Consensus protocols are used for the distributed management of large databases in an environment without trust among participants. The choice of a specific protocol depends on the purpose and characteristics of the system itself. The subjects of the paper are consensus protocols in permissioned blockchains. The objective of this paper is to identify functional advantages and disadvantages of observed protocol. The analysis covers a total of six consensus protocols for permissioned blockchains. The following characteristics were compared: security, trust among participants, throughput and scalability. The results show that no protocol shows absolute dominance in all aspects of the comparison. Paxos and Raft are intended for systems in which there is no suspicion of unreliable users, but only the problem of a temporary shutdown. Practical Byzantine Fault Tolerance is intended for systems with a small number of nodes. Federated Byzantine Fault Tolerance shows better scalability and is more suitable for large systems, but can withstand a smaller number of malicious nodes. Proof-of-authority can withstand the largest number of malicious nodes without interfering with the functioning of the system. When choosing a consensus protocol for a blockchain application, one should take into account priority characteristics.
In recent years we have witnessed a dramatic increase in the applications of blockchain and smart contracts in a variety of contexts, including supply-chain, decentralized finance, and international money transfers. However, a critical stumbling block to their further adoption is smart contract security (or more precisely, the lack thereof). Smart contracts, once deployed on a blockchain, are immutable. Hence, unlike traditional software systems, smart contracts are particularly vulnerable to latent security issues. It is therefore imperative that security analysis tools be developed that help improve smart contract security if they are to have continued adoption and impact. A particularly widespread class of security vulnerabilities that afflicts Ethereum smart contracts is the gas-based denial of service (DoS). Briefly, these vulnerabilities generally present in contracts containing unbounded loops. \n \nTo address the described problem, we present Gas Gauge, a tool aimed at detecting gas-based DoS vulnerabilities in Ethereum smart contracts. Gas Gauge consists of three major components: the Detection Phase, Identification Phase, and Correction Phase. First, we describe a highly accurate static analysis approach that finds all the loops in a smart contract (the Detection Phase). Then, a set of inputs that causes the contract to run out of gas is generated using a fuzzing approach. The last component uses static analysis and run-time verification to predict the maximum loop bounds consistent with allowable gas usage automatically. This component uses a binary search approach and an independent parallel processing design to speed up the process. Each part of the tool can be used separately for different purposes or all together to detect, identify and help repair the contracts vulnerable to out-of-gas behaviors. \n \nGas Gauge was tested on 2,000 real-world solidity smart contracts. The results were compared to seven state-of-the-art tools, and it was empirically demonstrated that Gas Gauge is highly effective and useful.
In the current epoch of smart homes and cities, personal data such as patients' names, diseases and addresses are often violated. This is frequently associated with the safety of the electronic health records (EHRs) of patients. EHRs have numerous benefits worldwide, but at present, EHR information is subject to considerable security and privacy issues. This paper proposes a way to provide a secure solution to these issues. Previous sophisticated techniques dealing with the protection of EHRs usually make data inaccessible to patients. These techniques struggle to balance data confidentiality, patient demand and constant interaction with provider data. Blockchain technology solves the above problems since it distributes information in a transactional and decentralized manner. The usage of blockchain technology could help the health sector to balance the accessibility and privacy of EHRs. This paper proposes a blockchain security framework (BSF) to effectively and securely store and keep EHRs. It presents a safe and proficient means of acquiring medical information for doctors, patients and insurance agents while protecting the patient's data. This work aims to examine how our proposed framework meets the security needs of doctors, patients and third parties and how the structure addresses safety and confidentiality concerns in the healthcare sector. Simulation outcomes show that this framework efficiently protects EHR data.
Abstract The persevering pursuit of security has proved historically limiting the implementation of significant design improvements for Electronic Health Records (EHR). Such a vital requirement for these kinds of technical development is revamped now. This is because the patients are motivated by personalization and data science to participate in the health information sharing. The implementation of cloud computing has already shown substantial benefits for both clinical organizations and patients in managing electronic health records. The prime security issue of cloud-based electronic health records is that the patient is physically unable to own a medical record whereas a clinical organization can maintain one for them. The latter may collude with centralized cloud servers. So, there is a vulnerability of such records being tampered with in order to hide the medical malpractices. So, maintaining data integrity and data privacy becomes a significant challenge when deploying cloud computing. Therefore, in this paper, a consortium blockchain-based cloud-stored electronic health record is proposed which provides data integrity, data privacy, storage scalability, and fine-grained access control. Each process in outsourcing electronic health records to the cloud is incorporated as a transaction in a consortium ethereum blockchain through smart contracts. Through smart contracts, an attribute-based contract key is generated for the users that can decrypt the encrypted data stored in the cloud. The attribute-based contract key allows only users who are authorized to access the information ensuring data privacy and fine-grained access control. Moreover, the proposed scheme is proved to provide tamper-proof although the medical records are controlled by a group of clinical organizations.
In recent years, we have witnessed the evolutionary development of a new breed of distributed systems. Systems of this type share a number of characteristics – highly decentralized, of Internet-grade scalability, and autonomous within their administrative domains. Most importantly, they are expected to operate collaboratively across both known and unknown domains. Prime examples include peer-to-peer applications and open web services. Typically, authorization in distributed systems is identity-based, e.g. access control lists. However, approaches based on predefined identities are unsuitable for the new breed of distributed systems because of the need to deal with unknown users, i.e. strangers, and the need to manage a potentially large number of users and/or resources. Furthermore, effective administration and management of authorization in such systems requires: (1) natural mapping of organizational policies into security policies; (2) managing collaboration of independently administered domains/organizations; (3) decentralization of security policies and policy enforcement. This thesis describes Fidelis, a trust management framework designed to address the authorization needs for the next-generation distributed systems. A trust management system is a term coined to refer to a unified framework for the specification of security policies, the representation of credentials, and the evaluation and enforcement of policy compliances. Based on the concept of trust conveyance and a generic abstraction for trusted information as trust statements, Fidelis provides a generic platform for building secure, trust-aware distributed applications. At the heart of the Fidelis framework is a language for the specification of security policies, the Fidelis Policy Language (FPL), and the inference model for evaluating policies expressed in FPL. With the policy language and its inference model, Fidelis is able to model recommendation-style policies and policies with arbitrarily complex chains of trust propagation. Web services have rapidly been gaining significance both in industry and research as a ubiquitous, next-generation middleware platform. The second half of the thesis describes the design and implementation of the Fidelis framework for the standard web service platform. The goal of this work is twofold: first, to demonstrate the practical feasibility of Fidelis, and second, to investigate the use of a policy-driven trust management framework for Internet-scale open systems. An important requirement in such systems is trust negotiation that allows unfamiliar principals to establish mutual trust and interact with confidence. Addressing this requirement, a trust negotiation framework built on top of Fidelis is developed. This thesis examines the application of Fidelis in three distinctive domains: implementing generic role-based access control, trust management in the World Wide Web, and an electronic marketplace comprising unfamiliar and untrusted but collaborative organizations.
Interoperation for data sharing between permissioned blockchain networks relies on networks' abilities to independently authenticate requests and validate proofs accompanying the data; these typically contain digital signatures. This requires counterparty networks to know the identities and certification chains of each other's members, establishing a common trust basis rooted in identity. But permissioned networks are ad hoc consortia of existing organizations, whose network affiliations may not be well-known or well-established even though their individual identities are. In this paper, we describe an architecture and set of protocols for distributed identity management across permissioned blockchain networks to establish a trust basis for data sharing. Networks wishing to interoperate can associate with one or more distributed identity registries that maintain credentials on shared ledgers managed by groups of reputed identity providers. A network's participants possess self-sovereign decentralized identities (DIDs) on these registries and can obtain privacy-preserving verifiable membership credentials. During interoperation, networks can securely and dynamically discover each others' latest membership lists and members' credentials. We implement a solution based on Hyperledger Indy and Aries, and demonstrate its viability and usefulness by linking a trade finance network with a trade logistics network, both built on Hyperledger Fabric. We also analyze the extensibility, security, and trustworthiness of our system.
Muneeb Ejaz, Tanesh Kumar, Ivana Kovacevic, Mika Ylianttila · 5 authors
The rapid evolution of technology allows the healthcare sector to adopt intelligent, context-aware, secure, and ubiquitous healthcare services. Together with the global trend of an aging population, it has become highly important to propose value-creating, yet cost-efficient digital solutions for healthcare systems. These solutions should provide effective means of healthcare services in both the hospital and home care scenarios. In this paper, we focused on the latter case, where the goal was to provide easy-to-use, reliable, and secure remote monitoring and aid for elderly persons at their home. We proposed a framework to integrate the capabilities of edge computing and blockchain technology to address some of the key requirements of smart remote healthcare systems, such as long operating times, low cost, resilience to network problems, security, and trust in highly dynamic network conditions. In order to assess the feasibility of our approach, we evaluated the performance of our framework in terms of latency, power consumption, network utilization, and computational load, compared to a scenario where no blockchain was used.
Academic degrees are subject to corruptions, system flaws, forgeries, and imitations. In this paper we propose to develop a blockchain smart contract-based application using Ethereum Platform, to store, distribute and verify academic certificates. It constitutes a trusted, decentralized certificate’s management system that can offer a unified viewpoint for students, academic institutions, as well as for other potential stakeholders such as employers. The article describes the implementation of three main parts of our proposed solution that includes: verification application, university interface and accreditor interface. This application avoids administrative barriers, makes the process of deployment, verification, and validation of certificates faster, efficient, and more secure. Additionally, it offers confidentiality of the data by using AES encryption algorithm before creating transactions and allows bulk submission of multiple academic certificates.
Cho Nwe Zin Latt, Sandi Rahmadika, Kyung-Hyune Rhee
The Myanmar rice cycle’s existing system is still relying on a third party to manage every rice data information from several organizations. It is inconvenient to supervise simultaneously due to the unreliability of information provided by organizations. Thus, the rice cycle’s original data is challenging to be utterly trusted since irresponsible parties can manipulate the current state of information. Moreover, the applied system does not preserve a proper incentive for the involved parties. In this paper, we leverage the Ethereum blockchain to be adopted to tackle the aforementioned issues. The main objective is to build trust between parties in the Myanmar rice cycle system. Our proposed scheme allows customers to check and trace information about the rice cycle information without worrying about the integrity of the data. Furthermore, the authorized parties are also rewarded by the government through Ethereum smart contract features. Eventually, our scheme achieves traceability in the rice chain system and leads to the complete digitization and automation of the rice cycle information.
Blockchain’s versatility is primarily due to its immutable and almost indestructible nature. These attributes have caught the attention of researchers and developers interested in applications and environments where the need for the integrity of identity and content are as paramount as the safe delivery and record of transactions. Self-sovereign digital identity in particular is often cited as a human right that nation states need to embrace with as much conviction as education and lifelong learning are considered to be a public good. Although the blockchain has long been identified as an opportunity for driving much-needed change in the core processes of the education sector, use cases to date have been limited in scope and execution, with blockchain advocates and education policy makers seemingly disconnected on fundamental issues such as governance, self-sovereignty, interoperability, choice of blockchain platforms and overall trust in standards and the integrity of the infrastructure. This article is primarily interested in the affordances of the technology as a public good for the education sector. It levers on the lead author’s perspective as a mediator between the blockchain and education sectors in Europe on high-profile blockchain in education projects to provide a snapshot of the challenges and workable solutions in the blockchain-enabled, European digital credentials sector.
Robert Karaszewski, Paweł Modrzyński, Joanna Modrzyńska
Blockchain technology is currently one of the trends considered to have a tremendous future ahead. It ensures data security, data sharing protection and automation development—elements that are of colossal importance in the era of cloud solutions, big data and Internet of Things (IoT) reality. Additionally, blockchain technology allows one to create new programmable ecosystems on an unprecedented scale. The implementation of blockchain technology leads not only to improving the flow of documents and data storage, as is the case with the creation of shared service centers (SSCs), but—as this paper shows—allows one to reduce the carbon footprint when servicing SSCs at a considerably higher organizational level at the same time. The example of an SSC in Elbląg, Poland, proves that cloud solutions enabling electronic documents flow and data storage combined with blockchain technology are tools essential for further SSCs development. Furthermore, such tools allow us not only to obtain economic effects (i.e., cost reduction), but also to achieve positive ecological effects (i.e., carbon footprint reduction).
Tzung‐Her Chen, Ting-Le Zhu, Fuh-Gwo Jeng, Chien-Lung Wang
Although encryption and signatures have been two fundamental technologies for cryptosystems, they still receive considerable attention in academia due to the focus on reducing computational costs and communication overhead. In the past decade, applying certificateless signcryption schemes to solve the higher cost of maintaining the certificate chain issued by a certificate authority (CA) has been studied. With the recent increase in the interest in blockchains, signcryption is being revisited as a new possibility. The concepts of a blockchain as a CA and a transaction as a certificate proposed in this paper aim to use a blockchain without CAs or a trusted third party (TTP). The proposed provably secure signcryption scheme implements a designated recipient beforehand such that a sender can cryptographically facilitate the interoperation on the blockchain information with the designated recipient. Thus, the proposed scheme benefits from the following advantages: (1) it removes the high maintenance cost from involving CAs or a TTP, (2) it seamlessly integrates with blockchains, and (3) it provides confidential transactions. This paper also presents the theoretical security analysis and assesses the performance via the simulation results. Upon evaluating the operational cost in real currency based on Ethereum, the experimental results demonstrate that the proposed scheme only requires a small cost as a fee.
With the rapid development of blockchain technology, different types of blockchains are adopted and interoperability across blockchains has received widespread attention. There have been many cross-chain solutions proposed in recent years, including notary scheme, sidechain, and relay chain. However, most of the existing platforms do not take confidentiality into account, although privacy has become an important concern for blockchain. In this paper, we present TrustCross, a privacy- preserving cross-chain platform to enable confidential interoperability across blockchains. The key insight behind TrustCross is to encrypt cross-chain communication data on the relay chain with the assistance of trusted execution environment and employ fine-grained access control to protect user privacy. Our experimental results show that TrustCross achieves reasonable latency and high scalability on the contract calls across heterogeneous blockchains.
With the rising popularity of the Internet and the development of big data technology, an increasing number of organizations are opting to cooperate across domains to maximize their benefits. Most organizations use public key infrastructure to ensure security in accessing their data and applications. However, with the continuous development of identity-based encryption (IBE) technology, small- and medium-sized enterprises are increasingly using IBE to deploy internal authentication systems. To solve the problems that arise when crossing heterogeneous authentication domains and to guarantee the security of the certification process, we propose using blockchain technology to establish a reliable cross-domain authentication scheme. Using the distributed and tamper-resistant characteristics of the blockchain, we design a cross-domain authentication model based on blockchain to guarantee the security of the heterogeneous authentication process and present a cross-domain authentication protocol based on blockchain. This model does not change the internal trust structure of each authentication domain and is highly scalable. Furthermore, on the premise of ensuring security, the process of verifying the signature of the root certificate in the traditional cross-domain authentication protocol is improved to verify the hash value of the root certificate, thereby improving the authentication efficiency. The developed prototype exhibits generality and simplicity compared to previous methods.
In the process of sharing data, the costless replication of electric energy data leads to the problem of uncontrolled data and the difficulty of third-party access verification. This paper proposes a controlled sharing mechanism of data based on the consortium blockchain. The data flow range is controlled by the data isolation mechanism between channels provided by the consortium blockchain by constructing a data storage consortium chain to achieve trusted data storage, combining attribute-based encryption to complete data access control and meet the demands for granular data accessibility control and secure sharing; the data flow transfer ledger is built to record the original data life cycle management and effectively record the data transfer process of each data controller. Taking the application scenario of electric energy data sharing as an example, the scheme is designed and simulated on the Linux system and Hyperledger Fabric. Experimental results have verified that the mechanism can effectively control the scope of access to electrical energy data and realize the control of the data by the data owner.
Jinnan Zhang, Changqi Lu, Gang Cheng, Teng Guo · 8 authors
Edge computing is a product of the evolution of IoT and the development of cloud computing technology, providing computing, storage, network, and other infrastructure close to users. Compared with the centralized deployment model of traditional cloud computing, edge computing solves the problems of extended communication time and high convergence traffic, providing better support for low latency and high bandwidth services. With the increasing amount of data generated by users and devices in IoT, security and privacy issues in the edge computing environment have become concerns. Blockchain, a security technology developed rapidly in recent years, has been adopted by many industries, such as finance and insurance. With the edge computing capability, deploying blockchain platforms/applications on edge computing platforms can provide security services for network edge environments. Although there are already solutions for integrating edge computing with blockchain in many IoT application scenarios, they slightly lack scalability, portability, and heterogeneous data processing. In this paper, we propose a trusted edge platform to integrate the edge computing framework and blockchain network for building an edge security environment. The proposed platform aims to preserve the data privacy of the edge computing client. The design based on the microservice architecture makes the platform lighter. To improve the portability of the platform, we introduce the Edgex Foundry framework and design an edge application module on the platform to improve the business capability of Edgex. Simultaneously, we designed a series of well-defined security authentication microservices. These microservices use the Hyperledger Fabric blockchain network to build a reliable security mechanism in the edge environment. Finally, we build an edge computing network using different hardware devices and deploy the trusted edge platform on multiple network nodes. The usability of the proposed platform is demonstrated by testing the round-trip time (RTT) of several important workflows. The experimental results demonstrate that the platform can meet the availability requirements in real-world usage scenarios.
Abstract Remote patient monitoring and data management have gained much popularity in recent years because of their enhanced access to low‐cost healthcare services. A cloud‐based healthcare system provides numerous solutions for collecting patient data and offers on‐demand well‐managed reports to patients and healthcare providers. However, it equally suffers from single‐point failure, security, privacy, and non‐transparency issues with the data, impacting the continuity of the system. To resolve such concerns, this article proposes an artificial intelligence (AI)‐enabled decentralized healthcare framework that accesses and authenticates Internet of Things (IoT) devices and create trust and transparency in patient healthcare records (PHR). The mechanism is based on the AI‐enabled smart contracts and the conceptualization of the public blockchain network. Alongside this, the framework identifies the malicious IoT nodes in the system. The experimental analyses are performed on the real‐time test environment, and significant improvements are suggested in terms of device energy consumption, data request time, throughput, average latency, and transaction fee.
Security and privacy of patients’ data is a major concern in the healthcare industry. In this paper, we propose a system that activates robust security and privacy of patients’ medical records as well as enables interoperability and data exchange between the different healthcare providers. The work proposes the shift from patient’s electronic health records being managed and controlled by the healthcare industry to a patient-centric application where patients are in control of their data. The aim of this research is to build an Electronic Healthcare Record (EHR) system that is layered on the Ethereum blockchain platform and smart contract in order to eliminate the need for third-party systems. With this system, the healthcare provider can search for patient’s data and request the patients’ consent to access it. Patients manage their data which enables an expedited data exchange across EHR systems. Each patient’s data are stored on the peer-to-peer node ledger. The proposed patient-centric EHR platform is cross-platform compliant, as it can be accessed via personal computers and mobile devices and facilitates interoperability across healthcare providers as patients’ medical records are gathered from different healthcare providers and stored in a unified format. The proposed framework is tested on a private Ethereum network using Ganache. The results show the effectiveness of the system with respect to security, privacy, performance and interoperability.
Rafael Belchior, André Vasconcelos, Miguel Correia, Thomas Hardjono
The emergence of blockchain interoperability is reducing the risk of investing in blockchain by avoiding vendor lock-in, leveraging interoperation, and providing migration capabilities. However, to fully unlock the internet of blockchains, it is necessary to provide enterprise interoperability mechanisms that allow service providers to comply with different regulations, e.g., data privacy regulations. Each blockchain can be reached via a gateway, allowing to interconnect value, to provide different services, and to enable self-sovereignty. To realize this vision, we propose Hermes, a fault-tolerant middleware that connects blockchain networks and is based on the Open Digital Asset Protocol (ODAP). Hermes is crash fault-tolerant by allying a new protocol, ODAP-2PC, with a log storage API that can leverage blockchain to secure logs, providing them transparency, auditability, availability, and non-repudiation. We introduce a use case benefiting from Hermes, digital cross-jurisdiction promissory notes. We show that cross-chain transactions can be achieved securely with Hermes, given that gateways are complying with legal frameworks.
Zero-knowledge succinct non-interactive argument of knowledge (zkSNARK) allows a party, known as the prover, to convince another party, known as the verifier, that he knows a private value $v$, without revealing it, such that $F(u,v)=y$ for some function $F$ and public values $u$ and $y$. There are various versions of zk-SNARK, among them, Quadratic Arithmetic Program (QAP)-based zk-SNARK has been widely used in practice, specially in Blockchain technology. This is attributed to two desirable features; its fixed-size proof and the very light computation load of the verifier. However, the computation load of the prover in QAP-based zkSNARKs, is very heavy, even-though it is designed to be very efficient. This load can be beyond the prover's computation power to handle, and has to be offloaded to some external servers. In the existing offloading solutions, either (i) the load of computation, offloaded to each sever, is a fraction of the prover's primary computation (e.g., DZIK), however the servers need to be trusted, (ii) the servers are not required to be trusted, but the computation complexity imposed to each one is the same as the prover's primary computation (e.g., Trinocchio). In this paper, we present a scheme, which has the benefits of both solutions. In particular, we propose a secure multi-party proof generation algorithm where the prover can delegate its task to $N $ servers, where (i) even if a group of $T \in \mathbb{N}$ servers, $T\le N$, collude, they cannot gain any information about the secret value $v$, (ii) the computation complexity of each server is less than $1/(N-T)$ of the prover's primary computation. The design is such that we don't lose the efficiency of the prover's algorithm in the process of delegating the tasks to external servers.
It is the most important and challenging problem to share the data safely in cloud computing. Some so-called trusted third parties may also infringe users’ data privacy. It is an urgent problem for data owners to share data safely with the designated users rather than the third party or other users. Traditional encryption schemes utilize different keys to produce multiple encrypted copies of the same data for users. It is no longer applicable for cloud data sharing security. Attribute-based encryption can solve above problems, but it needs to rely on trusted third parties to protect the users’ privacy. In this article, in order to address the above problems, we propose a blockchain-based ciphertext-policy attribute-based encryption scheme for cloud data secure sharing without relying on any trusted third parties. Blockchain-based ciphertext-policy attribute-based encryption scheme can protect the rights and security of data owner. Compared with existing cloud security schemes, the proposed scheme has more advantages in terms of the six aspects: (1) data owners have the authority to decide who can decrypt the data; (2) the operations of users are retained permanently, and all records are tamper-proof; (3) our proposed scheme has the characteristic of “one-to-many” encryption, and data is encrypted only once; (4) our scheme does not rely on any trusted third party; (5) in terms of the discrete logarithm problem and decisional q parallel-bilinear Diffie–Hellman exponent problem, we prove that our proposed scheme is secure; and (6) experiment shows that our proposed scheme is more efficient than the comparative scheme.
The healthcare industry deals with highly sensitive data which must be managed in a secure way. Electronic Health Records (EHRs) hold various kinds of personal and sensitive data which contain names, addresses, social security numbers, insurance numbers, and medical history. Such personal data is valuable to the patients, healthcare service providers, medical insurance companies, and research institutions. However, the public release of this highly sensitive personal data poses serious privacy and security threats to patients and healthcare service providers. Hence, we foresee the requirement of new technologies to address the privacy and security challenges for personal data in healthcare applications. Blockchain is one of the promising solutions, aimed to provide transparency, security, and privacy using consensus-driven decentralised data management on top of peer-to-peer distributed computing systems. Therefore, to solve the mentioned problems in healthcare applications, in this paper, we investigate the use of private blockchain technologies to assess their feasibility for healthcare applications. We create testing scenarios using HyperLedger Fabric to explore different criteria and use-cases for healthcare applications. Additionally, we thoroughly evaluate the representative test case scenarios to assess the blockchain-enabled security criteria in terms of data confidentiality, privacy and access control. The experimental evaluation reveals the promising benefits of private blockchain technologies in terms of security, regulation compliance, compatibility, flexibility, and scalability.
Technology grows up, day to day to facilitate human beings’ lifestyle, in order to protect them and their properties. Cloud computing is a platform that one hardware is shared by different clients in the virtual ways and works as standalone physical hardware, is accessed everywhere at any time through the internet. Security is an essential and a vital point to all customers is belonged in the same physical component. This survey paper discusses about cloud computing challenges, types of attacks, and currently solutions in the details. Furthermore, cloud security of models as application, network, and deployment and also services. Cloud security based on a distributed ledger helps the clients to operate within transparency manners and is decentralized to enhance cloud computing information security principals, cloud security requirements, cloud security control, and security design of cloud computing