healthcare providers. To help increase accessibility options, this research proposes a blockchain-based model that facilitates sharing medical records in a manner that is beneficial to both healthcare providers and patients. Social exchange theory provides the theoretical support for the conceptual model presented. Experimental findings based on 151 participants revealed that the blockchain technology can provide a secure information system and increase patient motivation to share medical records. To show the applicability of the proposed use of blockchain from a practical managerial perspective, we show feasibility by developing an Android software application.     

Proof of Activity Protocol for IoMT Data Security

The Internet of Medical Things (IoMT) is an online device that senses and transmits medical data from users to physicians within a time interval. In, recent years, IoMT has rapidly grown in the medical field to provide healthcare services without physical appearance. With the use of sensors, IoMT applications are used in healthcare management. In such applications, one of the most important factors is data security, given that its transmission over the network may cause obtrusion. For data security in IoMT systems, blockchain is used due to its numerous blocks for secure data storage. In this study, Blockchain-assisted secure data management framework (BSDMF) and Proof of Activity (PoA) protocol using malicious code detection algorithm is used in the proposed data security for the healthcare system. The main aim is to enhance the data security over the networks. The PoA protocol enhances high security of data from the literature review. By replacing the malicious node from the block, the PoA can provide high security for medical data in the blockchain. Comparison with existing systems shows that the proposed simulation with BSD-Malicious code detection algorithm achieves higher accuracy ratio, precision ratio, security, and efficiency and less response time for Blockchain-enabled healthcare systems.     

Decentralized data access control over consortium blockchains

Blockchain is an emerging data management technology that enables people in a collaborative network to establish trusted connections with the other participants. Recently consortium blockchains have raised interest in a broader blockchain technology discussion. Instead of a fully public, autonomous network, consortium blockchain supports a network where participants can be limited to a subset of users and data access strictly controlled. Access control policies should be defined by the respective data owner and applied throughout the network without requiring a centralized data administrator. As a result, decentralized data access control (DDAC) emerges as a fundamental challenge for such systems. However, we show from a trust model for consortium collaborative networks that current consortium blockchain systems provide limited support for DDAC. Further, the distributed, replicated nature of blockchain makes it even more challenging to control data access, especially read access, compared with traditional DBMSes. We investigate possible strategies to protect data from being read by unauthorized users in consortium blockchain systems using combinations of ledger partitioning and encryption strategies. A general framework is proposed to help inexperienced users determine appropriate strategies under different application scenarios. The framework was implemented on top of Hyperledger Fabric to evaluate feasibility. Experimental results along with a real-world case study contrasted the performance of different strategies under various conditions and the practicality of the proposed framework.     

区块链在数据安全领域的研究进展

大数据时代,数据已成为驱动社会发展的重要的资产.但是数据在其全生命周期均面临不同种类、不同层次的安全威胁,极大降低了用户进行数据共享的意愿.区块链具有去中心化、去信任化和防篡改的安全特性,为降低信息系统单点化的风险提供了重要的解决思路,能够应用于数据安全领域.该文从数据安全的核心特性入手,介绍区块链在增强数据机密性、数...     

基于区块链的轻量级匿名评审协议

同行评审的重要价值一直被学术界广泛认可,然而其过程的不透明广受诟病。近年来,区块链技术的快速发展正在迅速推动以太坊等开放式智能合约平台的成熟,为开发去中心化的评审系统奠定了坚实基础。然而,目前去中心化的评审协议面临两个有挑战性的问题。首先,由于区块链记录的信息是透明公开的,若评审方的身份在评审结果产生前被公开,会导致匿名性难以保障,不利于维护评审过程的公平性。其次,由于智能合约中函数的每一次调用都要花费一定量链上资源,执行包含n位评审方的协议需花费O（n）链上资源,导致可扩展性难以保障,协议难以应用到实际场景。本文提出一种基于区块链的轻量级匿名审稿协议（Blockchain-based Lightweight Anonymous Review, BLAR）,旨在解决去中心化评审协议的匿名性和可扩展性两个关键问题。BLAR协议不需要在评审结果展示前在区块链上存储任意可能导致指派信息泄露的信息,包括但不限于被选中评审方的账户地址或其哈希值,从而使攻击者无法确定性地找出对应某投稿的评审方。同时, BLAR协议不依赖区块链进行存储与计算,而是仅利用区块链进行验证和可信性保证,从而在最小程度造成...     

CoC: A Unified Distributed Ledger Based Supply Chain Management System

Modern supply chain is a complex system and plays an important role for different sectors under the globalization economic integration background. Supply chain management system is proposed to handle the increasing complexity and improve the efficiency of flows of goods. It is also useful to prevent potential frauds and guarantee trade compliance. Currently, most companies maintain their own IT systems for supply chain management. However, it is hard for these isolated systems to work together and provide a global view of the status of the highly distributed supply chain system. Using emerging decentralized ledger/blockchain technology, which is a special type of distributed system in essence, to build supply chain management system is a promising direction to go. Decentralized ledger usually suffers from low performance and lack of capability to protect information stored on the ledger. To overcome these challenges, we propose CoC (supply chain on blockchain), a novel supply chain management system based on a hybrid decentralized ledger with a novel two-step block construction mechanism. We also design an efficient storage scheme and information protection method that satisfy requirements of supply chain management. These techniques can also be applied to other decentralized ledger based applications with requirements similar to supply chain management.     

区块链在水利行业政府网站防篡改中的应用研究

水利行业各级政府网站所发布的信息应该及时、准确、权威,信息一旦被篡改,将会严重影响国家安全,损坏水利政府部门公信力和形象,传统防篡改系统存在默认信任特定节点,底稿存储不可靠等问题。为更好地保障水利行业政府网站信息安全,降低入侵风险,通过研究区块链的分布式记账原理和可信去中心化特点,提出一种基于区块链和分布式存储的新型防篡改系统。利用区块链的去中心化的信任机制和分布式存储的安全性,新型防篡改系统能够消除单点薄弱环节,可靠存储底稿文件,不需信任特定节点。测试结果表明：与传统防篡改系统相比,新型防篡改系统能够更好地满足水利行业政府网站在防篡改领域的需求,保证水利行业政府网站发布的内容得到有效保护,保护水利行业政府网站免遭篡改的侵害。     

区块链数据库:一种可查询且防篡改的数据库

随着比特币、以太币等一系列加密货币的兴起,其底层的区块链技术受到越来越广泛的关注.区块链有防篡改、去中心化的特性.以太坊利用区块链技术来构建新一代去中心化的应用平台.BigchainDB将区块链技术与传统的分布式数据库相结合,利用基于联盟投票的共识机制改进传统Pow机制中的节点全复制问题,提高了系统的扩展性与吞吐率.但是现有的区块链系统存储的信息大都是固定格式的交易信息,虽然在每个交易里有数据字段,但是现有的区块链系统并不能经由链上对交易内的数据字段的具体细节进行直接查询.如果想要查询数据字段的具体细节,只能先根据交易的哈希值进行查询,得到该交易的完整信息,然后再检索该交易内的数据信息.数据可操作性低,不具备传统数据库的查询功能.首先提出一种区块链数据库系统框架,将区块链技术应用于分布式数据管理;其次提出一种基于哈希指针的不可篡改索引,根据该索引快速检索区块内数据,以此实现区块链的查询;最后,通过实验测试数据库的读写性能,实验结果表明,所提出的不可篡改索引在保证不可篡改的同时具有较好的读写性能.     

区块链技术发展现状与展望

区块链是随着比特币等数字加密货币的日益普及而逐渐兴起的一种全新的去中心化基础架构与分布式计算范式, 目前已经引起政府部门、 金融机构、 科技企业和资本市场的高度重视与广泛关注. 区块链技术具有去中心化、 时序数据、 集体维护、 可编程和安全可信等特点, 特别适合构建可编程的货币系统、 金融系统乃至宏观社会系统. 本文通过解构区块链的核心要素, 提出了区块链系统的基础架构模型, 详细阐述了区块链及与之相关的比特币的基本原理、 技术、 方法与应用现状, 讨论了智能合约的理念、 应用和意义, 介绍了基于区块链的平行社会发展趋势, 致力于为未来相关研究提供有益的指导与借鉴.     

基于区块链技术的高校学生心理健康管理系统设计

区块链技术减轻了对中心设备的依赖,实现信息验证的完整性和所有权,其独特的分散和透明特性,可有效地解决信息管理过程中存在的记录不完整及难以获取自身心里健康信息等问题。高效的心理健康管理系统需要互操作性,这允许软件应用程序和技术平台安全、无缝的通信。本文采用区块链技术以安全且伪匿名的方式访问纵向、完整且可篡改的心理记录信息——这些记录存储在分散的系统中,实现异构系统间的信息交互,解决了心理健康管理过程中数据安全交互的问题。     

Integrating TTF and IDT to evaluate user intention of big data analytics in mobile cloud healthcare system

ABSTRACT

With the rapid development of mobile technology and cloud computing, observers have recognised the vast potential for mobile cloud healthcare systems in individualised preventive healthcare. Using a mobile cloud healthcare system and big data analysis, this study aids young users in preventive healthcare against diabetes. It also integrates the Task-Technology Fit (TTF) and Innovation Diffusion Theory (IDT) models to evaluate user intentions to use the system, and tests this model using data collected from 423 young people. Results show that task-technology fit is significantly affected by task characteristics and technology characteristics, and also user intention of using the mobile cloud healthcare system is affected by task-technology fit, complexity, and relative benefits. However, observability has no significant effect on user intentions of using the mobile cloud healthcare system. These findings provide some interesting theoretical insights into the usage of the mobile cloud healthcare system. The direct effects of TTF and IDT on young users′ intention of using the mobile cloud healthcare system are shown. This study thus makes an important contribution by highlighting the role that TTF and IDT may have in affecting use of the mobile cloud healthcare system.