Blockchain Papers

Chunpeng Ge, Zhe Liu, Liming Fang

No abstract is available for this record.

Mohamed Yaseen Jabarulla, Heung-No Lee

In recent years, many researchers have focused on developing a feasible solution for storing and exchanging medical images in the field of health care. Current practices are deployed on cloud-based centralized data centers, which increase maintenance costs, require massive storage space, and raise privacy concerns about sharing information over a network. Therefore, it is important to design a framework to enable sharing and storing of big medical data efficiently within a trustless environment. In the present paper, we propose a novel proof-of-concept design for a distributed patient-centric image management (PCIM) system that is aimed to ensure safety and control of patient private data without using a centralized infrastructure. In this system, we employed an emerging Ethereum blockchain and a distributed file system technology called Inter-Planetary File System (IPFS). Then, we implemented an Ethereum smart contract called the patient-centric access control protocol to enable a distributed and trustworthy access control policy. IPFS provides the means for decentralized storage of medical images with global accessibility. We describe how the PCIM system architecture facilitates the distributed and secured patient-centric data access across multiple entities such as hospitals, patients, and image requestors. Finally, we deployed a smart contract prototype on an Ethereum testnet blockchain and evaluated the proposed framework within the Windows environment. The evaluation results demonstrated that the proposed scheme is efficient and feasible.

Madhumitha Harishankar, Dimitrios-Georgios Akestoridis, Sriram V. Iyer, Áron Lászka · 6 authors

Decentralized marketplace applications demand fast, cheap and easy-to-use cryptocurrency payment mechanisms to facilitate high transaction volumes. The standard solution for off-chain payments, state channels, are optimized for frequent transactions between two entities and impose prohibitive liquidity and capital requirements on payment senders for marketplace transactions. We propose PayPlace, a scalable off-chain protocol for payments between consumers and sellers. Using PayPlace, consumers establish a virtual unidirectional payment channel with an intermediary operator to pay for their transactions. Unlike state channels, however, the PayPlace operator can reference the custodial funds accrued off-chain in these channels to in-turn make tamper-proof off-chain payments to merchants, without locking up corresponding capital in channels with merchants. Our design ensures that new payments made to merchants are guaranteed to be safe once notarized and provably mitigates well-known drawbacks in previous constructions like the data availability attack and ensures that neither consumers nor merchants need to be online to ensure continued safety of their notarized funds. We show that the on-chain monetary and computational costs for PayPlace is O(1) in the number of payment transactions processed, and is near-constant in other parameters in most scenarios. PayPlace can hence scale the payment throughput for large-scale marketplaces at no marginal cost and is orders of magnitude cheaper than the state-of-art solution for non-pairwise off-chain payments, Zero Knowledge Rollups.

Gwan‐Hwan Hwang, Pei-Chun Tien, Yi-Hsiang Tang

In this paper we propose a blockchain-based automatic indemnification mechanism. Clients and service providers (SPs) exchange signed messages according to a predefined protocol that enables clients to utilize service-provider services with simultaneous cryptographic proof of service. When a client has discovered an SP to have violated a service level agreement based on cryptographic proof, then they can obtain cryptocurrency as a compensation by raising objections to a smart contract on a public blockchain. When an objection has been judged successful by programs located in the smart contract, a portion of the deposit (cryptocurrency in the smart contract) will be transferred to the account of the objection-raiser. In this way, the need to establish and run a customer service center with employees for processing such claims and refunds is obviated. Moreover, the traditional third-party trust is no longer needed. Focusing on services for cloud-storage service, we propose protocols and implementation of an indemnification system in the Ethereum. The feasibility of the proposed application has been demonstrated through pilot implementation and testing.

Donghyeok Lee, Namje Park

No abstract is available for this record.

Martin Smits, Joris Hulstijn

In the current discussions around Blockchain and distributed ledger technologies, we find a lack of theory to conceptualize and understand application scenarios. In this paper we propose to conceptualize distributed ledger technologies as trust mechanisms. Whereas previously one had to rely on a trusted third party (e.g. notary), now one must trust a complex software system – the Blockchain and distributed ledger application– as well as the parties that host the software system and ensure its effectiveness. Based on theories of e-commerce, business networks, and trust, we explore relations between trust and Blockchain design. We analyze three case studies of Blockchain applications in the diamond industry. In each case we study two complementary research questions: (1) how does the blockchain application influence trust, and (2) how do trust based requirements affect the design of a blockchain application? We formulate two propositions and find dynamic interactions between trust requirements, blockchain application design, and transaction trust.

Kun Hao, Junchang Xin, Zhiqiong Wang, Guoren Wang

No abstract is available for this record.

Weidong Fang, Wei Chen, Wuxiong Zhang, Jun Pei · 6 authors

Abstract Blockchain, as one of the most promising technology, has attracted tremendous attention. The interesting characteristics of blockchain are decentralized ledger and strong security, while non-repudiation is the important property of information security in blockchain. A digital signature scheme is an effective approach to achieve non-repudiation. In this paper, the characteristics of blockchain and the digital signature to guarantee information non-repudiation are firstly discussed. Secondly, the typical digital signature schemes in blockchain are classified and analyzed, and then the state-of-the-art digital signatures are investigated and compared in terms of application fields, methods, security, and performance. Lastly, the conclusions are given, and some future works are suggested to stir research efforts in this field. Our works will facilitate to design efficient and secure digital signature algorithms in blockchain.

Duo Wang, Xin Huang, Xiaofeng Ma

Smart contracts increasingly cause attention for its ability to widen blockchain's application scope. However, the security of contracts is vital to its wide deployment. In this article, we propose a multilevel smart contract modeling solution to analyze the security of contract. We improve the program logic rules for bytecode and apply the Hoare condition to create a Colored Petri Net (CPN) model. The model detection method provided by the CPN tools can show the full-state space and the wrong execution path, which help us analyze the security of the contract from several perspectives. The example shows that the counter-example path given by the contract model is accord with our expected results based on code analysis, proving the correctness of the solution. In addition, we design a highly automated modeling method, introducing custom call libraries and a path derivation algorithm based on backtracking, which improves the efficiency and pertinence of the dynamic simulation of CPN models.

Nadeem Abdullah Malibari

Researchers and practitioners continue to draw varied interest on blockchain (BC) technology. The concept is generally attributed to its outstanding features such as decentralization, reliability, security and data veracity. However, even with the growing interest, a lot has to be done concerning the modern state of knowledge and practice in relation to the use of BC technology in education. Therefore, this survey presents a review of the existing studies on BC-based learning applications. The survey is centered on three major themes: learning applications that have been made using BC technology, the contribution and merits of blockchain technology to the education sector, and the problems experienced while integrating BC technology in learning. An intensive discussion is presented as well as a comprehensive result analysis of each theme. The survey also highlights the key areas in education that stand to benefit from the incorporation of the blockchain technology.

Sheng Cao, Xiaosong Zhang, Rixin Xu

Cloud-based eHealth systems enable patients and medical institutions to manage their EHRs in a flexible and efficient way. Since EHRs are the most sensitive data for people and have significant value to adversaries, outsourced EHRs suffer from both internal and external threats. In this article, we first identify the threats toward the security of outsourced EHRs and present system and security criteria that a secure cloud-based eHealth system should achieve. Then we provide a blockchain-assisted eHealth framework for securing outsourced EHRs that meets the identified criteria. We also show a case study where the blockchain technology is applied to ensure the security of outsourced EHRs. Finally, we discuss several promising issues and research directions on blockchain-assisted secure EHRs in cloud-based eHealth systems.

Bo Wu, Ke Xu, Qi Li, Shoushou Ren · 6 authors

Collaborative edge computing (CEC) is a novel extension for several edge paradigms (e.g., mobile edge computing, fog computing, and cloudlet) to further enhance processing capabilities to support computation-intensive and latency-sensitive applications in edge-centric networks. While existing schemes keep adding new functionalities (e.g., collaborative computing and caching), they overlook an important issue of establishing trustworthiness among all CEC participants. In general, due to the heterogeneity of all participants, simply assuming trustworthiness among them is undesirable. To address this issue, in this article, we present BlockEdge, a blockchain-powered framework that delivers trusted CEC services. Toward this end, BlockEdge first introduces incentive schemes to attract edge nodes to participate in CEC tasks. Then it publicly and persistently stores all task results on blockchain to enable smart-contract-based correctness verification and automated punishment in case of failures. Such a built-in accountability scheme allows BlockEdge to establish a trust reputation system for all CEC stakeholders, which can be further used for reliable selection of CEC participators. Our security analysis and experimental evaluation demonstrate that BlockEdge is both technically feasible and financially beneficial. We hope that the blockchain-based trustworthiness establishment designed in BlockEdge can provide a fundamental primitive for building a more secure collaborative ecosystem, especially for complex networks such as 5G and IoT.

Ujjal Marjit, Prabhakar Kumar

Open Educational Resources (OER) play a pivotal role in the traditional teaching learning processes. So far, there are several problems in the conventional OER such as tracking and tracing of OER, proper attribution, sustainability, publishing time and single point of failure due to its centralized nature. This paper proposes a Ethereum blockchain based decentralized and distributed framework to alleviate the problems existing in present OER. In addition Interplanetary File System (IPFS) has been included in this proposed system for storing the hypermedia as distributed way. It reduces the storage time. In this paper, we design distributed and decentralized infrastructure for OER system that remedies all of these drawbacks through the use of the Ethereum blockchain platform.

Samuel Masseport, Jorick Lartigau, Benoît Darties, Rodolphe Giroudeau

No abstract is available for this record.

Olumide Malomo, Danda B. Rawat, Moses Garuba

Abstract The survivability of any organization in the event of disaster or attack could greatly depend on its offsite data recovery. But which provider could offer secure and resilient cyber security protection to offsite data is a major problem for individuals, businesses and organizations. In recent times, cyber-attacks are strategic and tactical. Adversaries are advanced with capability to access sensitive business digital assets. Their nefarious actions have exposed devastating flaws in many access controls at different levels, and are now security risk to systems, data storages and resources. In this paper, we present a Blockchain enabled federated cloud computing framework, to secure storage for offsite digital assets. Our framework is designed with a great degree of efficiency, privacy, scalability and restricted access control. It addresses authentication flaws and improve early detection of data breaches, by continuously evaluating subject’s access control and interaction with resources, using operation cost for monitoring and accountability. Evaluation showed proof of concept that our design and approach outperforms the traditional approaches.

Nikolaos Kapsoulis, Alexandros Psychas, Georgios Palaiokrassas, Achilleas Marinakis · 6 authors

Enterprise blockchain solutions attempt to solve the crucial matter of user privacy, albeit that blockchain was initially directed towards full transparency. In the context of Know Your Customer (KYC) standardization, a decentralized schema that enables user privacy protection on enterprise blockchains is proposed with two types of developed smart contracts. Through the public KYC smart contract, a user registers and uploads their KYC information to the exploited IPFS storage, actions interpreted in blockchain transactions on the permissioned blockchain of Alastria Network. Furthermore, through the public KYC smart contract, an admin user approves or rejects the validity and expiration date of the initial user’s KYC documents. Inside the private KYC smart contract, CRUD (Create, read, update and delete) operations for the KYC file repository occur. The presented system introduces effectiveness and time efficiency of operations through its schema simplicity and smart integration of the different technology modules and components. This developed scheme focuses on blockchain technology as the most important and critical part of the architecture and tends to accomplish an optimal schema clarity.

Lei Hang, Do‐Hyeun Kim

With the gradual popularization of Internet-of-Things (IoT) applications and the development of wireless networking technologies, the use of heterogeneous devices and runtime verification of task fulfillment with different constraints are required in real-world IoT scenarios. As far as IoT systems are concerned, most of them are built on centralized architectures, which reveal various assailable points in data security and privacy threats. Hence, this paper aims to investigate these issues by delegating the responsibility of a verification monitor from a centralized architecture to a decentralized manner using blockchain technology. We present a smart contract-based task management scheme to provide runtime verification of device behaviors and allows trustworthy access control to these devices. The business logic of the proposed system is specified by the smart contract, which automates all time-consuming processes cryptographically and correctly. The usability of the proposed solution is further demonstrated by implementing a prototype application in which the Hyperledger Fabric is utilized to implement the business logic for runtime verification and access control with one desktop and one Raspberry Pi. A comprehensive evaluation experiment is conducted, and the results indicate the effectiveness and efficiency of the proposed system.

Marwan Adnan Darwish, Eiad Yafi, Mohammed A. Al Ghamdi, Abdullah Almasri

No abstract is available for this record.

M. Sumathi, S. Sangeetha

In earlier banking systems, the data owners were unable to access or update their financial information. Nowadays, user financial information is stored in Cloud storage instead of traditional storage, but security risks are high in financial sectors. Sometimes, Cloud services providers and public auditors modify the user sensitive attribute values. Hence, the decentralized storage system is required for providing better security and integrity of user sensitive attribute values. Blockchain is a decentralized technology for providing tamper-proof storage for sensitive attribute values. Hence, the account holder information is segregated as sensitive and non-sensitive attributes. Before storing into off-chain mode of blocks, the sensitive attributes are grouped into ‘n' number of groups and encrypted by separate group key. The non-encrypted, non-sensitive attributes are stored in cloud storage. The access information is stored in the on-chain mode of the block for easy monitoring. Hence, the security and integrity of sensitive information are preserved.

Maurizio Talamo, Franco Arcieri, Andrea Dimitri, Christian H. Schunck

Public key infrastructures (PKIs) are the cornerstone for the security of the communication layer of online services relying on certificate-based authentication, such as e-commerce, e-government, online banking, cloud services, and many others. A PKI is an infrastructure based on a hierarchical model, but the use of PKIs in non-hierarchical contexts has exposed them to many types of attacks. Here, we discuss weaknesses exploited in past attacks and we propose a solution based on an original consensus algorithm developed for use on blockchain technology. In this implementation we retain the full functionality around X.509 certificates, i.e., for the triad (server name, server address, X.509 server certificate), and demonstrate a mechanism for obtaining fast consensus. The main properties of the solution are that a consensus may be reached even when not all members of the involved PKI participate in a transaction, and that no advanced trust agreement among PKIs is needed. The proposed solution is able to detect PKI attacks and can distinguish errors from attacks, allowing precise management of anomalies.

Jinbeom Seo, Youngbok Cho

In this paper, we use the blockchain to manage our own medical information on our own and to maintain data integrity where data can be changed without our approval. This paper proposes a system that can solve the problem of costly repetition of expensive medical imaging and make more accurate diagnosis by sharing one image with various experts.

B Ravishankar, Prateek Kulkarni, M.V. Vishnudas

Data is nowadays an invaluable resource; indeed, it guides all business decisions in most of the computer-aided human activities. Threats to data integrity are thus of paramount relevance, as tampering with data may maliciously affect crucial business decisions. This issue is especially true in cloud computing environments, where data owners cannot control fundamental data aspects, like the physical storage of data and the control of its accesses. Blockchain has recently emerged as a fascinating technology which, among others, provides compelling properties about data integrity. Using the Blockchain to face data integrity threats seems to be a natural choice, but its current limitations of low throughput, high latency, and weak stability hinder the practical feasibility of any Blockchain-based solutions. In this paper, by focusing on a case study from the European SUNFISH project, which concerns the design of a secure by-design cloud federation platform for the public sector, we precisely delineate the actual data integrity needs of cloud computing environments and the research questions to be tackled to adopt Blockchain-based databases. First, we detail the open research questions and the difficulties inherent in addressing them. Then, we outline a preliminary design of an effective Blockchain-based database for cloud computing environments.

Kausthav Pratim Kalita, Debojit Boro, Dhruba K. Bhattacharyya

Due to the scalability factor associated with a blockchain, it is inevitable that it will grow with time. Therefore, one of the primary concerns associated with a blockchain is its growing size as more blocks are introduced into the chain. When a full node or a mining node joins a blockchain network, it requires downloading all the existing information available in the distributed chain before it can add new blocks. Thus, as time progresses and more blocks are appended to the chain, a large amount of information needs to be replicated in its local machine. We introduce an approach to keep a minimally shared blockchain in the network which keeps the size of the distributed ledger limited and, thus, new miners can participate in the mining process at a faster pace.

N. S. Akhilesh, M. N. Aniruddha, K.S. Sowmya

Blockchain is a distributed database or a decentralized ledger which is most commonly used to exchange digital currency and perform transactions securely. Every participant of the network has access to the ledger which will be updated by every new transaction. The Blockchain ledger is a collection of all transactions executed in the past. The Blockchain ledger is a continuously growing tamper-proof data structure containing blocks that hold batches of individual transactions. The completed blocks are added in chronological order. Blockchain via Bitcoin has had a massive impact on the world in the past decade and it's safe to say that this will continue, especially with many people working tirelessly to remove the various limitations that are prohibiting blockchains from becoming mainstream. One such limitation is the high processing and electrical costs that come from the Proof-of-Work consensus protocol. In this paper, we propose an alternative proof-by-approval protocol which is a more advanced form of the proof-of-reputation protocol, that offers better security and is a more decentralized approach than the former at the cost of being less performant and harder to setup.