Distributed systems play a central role in modern computing, providing scalability, reliability, and fault tolerance. However, ensuring data availability in such systems remains a critical challenge, particularly in the face of attacks like data corruption, denial-of-service, and data loss. Cryptographic techniques can play a pivotal role in securing the availability of data by ensuring both data integrity and access control. This paper explores various cryptographic mechanisms, including hash functions, digital signatures, and distributed ledger technologies like blockchain, to enhance the reliability and availability of data in distributed systems. The study also discusses challenges in implementing these techniques in large-scale distributed environments and suggests strategies for future improvements
Foteini Baldimtsi, Panagiotis Chatzigiannis, Steven Gordon, Phi Hung Le · 5 authors
We present gOTzilla, a protocol for interactive zero-knowledge proofs for very large disjunctive statements of the following format: given publicly known circuit C, and set of values Y = {y1 , . . . , yn }, prove knowledge of a witness x such that C(x) = y1 ∨ C(x) = y2 ∨ · · · ∨ C(x) = yn . These type of statements are extremely important for the proof of assets (PoA) problem in cryptocurrencies where a prover wants to prove the knowledge of a secret key sk that associates with the hash of a public key H(pk) posted on the ledger. We note that the size of n in popular cryptocurrencies, such as Bitcoin, is estimated to 80 million. For the construction of gOTzilla, we start by observing that if we restructure the proof statement to an equivalent of proving knowledge of (x, y) such that (C(x) = y) ∧ (y = y1 ∨ · · · ∨ y = yn )), then we can reduce the disjunction of equalities to 1-out-of-N oblivious transfer (OT). Our overall protocol is based on the MPC in the head (MPCitH) paradigm. We additionally provide a concrete, efficient extension of our protocol for the case where C combines algebraic and non-algebraic statements (which is the case in the PoA application). We achieve an asymptotic communication cost of O(log n) plus the proof size of the underlying MPCitH protocol. While related work has similar asymptotic complexity, our approach results in concrete performance improvements. We implement our protocol and provide benchmarks. Concretely, for a set of size 1 million entries, the total run-time of our protocol is 14.89 seconds using 48 threads, with 6.18 MB total communication, which is about 4x faster compared to the state of the art when considering a disjunctive statement with algebraic and non-algebraic elements.
A non-fungible token (NFT) is a unit of data on what is known as a blockchain digital ledger, where each token can represent a unique piece of digital data. Since they are not interchangeable, non-homogeneous tokens can represent digital files, such as paintings, sounds, movies, projects in games, or other forms of creative work. Blockchain allows users on the C or B side to place personal data or business data on the blockchain network, instead of homogenous token, thus becoming the next hot spot in the Internet industry. 2021 was perhaps the most critical year for the industry so far. In this paper, 2020 can be defined as a year of construction and preparation, which saw great progress and positive results on the most important indicators and macro indicators for the industry. There are more wallets and transactions interacting with DApps than ever before, and the demand for NFT and games has increased dramatically.
Avni Rustemi, Vladimir Atanasovski, Aleksandar Risteski
Blockchain nowadays is finding great application in many areas, based on its security, decentralized mode of operation, however many things during its use remain challenging include the issue of data privacy, such as safe and effective data management, maintaining data integrity and data quality, etc. Through this paper we will try to make an overview of existing blockchain technologies, their use today and sublimating existing and future trends. We will briefly describe application of blockchain technology in various fields suggesting solutions, advantages and disadvantages of blockchain, cloud platforms for blockchain data storage. We will focus on data privacy by making a description of the strategies used in this regard. We will conclude the paper by giving the latest research regarding data storage, the importance of data storage and our views regarding the future of data management and storage.
With the rapid development of blockchain technology, it provides a new technical solution for secure storage of data and trusted computing. However, in the actual application of data traceability, blockchain technology has an obvious disadvantage: the large amount of data stored in the blockchain system will lead to a long response time for users to query data. Higher query delay severely restricts the development of block chain technology in the traceability system. In order to solve this problem, we propose an efficient, secure and low storage overhead blockchain query scheme. Specifically, we design an index structure independent of Merkle tree to support efficient intra-block query, and create new fields in the block header to optimize inter-block query. Compared with several existing schemes, our scheme ensures the security of data. Finally, we simulate and evaluate our proposed scheme. The results show that the proposed scheme has better execution efficiency while reducing additional overhead.
Nada Elsokkary, Muhammad Habib ur Rehman, Sabah Suhail, Hermann Kaindl · 5 authors
Despite a recent increase in popularity, most individuals remain hesitant to use cryptocurrencies due to concerns about their volatility, general lack of understanding of blockchain technology, and various trust issues. Therefore, it is of high priority for the community to better understand such systems, and what increases or decreases trust in them. In this paper, we explore the current trust-related requirements on blockchain systems, focusing on the use of the dedicated requirements elicitation method TrUStAPIS. We evaluate Bitcoin and Diem trust issues and requirements. Based on the evaluation, we present a cryptocurrency trust model.
With the enormous amount of data produced daily, cloud and fog computing presented efficient and effective models for real-time data exchange. Nevertheless, this technology came with a cost at the security level, where it became an easy target for malicious actions that could directly spread throughout the model. Blockchain, a recent and promising technology, was a suitable solution for securing the transactions in the fog environment because of the distributed ledger structure that makes it resistant to many attacks. Scalability, however, introduced the main drawback for a blockchain by making it inefficient in some real-world applications, especially in the medical field, which includes a lot of data exchange. This work will suggest a scalable and secure model for fog and cloud computing in healthcare systems that depend on sidechains and the clustering of the available fog nodes. The importance of the model is highlighted, and experimental results showed promising outcomes.
The dominance of a few big companies in the storage market arising various concerns including single point of failure, privacy violation, and oligopoly. To eliminate the dependency on such a centralized storage architecture, several Decentralized Storage Network (DSN) schemes such as Filecoin, Sia, and Storj have been introduced. DSNs leverage blockchain technology to create a storage platform such that the micro storage providers can also participate in the storage market. To verify the accurate data storage by the storage providers during a storage contract, DSNs apply a Proof of Storage (PoS) scheme to continuously inspect the storage service. However, continuous verification of the storage provider imposes an extra cost to the network and therefore end-users. Moreover, DSN's PoS verification is vulnerable to a service denying attack in which the storage provider submits valid PoS to the network while denying the service to the client. Considering the benefits and existing challenges of DSNs, this paper introduces a novel incentive-compatible DSN scheme. In this scheme, the PoS is conducted only if the client submits a challenge request. We model the storage service as a non-cooperative repeated dynamic game and set the players' payoffs such that the storage provider's dominant strategy is to honestly follow the storage contract. Our proposed mechanism leverages the smart-contract and oracle network to govern the storage agreement between the client and storage provider efficiently. Furthermore, our scheme is independent of a specific blockchain platform but can be plugged into any blockchain platform with smart-contract execution capability. As a proof of concept, we have implemented our scheme using solidity language and chainlink oracle network. The performance analysis demonstrates the applicability of our scheme. The outcome of this paper is a new incentive-compatible mechanism designed carefully for the blockchain-based DSN. The proposed mechanism utilizes different tools including game-theory, smart-contract, oracle network, and Merkle tree to improve the security and performance of storage verification in DSN.
In industrial and academic working environments, illegitimate academic certificates have been prepared by individuals who aim to be employed without completing regulated training and education programs. This violation has made an unjust confusion between genuine and fake certificates. Within the hiring process, employers thus need a reliable mechanism for verifying academic certificates that ensures the integrity of data. In accordance with this aim, blockchain technology has been introduced and deployed at some universities supporting fraud prevention or secure access to certificates. However, the method of handling knowledge in these educational systems was not investigated devotedly. This paper introduces an authentication framework of educational certificates that employed blockchain and ontology technologies, named BOCA. The learning ontology (LeOn), which was used to represent the central knowledge model of the system, was assigned to semantically manage the domain knowledge and link the educational data to the blockchain network. The system features, including the working process, the LeON ontological development, and the rule base construction, are described in detail. The system deployment on Hyperledger Fabric yielded promising experimental results. Ongoing work focuses on improving system performance and allowing semantic search on data blocks.
Kirtirajsinh Zala, Hiren Kumar Thakkar, Rajendrasinh Jadeja, Neel H. Dholakia · 7 authors
Traditional healthcare services have changed into modern ones in which doctors can diagnose patients from a distance. All stakeholders, including patients, ward boy, life insurance agents, physicians, and others, have easy access to patients' medical records due to cloud computing. The cloud's services are very cost-effective and scalable, and provide various mobile access options for a patient's electronic health records (EHRs). EHR privacy and security are critical concerns despite the many benefits of the cloud. Patient health information is extremely sensitive and important, and sending it over an unencrypted wireless media raises a number of security hazards. This study suggests an innovative and secure access system for cloud-based electronic healthcare services storing patient health records in a third-party cloud service provider. The research considers the remote healthcare requirements for maintaining patient information integrity, confidentiality, and security. There will be fewer attacks on e-healthcare records now that stakeholders will have a safe interface and data on the cloud will not be accessible to them. End-to-end encryption is ensured by using multiple keys generated by the key conclusion function (KCF), and access to cloud services is granted based on a person's identity and the relationship between the parties involved, which protects their personal information that is the methodology used in the proposed scheme. The proposed scheme is best suited for cloud-based e-healthcare services because of its simplicity and robustness. Using different Amazon EC2 hosting options, we examine how well our cloud-based web application service works when the number of requests linearly increases. The performance of our web application service that runs in the cloud is based on how many requests it can handle per second while keeping its response time constant. The proposed secure access scheme for cloud-based web applications was compared to the Ethereum blockchain platform, which uses internet of things (IoT) devices in terms of execution time, throughput, and latency.
Miodrag J. Mihaljević, Lianhai Wang, Shujiang Xu, Milan Todorović
This paper proposes an approach for pool mining in public blockchain systems based on the employment of a recently reported consensus protocol with the puzzle based on a symmetric encryption that provides an energy–space trade-off and reduces energy consumption. The proposed architecture employs a pseudo-symmetric allocation of the resources for the blockchain consensus protocol and provides protection against certain malicious actions of the pool members, as well as a miner’s opportunity for selecting the resources required for participation in the consensus protocol. Given that the considered consensus protocol employs two resources, the proposed architecture uses this two-dimensional nature to provide resistance against block withholding and selfish mining attacks, as well as a reduction in energy spending as a trade-off with the employment of certain memory resources. The high resistance of the proposed pool mining approach against the considered attacks appears to be a consequence of the success probability of the pool in comparison with the success probability of malicious miners. Assuming appropriate selection of the puzzle hardness, the probability that malicious miners can solve the puzzle without the support of the pool manager can be arbitrarily small. Implementation of the proposed approach on a modified Ethereum platform and experimental evaluation issues have also been reported. The conceptual novelty of the proposed pool mining approach is the following: Instead of separation of the blockchain consensus protocol and control of pool miners honest work, this paper proposes an approach where honest work of miners and pool managers is provided by a dedicated application of the considered consensus protocol. Advantages of the proposal in comparison with the previously reported ones include the following: (i) high resistance against block withholding and selfish mining attacks without an additional security procedure; (ii) reduction in the energy required, and at the same time preservationthe security of the consensus protocol; (iii) flexibility of the pool miners regarding selection of the resources that should be employed providing a trade-off between required energy and memory resources. The proposed architecture was implemented employing a dedicated modification of the Ethereum platform and the performed experiments confirmed the feasibility and effectiveness of the proposal.
Threats towards information systems have continued to increase and become more sophisticated, making security approaches a necessity for all types of organizations to ensure their protection. To implement an appropriate computer security policy, it is necessary to efficiently exploit the data that has become a valuable asset for these security systems, provided it is well used, controlled and monitored.In this paper, we focus on developing a decentralized solution based on Blockchain technology and IPFS (InterPlanetary File System) that can maintain and ensure the integrity of log files and sensitive information. The obtained results are promising, we obtained a distributed ledger of all log file transactions in a chronological sequence, which was shared among all Ethereum participants, allowing us to verify the log files' integrity, validity, and auditability throughout their life cycle.
Wattana Viriyasitavat, Li Da Xu, Gaurav Dhiman, Zhuming Bi
Blockchain technology (BCT) has brought a paradigm shift to Business Process Management (BPM). BCT provides a trusted decentralized infrastructure to secure data and process executions using distributed ledgers and smart contract to manage complex business processes. Numerous efforts have been made to exploit BCT in supporting dynamic and trusted collaborations of business processes. This paper aims to understand recent BCT development for its BPM applications and identify the limitations and challenges for further development via a systematic literature review (SLR). It is found that numerous works have reported using BCT as technical solutions to fulfill some traditional BPM functions. This paper is distinguished from existing works, especially several relevant surveys in the sense that (1) the impact of using BCT in BPM is thoroughly explored to identify new constraints and challenges explicitly brought by blockchains; (2) the requirements for Business Process Compliance (BPC) are firstly analyzed in detail. Note that BPC is to assure the adherence of business processes to pre-defined policies, standards, specifications, regulations, and laws when business processes are executed. To fill the gaps of BCT applications in these two aspects, Blockchain-as-a-Service (BCaaS) is adopted in business process architecture, and the trends of BCT developments are identified accordingly.
M S Kiu, Kai Wen Lai, Fah Choy Chia, Phui Fung Wong
Purpose The digitization of electronic document management (EDM) in the construction industry has become more common in nature with the evolution of technology. However, there are still some limitations in EDM in the common data environment which can be improved with the integration of blockchain technology. The purpose of this paper is to identify the limitations of the current EDM system in the construction industry, to determine the potential of blockchain in improving the EDM system in the construction industry and challenges towards blockchain-based EDM. Design/methodology/approach Semi-structured interviews were conducted with nine (9) respondents with background from the construction industry and blockchain expertise. Content analysis was used to analyze the primary data. Findings Current EDM system in the construction industry possessed limitations such as system maturity, high cost, slow adoption of technology and security concerns. Blockchain is able to make improvements in the current EDM system in terms of data integrity, data tracking, data immutability, data security, data trustability, and data accountability. Several challenges such as costs, blockchain scalability and industry knowledge, industry culture and hardware need to overcome prior blockchain-based EDM systems can be widely applied in the construction industry. Originality/value The research findings provide insight on future EDM in the construction industry and aids future research in this field.
Aniruddha Bhattacharjya, Kamil Kozdrój, Grzegorz Bazydło, Remigiusz Wiśniewski
The Internet of Medical Things (IoMT) global market has grown and developed significantly in recent years, and the number of IoMT devices is increasing every year. IoMT systems are now very popular and have become part of our everyday life. However, such systems should be properly protected to preventing unauthorized access to the devices. One of the most popular security methods that additionally relies on real-time communication is Blockchain. Moreover, such a technique can be supported by the Trusted Third Party (TTP), which guarantees data immutability and transparency. The research and industrial community has predicted the proliferation of Blockchain-based IoMT (BIoMT), for providing security, privacy, and effective insurance processing. A connected environment comprises some of the unique features of the IoMT in the form of sensors and devices that capture and measure, recognize and classify, assess risk, notify, make conclusions, and take action. Distributed communication is also unique due to the combination of the fact that the Blockchain cannot be tampered with and the Peer-to-Peer (P2P) technique, especially compared to the traditional cloud-based techniques where the reliance of IoMT systems on the centralized cloud makes it somewhat vulnerable. This paper proposes a Blockchain-based technique oriented on IoMT applications with a focus on maintaining Confidentiality, Integrity, and Availability (the CIA triad) of data communication in the system. The proposed solution is oriented toward trusted and secure real-time communication. The presented method is illustrated by an example of a cloud-based hospital application. Finally, the security aspects of the proposed approach are studied and analyzed in detail.
In order to protect data privacy in the context of big data, a new scheme to protect data privacy and user privacy is proposed. This study believes that blockchain technology can be used to build a massive private data retrieval and sharing platform, considering the realization of privacy protection under horizontal federated learning and vertical federated learning, combined with privacy computing technology, to verify the results of massive data retrieval, and to build a "data availability that is not available." The "visible" security reduction model involves three cryptographic algorithms, namely functional encryption, zero-knowledge proof and asymmetric encryption. By combining blockchain and cloud servers, a hybrid storage architecture with data storage on the chain and off-chain storage is realized. And use function encryption and zero-knowledge proof to achieve privacy protection and secure data sharing of verifiable results. The final experimental results prove that the security feasibility of this model is proposed in this paper, which can fully improve the level of data log security management, operation and maintenance supervision, and the quality and efficiency of data security protection, and improve the network security protection system of the power grid in all scenarios.
The emergence of metaverse brings tremendous evolution to Non-Fungible Tokens (NFTs), which could certify the ownership the unique digital asset in the cyber world. The NFT market has garnered unprecedented attention from investors and created billions of dollars in transaction volume. Meanwhile, securing NFT is still a challenging issue. Recently, numerous incidents of NFT theft have been reported, leading to incalculable losses for holders. We propose a decentralized NFT anti-theft mechanism called TokenPatronus, which supports the general ERC-721 standard and provide the holders with strong property protection. TokenPatronus contains pre-event protection, in-event interruption, and post-event replevin enhancements for the complete NFTs transactions stages. Four modules are designed to make up the decentralized anti-theft mechanism, including the decentralized access control (DAC), the decentralized risk management (DRM), the decentralized arbitration system (DAS) and the ERC-721G standard smart contract. TokenPatronus is performing on the Turtlecase NFT project of Ethereum and will support more blockchains in the future.
Abstract Cloud services are distributed from manifold sources with autonomous security procedures. The conventional authentication methods result in asynchronous security towards multi‐resource access and sharing. This provides volatile authentication for sequential service sessions. For alleviating this issue, a Rendezvous Block‐based Authentication Framework (RBAF) is proposed. This framework is backboned with a blockchain paradigm that differentiates authentication based on rendezvous and asynchronous attributes. The modifications in initial and final attributes are observed, intended for training, and supplanted with service‐dependent authentications. In the different sessions, attribute‐based authentication and agreed end‐to‐end security are administered using agreed keys that are valid within the sessions. This key generation is modified using the new session and user attributes based on learning recommendations. The ledger paradigm records the session and its associated attributes for different training instances, based on which service flexibility is ensured. The proposed framework's performance is verified using the metrics service distribution ratio, false rate, session uptime, and service delay.
With the increase of data stored on the blockchain, the efficiency of storage and calculation of blockchain has gradually become a bottleneck restricting the development of blockchain. By storing data on multiple chains, blockchains can request data from other chains for calculation and the storage pressure can be alleviated. But the transfer of a large amount of data between chains suffers from low transfer efficiency and poor security. A reasonable design is to perform the calculation on the data storage chain and only transfer the results across chains. However, since the calculation process is invisible, blockchains cannot judge the consistency of calculation results from other chains. In this paper, we provide a blockchain-enabled decentralized consistency verification scheme for cross-chain calculation (BeDCV). Considering the decentralized characteristic of blockchain, we adopt the blockchain calledsupervision chainfor decentralized auditing. We modify paillier homomorphic encryption to encrypt data involved in the calculation for correctness verification. Then, we aggregate the ciphertexts of data to generate the audit proof for integrity verification. Besides, we verify whether the data involved in the calculation are real-time by leveraging a counting bloom filter. The supervision chain can check the correctness, integrity, and real-time performance of cross-chain data calculation without revealing any original information about the data. The theoretical and experimental analysis demonstrates that BeDCV can verify the consistency of cross-chain data calculation result effectively, realizing secure and reliable expansion of blockchain.