Philipp Frauenthaler, Michael Borkowski, Stefan Schulte
The suitability of a blockchain for a given use case mainly depends on the user's requirements and on the blockchain's functional and non-functional properties. Requirements and a blockchain's properties may change over time, and thus, a selected blockchain may become unsuitable for a given use case. Such uncertainties pose significant risks for developers. In this paper, we present a framework that allows developers to define functional and non-functional requirements, monitors several blockchains and, based on the specified requirements, selects the best-fitting blockchain for a particular use case. If another blockchain becomes more appropriate during runtime, the framework enables a switchover to this blockchain. Our evaluation using a reference implementation shows that switching to another blockchain can save cost and enable developers to benefit from better performance and a higher level of trust.
Healthcare records management system has been revolutionized over the last decade aiming to provide accurate, efficient and enhanced patient care. The existing management system is either based on a client/server approach where each hospital maintains its own database or on a cloud approach where the health records are stored in a cloud server and managed by a third-party cloud service provider. However, these approaches suffer from the issues of security, privacy, data vulnerability and fragmentation. Furthermore, healthcare providers and patients are unable to have a unified view of a patient's medical history from all visited medical care centers. This results in additional treatment costs, repeated medical tests and increased time to diagnosis. The data traceability, immutability, transparency, replication, security and privacy traits of the emerging blockchain technology have a promising potential in the healthcare domain addressing these issues. In this paper, we propose BlockHR, a patient-centric healthcare records management system for efficient medical care at an optimal cost. The system enables healthcare providers to enter the patients' medical record data to the blockchain network and allows patients to enter their social data such as sleeping habits, physical activities, and current location. Consequently, BlockHR provides support to doctors for better diagnosis and prognosis. We evaluate the performance of BlockHR in terms of execution time and the total amount of data transferred for ledger update with an increasing number of hospitals and blocks in the network.
Artificial intelligence (AI) has a limitation in that it is only in the passive cognition area, so its operating process is not transparent; therefore, the technology relies on learning data. Since raw data for AI learning are processed and inspected manually to assure high quality for sophisticated AI learning, human errors are inevitable, and damaged and incomplete data and differences from the original data may lead to unexpected outputs of AI learning for which processed data are used. In this context, this research examines cases where AI learning data were inaccurate, in terms of cybersecurity, and the need for learning data management before machine learning through analysis of cybersecurity attack techniques, and we propose the direction of establishing a data-preserving AI system, which is a blockchain-based learning data environment model to verify the integrity of learning data. The data-preserving AI learning environment model is expected to prevent cyberattacks and data deterioration that may occur when data are provided and utilized in an open network for the processing and collection of raw data.
Digital identity is one of the biggest challenges in cyberspace. This field has been evolving for many decades with a number of Identity Management (IDM) models being proposed and employed; however, few were able to solve the issue of sovereignty of an identity and storage-control of its associated personal and confidential data. Self-Sovereign Identity (SSI) was introduced to solve this crucial issue offering a user full sovereignty of their identity and storage-control of their associated personal and confidential data. Alongside ownership of an identity, it maintains all private information in a Digital Wallet which is owned and controlled by the user. However, SSI is an emerging IDM, therefore it requires careful evaluation of various aspects of SSI for it to become an operative IDM. This paper proposes several specifications to evaluate any SSI solution. Subsequently, it analyses two emerging SSI solutions uPort and Sovrin. Finally, an evaluation of uPort and Sovrin SSI is performed utilising the proposed specifications, highlighting their strengths and limitations.
Marcel Müller, Sandro Rodriguez Garzon, Axel Küpper
In e-commerce, buyers and sellers trade digital products without knowing each other personally. Due to the lack of trust, a buyer prefers to pay for a product upon receipt. Also, the seller prefers to send a product after receiving the payment. With trusted escrows as intermediaries, the payment can be processed and independent parties can confirm the authenticity of a digital product before completing the trade. However, concerning the trade of digital goods, current escrow-based solutions for the buyer-seller dilemma are prone to digital theft because they require the intermediary to validate the complete digital product. Moreover, buyers and sellers rely on the judgment of a single intermediary that they have to trust fully. This work presents a consensus-based oracle protocol for the secure and transparent trade of digital goods using a decentralized escrow service. It protects the seller and buyer against digital theft by splitting the digital product into fragments. Independent parties confirm the authenticity of each of these fragments via a distributed ledger. The protocol is designed to ensure non-fraudulent behavior among all participants and to compensate validators for their work. Compensations are distributed to the validators according to their stake, their confidence and the overall outcome of the validity check.
Sylvain Chatel, Apostolos Pyrgelis, Juan Ramón Troncoso-Pastoriza, Jean‐Pierre Hubaux
In the digital era, users share their personal data with service providers to obtain some utility, e.g., access to high-quality services. Yet, the induced information flows raise privacy and integrity concerns. Consequently, cautious users may want to protect their privacy by minimizing the amount of information they disclose to curious service providers. Service providers are interested in verifying the integrity of the users' data to improve their services and obtain useful knowledge for their business. In this work, we present a generic solution to the trade-off between privacy, integrity, and utility, by achieving authenticity verification of data that has been encrypted for offloading to service providers. Based on lattice-based homomorphic encryption and commitments, as well as zero-knowledge proofs, our construction enables a service provider to process and reuse third-party signed data in a privacy-friendly manner with integrity guarantees. We evaluate our solution on different use cases such as smart-metering, disease susceptibility, and location-based activity tracking, thus showing its versatility. Our solution achieves broad generality, quantum-resistance, and relaxes some assumptions of state-of-the-art solutions without affecting performance.
There is a great interest in many approaches towards blockchain in providing a solution to record transactions in a decentralized way. However, there are some limitations when storing large files or documents on the blockchain. In order to meet the requirements of storing relatively large data, a decentralized storage medium is produced. IPFS is a distributed file system which is content-addressable. It works very similar to the blockchain network. There are some attempts which take advantage of the blockchain concept and IPFS to design new approaches. Unfortunately, there are some inefficiencies in sharing data using the combination of IPFS and blockchain. In this paper, we proposed a secure file sharing system that brings a distributed access control and group key management by the adoption of the IPFS proxy. The IPFS proxy which plays an important role in the design is adopted to take responsibility for the control policies. The combination of the IPFS server and the blockchain network with the adoption of the IPFS proxy make a secure file sharing system which the members on the system can create new groups or join different groups by their own choice. Although there is no access control mechanism in IPFS server and blockchain network, the secure file sharing system manages the access control policies. The members access files only belong to the group they authorized.
Today's society is in constant transition to keep up with the ever evolving technological advances, which constantly challenge the traditional paradigms. One such being the fundamentals of governance. The current system of campus governance is running out of fuel; riddled with mishandled records, lack of transparency and unjustifiable time delays. In today's age of digitization and instantaneous transactions, the academic system has failed to keep up and is stuck in the clutches of legacy systems and bureaucracy. Also, the conventional labour intensive process makes it too easy for the students to tamper their original academic documents for employment. It is the need of the hour that today's academic institutes serve the fast moving needs of the education system with state-of-the-art technology. We propose a system for modern academic governance by harnessing the power of Blockchain technology. We demonstrate how Blockchain can ensure transparency and build back trust into the system while simultaneously ensuring speed of execution by discussing the pervasive use cases of student transcript verification, tender management and certificate verification and presenting an implementation of the same on the VJTI Blockchain.
Bhabendu Kumar Mohanta, Utkalika Satapathy, Meenu Rani Dey, Soumyashree S. Panda · 5 authors
Cyber-physical Systems (CPS) are reshaping the way of interaction with the physical world. Moreover, the true potential of CPS will be realized when a decentralized approach will be taken into account. Blockchain is an up-and-coming technology which can establish trust in CPS, where participants do not trust each other. Blockchain applications eliminate the middle man to provide trust and making the processes more efficient & cheaper. It's decentralized nature and cryptographic algorithm make it immune to attack and becomes a secure technology. When the data is stored on the blockchain it becomes immutable, ensuring trust in data. Nevertheless, this does not guarantee the trustworthiness of the device which is generating the data. We propose a blockchain-based signature storage solution to ensure trust among the participants which is further applicable to a diverse range of blockchain-based CPS applications. We have implemented our system using the Ethereum network and Docker Tools. Our proposed solution guarantees security properties i.e. device identification, authentication, integrity, and non-repudiation. Also, it reduces the storage space and storage cost than the traditional usage of blockchain in CPS.
Elie Kfoury, David Khoury, Ali AlSabeh, Jose Gomez · 6 authors
Blockchain technology is the cornerstone of digital trust and systems' decentralization. The necessity of eliminating trust in computing systems has triggered researchers to investigate the applicability of Blockchain to decentralize the conventional security models. Specifically, researchers continuously aim at minimizing trust in the well-known Public Key Infrastructure (PKI) model which currently requires a trusted Certificate Authority (CA) to sign digital certificates. Recently, the Automated Certificate Management Environment (ACME) was standardized as a certificate issuance automation protocol. It minimizes the human interaction by enabling certificates to be automatically requested, verified, and installed on servers. ACME only solved the automation issue, but the trust concerns remain as a trusted CA is required. In this paper we propose decentralizing the ACME protocol by using the Blockchain technology to enhance the current trust issues of the existing PKI model and to eliminate the need for a trusted CA. The system was implemented and tested on Ethereum Blockchain, and the results showed that the system is feasible in terms of cost, speed, and applicability on a wide range of devices including Internet of Things (IoT) devices.
M. Poongodi, Mounir Hamdi, Vijayakumar Varadarajan, Bharat S. Rawal · 5 authors
As a very appealing computing standard, cloud computing makes it feasible for resource constrained clients to experience rate effective and flexible resources at ease. In the prevailing systems, the conventional cloud storage scheme is bound to operate its primitive functions in centralized mode. This reason possess problems like data availability, information protection and excessive operational charge. With the improvement of block chain generation, the decentralized scheme has entered the general public view. Compared to contemporary and cutting edge cloud storage, they are predicted to be more scalable, secured and comfortable. But, the use of end-to-end encryption in a decentralized scheme, limits the search functionality as the existing searchable encryption methods are designed only for the centralized device. Moreover, the existing decentralized cloud storage doesn't restrict any data user to get access to all of the files for any keyword search made purposefully through them. Thus, in this manner, user integrity of files and keyword searches are compromised throughout the network. Therefore, as a manner to solve these complications, we systematically join techniques of encryption and hashing to furnish reliable keyword search over encrypted files in decentralized storage. Consequently using the block chain system, the architecture remains incorruptible and protects all the confidential files and keywords in a fully controlled file access environment.
Pavitra Haveri, U.B. Rashmi, D. G. Narayan, K. Nagaratna · 5 authors
Bitcoin and Cryptocurrencies are the most popular and the earliest applications of Blockchain. A Blockchain is a public ledger that is distributed and decentralized and it is used to carry out transactions online across the entire network of computer systems. It is a recent technology adopted for data security. The non-modifiable property of the blockchain helps to overcome the problem of document forgery. According to researches, about one million students graduate each year and the document issuing authorities have seemed to be compromised for the security credentials of student data. Due to a lack of effective anti-forge mechanism, forged documents often get unnoticed. The use of physical copies of documents creates a huge overhead as it involves manual verification, paper storage, and manual auditing. Various agencies fail to verify the authenticity of the documents and create loopholes. In this paper, in an attempt to solve the above problem, we design a multi-node private blockchain network using the Ethereum framework and create an off-chain storage i.e. private Interplanetary File System (IPFS) to store the documents. We also evaluate the performance of Ethereum blockchain by analysing the impact of various parameters such as varying difficulty level, load, network size, and consensus algorithms.
Outbreak of the Internet and technological dependence make the Cyber Technology Industry grow at a very fast pace. Cyber-security is the dire need of today which helps prevent or defend the systems from cyber-attacks. Distributed Ledger Technology like Blockchain with its various properties and advantages opens many opportunities for its use in the cyber-security domain and mitigating the associated risks. These technologies remove the need of any central trusted party or authority, which would facilitate recording and tracking of resources. This paper focuses on the use of Distributed Ledger Technology (DLT) in the field of Cyber-security. It focuses on the discussion of new distributed ledger technology IOTA, its features and working. This paper also focuses on one of the uses of the IOTA Tangle technology, which provides a solution for securing logs of a system. As the logs of a system are the most important evidence in the investigation phase of Cyber-Forensics, thus preserving the logs securely and maintaining their integrity is mandatory. Later in this paper, the use of IOTA is demonstrated for securing the logs of a system.
Smart contract helps to broaden the application of blockchain to various fields. In many cases, the non-blockchain systems (NBS) are involved. However, when a smart contract directly interacts with NBS, there is a non-deterministic issue (or a state conflict issue). The reason is that different nodes may obtain different statuses of NBS when the state changes in NBS. If we can solve this issue, a smart contract can be used to interact with current systems without an additional adaptor or bridge required by the existing solutions. In this paper, we regard the states of NBS as a sequence of states instead of a single state and propose to solve the non-deterministic issue by state synchronization. Blockchain nodes synchronize the state of the non-blockchain server via the P2P protocol. The state synchronization has requirements for both blockchain and NBS. For blockchain, it should provide the mechanism to synchronize states obtained from NBS. For NBS, it should sign the query result with a timestamp; the signature prevents the cheat of the observer (the blockchain), and the timestamp ensures the order of a state in the state sequence. At last, we show our verification results with respect to our proposed model and method.
Conventional certificate verification, whether paper-based or backed by a centralized digital registry, remains exposed to forgery, single points of failure, and slow manual cross-checking between issuers, holders, and verifiers. This paper presents a decentralized, blockchain-based framework for issuing, storing, and verifying academic and professional certificates that addresses these weaknesses without placing the full document on-chain. Each certificate is reduced to a SHA-256 hash, signed with the issuing institution's RSA private key, and recorded through an Ethereum smart contract, while the original file is retained off-chain on IPFS and referenced by its Content Identifier. Only institutions that pass a unanimous, vote-based onboarding process administered by a validator consortium are permitted to issue certificates, which constrains the system to a trusted-issuer model while preserving decentralization across the validator set. A hash-mapped Bloom Filter sits in front of the blockchain query path and performs a fast probabilistic existence check, allowing forged or non-existent certificates to be rejected before an on-chain lookup is triggered. A prototype was implemented with Solidity smart contracts on the Ethereum Sepolia testnet, a Node.js/Web3.js application layer, and a React.js frontend with MetaMask-based authentication. Evaluation on the testnet shows that the Bloom Filter pre-check lowers the average lookup time for invalid certificates by roughly 87%, keeps verification of valid certificates under two seconds end-to-end, holds the false-positive rate below 0.5% for up to 50,000 stored certificate hashes, and reduces the gas cost of issuing a certificate to approximately 4.57 USD. These results indicate that combining consortium governance, cryptographic hashing, and probabilistic filtering yields a certificate validation pipeline that is simultaneously tamper-resistant, low-cost, and fast enough for real-time institutional use.
With the development of information technology, big data has had a positive impact on the development of various industries. However, the continued growth of data has led to difficulties in data sharing. Blockchain, with its information sharing characteristics and decentralized management principles, is expected to become the new engine for building a future data sharing platform. Blockchain-based data sharing is useful for recording user transactions and sharing of multi-platform data. However, this technology not only has challenges in information storage, but also risks in third-party transactions. In this article, we propose a big data sharing and transaction framework based on blockchain. This framework uses the blockchain decentralization and openness idea to establish a big data transaction platform for multiple users. For the problem of distributed secure storage of big data in the blockchain, we propose a data-tamperproof mechanism that introduces a cryptographic algorithm to prevent transaction data from being tampered with during user storage. The purpose of this article is to ensure transaction security and data reliability when trading in the blockchain.
Chengjun Cai, Lei Xu, Anxin Zhou, Ruochen Wang · 6 authors
The rapid growth of Ethereum blockchain has brought extremely heavy overhead for coin owners or developers to bootstrap and access transactions on Ethereum. To address this, light client is enabled, which only stores a small fraction of blockchain data and relies on bootstrapped full nodes for transaction retrievals. However, because the retrieval requests are outsourced, it raises several severe concerns about the integrity of returned results and the leakage of sensitive blockchain access histories, largely hindering the wider adoption of this important lightweight design. In addition to security issues, the continuously increasing blockchain storage also urges for more effective query functionalities for the Ethereum blockchain, so as to enable more flexible and precise transaction retrievals.In this paper, we propose EncELC, a new Ethereum light client design that enforces full-fledged protections for clients and enables rich queries over the Ethereum blockchain. EncELC leverages trusted hardware (e.g., Intel SGX) as a starting point for building efficient yet secure processing, and further crafts several crucial performance and security refinement designs to boost query efficiency and conceal leakages inside and outside SGX enclave. We implement a prototype of EncELC and test its performance in several real settings, and the results have confirmed the practicality of EncELC.
Currently, technologies are developing very quickly and the need for information security is constantly increasing. In this connection, Blockchain technology is becoming in demand, which allows us to keep information safety and integrity. In addition, the technology enables the creation of a decentralized environment where transactions and data are take place without any third party organization. We proposed a decentralized web resource based on the Ethereum platform for managing student credits. The decentralized application (Dapp), will process, manage and control tokens, which represent credits that students gain for completed certain courses. The credit system is a first step towards a more transparent and technologically advanced form which could be used by universities and students to manage credits. The novelty of this scientific research is the creation of a web-based information resource based on Blockchain technology. Thanks to this resource, it becomes possible to track students' grades and receive reliable information about higher education. This completely eliminates the possibility of making changes to existing records.
Yanhong Xu, Reihaneh Safavi–Naini, Khoa Nguyen, Huaxiong Wang
Policy-based signatures (PBS) were proposed by Bellare and Fuchsbauer (PKC 2014) to allow an {\em authorized} member of an organization to sign a message on behalf of the organization. The user's authorization is determined by a policy managed by the organization's trusted authority, while the signature preserves the privacy of the organization's policy. Signing keys in PBS do not include user identity information and thus can be passed to others, violating the intention of employing PBS to restrict users' signing capability. In this paper, we introduce the notion of {\em traceability} for PBS by including user identity in the signing key such that the trusted authority will be able to open a suspicious signature and recover the signer's identity should the needs arise. We provide rigorous definitions and stringent security notions of traceable PBS (TPBS), capturing the properties of PBS suggested by Bellare-Fuchsbauer and resembling the "full traceability" requirement for group signatures put forward by Bellare-Micciancio-Warinschi (Eurocrypt 2003). As a proof of concept, we provide a modular construction of TPBS, based on a signature scheme, an encryption scheme and a zero-knowledge proof system. Furthermore, to demonstrate the feasibility of achieving TPBS from concrete, quantum-resistant assumptions, we give an instantiation based on lattices.
Jacob Swambo, Spencer Hommel, Bob McElrath, Bryan Bishop
A bitcoin covenant is a mechanism to enforce conditions on how the control of coins will be transferred in the future. This work introduces deleted-key covenants; using pre-signed transactions with secure key deletion. With this, a general class of covenants are possible without introducing new security risks to bitcoin. There is a range of security models for the key deletion process, but this is subject to a security-convenience trade-off and requires interactivity in a multi-party context. On the other hand, this work makes a compelling case for what can be gained through a soft-fork upgrade to the signature hash system [Dec17] which enables recovered-key covenants through elliptic curve key recovery. This has similar properties to script-based covenant mechanisms proposed previously [Rub20]. Key factors are discussed and compared for the three covenant mechanisms, including; the enforcement process, methods for proving accessibility of funds and whether or not they are bound by a covenant, methods for dynamic fee allocation, the underlying cryptographic assumptions, and their feasibility in single-party, hierarchical and adversarial multi-party contexts. Despite the relative downsides of deleted-key covenants, they are a practical tool for custody protocol design. The comparison shows precisely how soft-fork proposals improve the practicality of bitcoin covenants, through non-interactive enforcement and tighter cryptographic assumptions, to enhance custody protocols and enable some adversarial applications such as payment protocols.
Summary With the emergence of cloud storage security, how to ensure the security of cloud storage has become a research focus. The typical searchable encryption model consists of a single cloud service provider and has some unsolvable drawbacks. In this article, a new searchable encryption scheme in multi‐cloud was proposed based on blockchain. We first define a system model in multiple clouds and combine multiple cloud service providers to store data through a consortium chain. Then we store the encrypted documents and indexes in The Interplanetary File System (IPFS) and store the hash value and IPFS address of the documents in the blockchain. Our scheme can provide outsourced encrypted data retrieval based on multiple keywords, as well as verification schemes for the integrity of retrieved files. The theoretical analysis and experiments on real‐world data show the security and high performance of our scheme.
Since network storage services achieve widespread adoption, security and performance issues are becoming primary concerns, affecting the scalability of storage systems. Countermeasures like data auditing mechanisms and deduplication techniques are widely studied. However, the existing data auditing mechanism with deduplication cannot solve the problems such as high cost and reliance on trusted third parties in traditional approaches, and it also faces the problem of repeated auditing of data shared by multiple-tenant. This article proposes a blockchain-based deduplicatable data auditing mechanism. We first design a client-side data deduplication scheme based on bilinear-pair techniques to reduce the burden on users and service providers. On this basis, we achieve a trustworthy and efficient data auditing mechanism that helps to check data integrity by using both the blockchain technique and bilinear pairing cryptosystem. The blockchain system is used to record the behaviors of entities in both data outsourcing and auditing processes so that the corresponding immutable records can be used to not only ensure the credibility of audit results but also help to monitor unreliable third-party auditors. Finally, theoretical analysis and experiments reveal the effectiveness and performance of our scheme.
As the blockchain 2.0 platform, Ethereum's turing complete programming language and smart contract components make it play an important role in the commercialization of blockchain. With the further development of blockchain applications, the privacy and security issues of Ethereum have gradually emerged. To solve this problem, we proposed a blockchain privacy protection model called RZcash in the previous work. It implements the dynamically updateable and verifiable hiding of the asset information in Ethereum, namely the account balance and transaction amount. However, RZcash does not pay attention to the key redundancy problem that may be caused by the creation of secret accounts. In addition, the large size of proofs gives it high communication costs. In response to these problems, we further improve RZcash. For the key redundancy problem, we construct a new signature scheme based on the ciphertext equivalent test commitment. Moreover, we use the Schnorr signature and bulletproof to improve the corresponding proof scheme in RZcash, thereby reducing the size of proof. Based on these improvements, we propose a decentralized payment system, called RZcoin, based on Ethereum. Finally, we implement the algorithm model of RZcoin and evaluate its security and performance. The results show that RZcoin has higher security and Lower communication cost than RZcash.
Due to the unique characteristics of decentralization and security, blockchain is believed to have considerable potential to provide a wide range of benefits for ed-ucation development. Its application in education is relatively new but increasing very quickly. This paper introduced the typical blockchain techniques and charac-teristics briefly. Then, recent applications of blockchain in education were sum-marized comprehensively, especially those regarding learning record keeper, cer-tificate issue and management, and decentralized education ecosystem. Finally, technical and non-technical challenges were discussed. It is hoped to provide an in-depth look at the perspectives of blockchain in evolving education and help to the development of new application systems.