The increasing number of intelligent Machine-to-Machine Communication (M2M) devices in the end-user domain provide good resources for creating and sharing M2M application services. Therefore, transferring the role of a traditional centralized service provider to decentralized peers (end-users) acting as service providers is very promising. However, the future of decentralized M2M application services which are independently provided or consumed by several end-users in the M2M community depends on trust. Untrustworthy peers trying to deploy malfunctioning services for others mitigate the benefits of decentralized systems. Nowadays, the concept of distributed ledger and blockchain has an increased popularity regarding trustless computing among communities operating without centralized authorities. This research publication provides a comprehensive analysis and approach merging the concepts of M2M application services, trust and distributed ledger technologies. Moreover, this publication presents an optimized Trust Evaluation System which is used to ensure trustworthiness among peers in a M2M community. To improve the Trust Evaluation System the integration of blockchain for data storage is introduced. Additionally, blockchain technology is used to extend the existing trust model of the Trust Evaluation System to enable tamper-proof data and detection of untrustworthy peers. This publication reviews several existing approaches in the academic and industry sector to highlight the limitations of the blockchain regarding the consensus and proposes a novel Trust Consensus Protocol. This research publication also provides a practical evaluation of the proposed protocol.
This paper introduces FileTribe, a secure decentralized application for sharing files in closed groups. It employs IPFS, a distributed file system, as its data storage layer, avoiding the pitfalls of centralized storage solutions. Changes to files and group membership are recorded separately on a blockchain, making them irrefutable. A Decentralized Application (Dapp) on top of Ethereum is responsible for user authentication and reaching consensus among group members regarding the state of the group and shared files. File access control is supervised by the members themselves. These features combine to make FileTribe unique in its ability to serve a wide range of safetycritical scenarios, including ones where cloud-based or pure peerto- peer solutions fall short.
As the Internet of things (IoT) is increasingly popular, the number of IoT devices such as sensors and smart equipments are growing at an astonishing rate and data generated by these devices is exploding. However, these massive IoT data, stored in the form of isolated data centers, can not be shared by others who also need it. Moreover, data exchange is now needing a secure and fair mechanism to guarantee the data provider's rights and data security. Data providers also lack the motivation to share their data, as no effective mechanism exists to reward this behavior. To solve these problems, we propose a digital asset exchange mechanism based on blockchain technology, in which we record the behavior of data publishing and exchanging into the blockchain, which can ensure the reliability and transparency of data exchange without the restriction of trusted third-party payment institutions. Especially, to inspire the data providers to share their high-quality data, we design an incentive mechanism based on QoS, which gives higher rewards to those who provide high-quality data. Experimental results of this prototype demonstrate that this mechanism is appropriate to be applied in practice.
In Korea, a budget of tens of trillion won is put into the national R & D project every year [1]. Thanks to continuous technology and industrial development, Korea's ICT industry is gaining global attention. National R & D projects manage R & D projects in order of Planning - Evaluation - Management - Project results. In Korea, the R & D cycle process is diverse from the planning stage to the research results manager stage. In other words, we manage planning and evaluation by different departments and institutions. This type of management leads to problems such as redundant planning, insufficient sharing of research results, and duplicate submission. Currently, NTIS (National Technology Information Service) provides to address issues of redundancy and sharing. However, the NTIS's review of project redundancy is centered on keywords and does not provide information on the planning stage. This situation leads to redundant planning by ministries and closed management of research results. Therefore, we propose a platform that can easily share project planning information, review project redundancy, share research results, and check duplication of research results using block chain technology, which many experts and entrepreneurs refer to as future innovative technologies. In this paper, we propose a platform called Perfect Sharing Project Platform (PSPP). We describe that PSPP can achieve excellent research results through information sharing of project process. To support the perfect sharing, this platform uses a new notion of consensus algorithm, called POA (Proof of Atomicity). This platform is suitable for sharing information.
This paper deals with the security matters in automotive by using the Blockchain technology and an innovative thinking skill which has been applied to develop the new prototype design from the initial idea. The Blockchain Governance Game and Fog Computing are adopted to build the new highly secure decentralized service architecture. These relatively new technologies make possible to design the Blockchain based on the automotive security. Although the paper is condensed and does not contain the details, it will be the good guideline for the direction of future research. The thinking skill called Systematic Innovation is the core to solve this problems in the proper Blockchain security network design and well demonstrated in this paper.
It is common to certify when a file was created in digital investigations, e.g., determining first inventors for patentable ideas in intellectual property systems to resolve disputes. Secure time-stamping schemes can be derived from blockchain-based storage to protect files from backdating/forward-dating, where a file is integrated into a transaction on a blockchain and the timestamp of the corresponding block reflects the latest time the file was created. Nevertheless, blocks' timestamps in blockchains suffer from time errors, which causes the inaccuracy of files' timestamps. In this paper, we propose an accurate blockchain-based time-stamping scheme called Chronos. In Chronos, when a file is created, the file and a sufficient number of successive blocks that are latest confirmed on blockchain are integrated into a transaction. Due to chain quality, it is computationally infeasible to pre-compute these blocks. The time when the last block was chained to the blockchain serves as the earliest creation time of the file. The time when the block including the transaction was chained indicates the latest creation time of the file. Therefore, Chronos makes the file's creation time corresponding to this time interval. Based on chain growth, Chronos derives the time when these two blocks were chained from their heights on the blockchain, which ensures the accuracy of the file's timestamp. The security and performance of Chronos are demonstrated by a comprehensive evaluation.
Data security and privacy is one of the most crucial design parameter in any kind of modern application. The rate of connected devices is increasing day by day hence enhancing the security becomes a challenge. The healthcare industry faces many losses due to poor security design in data sharing and access management. Today most of the security is ensured leveraging cryptography alone, but blockchain has become another solution for security and privacy. Blockchain can be used as decentralized trust and a provider of universal truth across the application. Blockchain also utilizes cryptography in itself makes it more secure and trust able, hence the proposed solution uses combination of blockchain and cryptography to reinforce patient data permissions and sharing. Blockchain also enables to become compliant of various data protection and privacy rules.
Robert Norvill, Mathis Steichen, Wazen M. Shbair, Radu State
Know Your Customer (KYC) processes performed by banks on their customers are redundant, cumbersome and costly. Therefore, a system is proposed to automate menial tasks and allow sharing of data related to KYC. A blockchain dictates the collaboration between different participants and several services are built around it to support the functionality of the system as a whole. An access control system is used to share data legitimately.
We propose a blockchain-based reseller system that ensures the ownership of the products, prevents multiple selling, and guarantees the transfer of the ownership. The system employs mutual collateral method to prevent any dishonest behavior by both seller and buyer. This system is built on Ethereum blockchain to maintain the public record of transactions and uses ERC-721 tokens to define the traded goods. Sellers must confirm their identity with a valid MetaMask account and pay a first-time registration fee. The smart contract utilizes the OpenZeppelin library's Ownable. sol contract to implement the transfer of ownership securely. Users interact with the blockchain through a web interface that holds a MySQL database. In this paper, we present the system architecture, database schemas, operating sequence, sample code segments, and testing methods with an example of event ticket reselling. This system can create a secure, transparent, and trusted reselling service.
Ashar Ahmad, Muhammad Saad, Laurent Njilla, Charles Kamhoua · 6 authors
Blockchain-based audit trails provide a consensus-driven and tamper-proof trail of system events that are helpful in creating provenance in enterprise solutions. However, taking into account the transaction bulk generated by these applications and the throughput limitations of existing blockchains, a single ledger for record keeping can be inefficient and costly. To that end, we see an imperative need for a new blockchain design that is capable of addressing current challenges, without compromising security and provenance. Hence, we propose BlockTrail, a scalable and efficient blockchain solution for auditing applications. BlockTrail fragments the legacy blockchain systems into layers of co-dependent hierarchies, thereby reducing the time and space complexity, and increasing the throughput. BlockTrail is prototyped on "Practical Byzantine Fault Tolerance" (PBFT) protocol with a custom-built blockchain. Experiments with BlockTrail show that compared to the conventional schemes, BlockTrail is more efficient, and has less storage footprint.
William Pourmajidi, Lei Zhang, John Steinbacher, Tony Erwin · 5 authors
Logs contain critical information about the quality of the rendered services on the Cloud and can be used as digital evidence. Hence, we argue that the critical nature of logs calls for immutability and verification mechanism without the presence of a single trusted party. In this paper, we propose a blockchain-based log system, called Logchain, which can be integrated with existing private and public blockchains. To validate the mechanism, we create Logchain as a Service (LCaaS) by integrating it with Ethereum public blockchain network. We show that the solution is scalable (being able to process 100 log files per second) and fast (being able to "seal" a log file in 23 seconds, on average).
Outsourcing storage and computation to clouds is popular but also raises security concerns. Most existing solutions mainly focus on an honest-but-curious cloud server, while security designs against a malicious server have not drawn enough attention. Although there are a few works addressing the issue of verifiable designs that enable the data owner to verify the integrity of search results. Unfortunately, these verification schemes are not efficient and or applicable from one scenario to another. Motivated by this, in this paper, we propose a publicly verifiable search framework for outsourced encrypted data based on blockchain. In our framework, we store the encrypted index in a decentralized blockchain (Ethereum) while outsourcing the corresponding encrypted data to the cloud or Interplanetary File System (IPFS). Thus, once a user is authorized, he/she can get the query results and check the query integrity efficiently by the designed smart contract anytime without data owner being online. Besides, to guarantee the privacy of the data user in the Ethereum, we construct a stealth authorization scheme to achieve access authorization delivery. The security analysis and performance evaluation show that the proposed scheme is secure and practical for verification of encrypted data.
Recently there have been many emerging innovated Blockchain applications in various sectors including healthcare. In this paper, we propose a role-based access control system, namely, RBAC-HDE, which harnesses the powerful features of Blockchain such as immutability and decentralization, in order to facilitate secure data exchange for healthcare. We design and implement an Ethereum-based testbed to demonstrate the basic idea. Our preliminary results have shown the feasibility and potential of this approach.
Michał Król, Alberto Sonnino, Mustafa Al-Bassam, Argyrios G. Tasiopoulos · 6 authors
As cryptographic tokens and altcoins are increasingly being built to serve as utility tokens, the notion of useful work consensus protocols is becoming ever more important. With useful work consensus protocols, users get rewards after they have carried out some specific tasks useful for the network. While in some cases the proof of some utility or service can be provided, the majority of tasks are impossible to verify reliably. To deal with such cases, we design “Proof-of-Prestige” (PoP)—a reward system that can run directly on Proof-of-Stake (PoS) blockchains or as a smart contract on top of Proof-of-Work (PoW) blockchains. PoP introduces “prestige,” which is a volatile resource that, in contrast to coins, regenerates over time. Prestige can be gained by performing useful work, spent when benefiting from services, and directly translates to users minting power. Our scheme allows us to reliably reward decentralized workers while keeping the system free for the end-users. PoP is resistant against Sybil and collusion attacks and can be used with a vast range of unverifiable tasks. We build a simulator to assess the cryptoeconomic behavior of the system and deploy a full prototype of a content dissemination platform rewarding its participants. We implement the blockchain component on both Ethereum (PoW) and Cosmos (PoS), provide a mobile application, and connect it with our scheme with a negligible memory footprint. Finally, we adapt a fair exchange protocol allowing us to atomically exchange files for rewards also in scenarios where not all the parties have Internet connectivity. Our evaluation shows that even for large Ethereum traces, PoP introduces sub-millisecond computational overhead for miners in Cosmos and less than 0.013$ smart contract invocation cost for users in Ethereum.
Thomas Kerber, Aggelos Kiayias, Markulf Kohlweiss, Vassilis Zikas
We present Ouroboros Crypsinous, the first formally analyzed privacy-preserving proof-of-stake blockchain protocol. To model its security we give a thorough treatment of private ledgers in the (G)UC setting that might be of independent interest. To prove our protocol secure against adaptive attacks, we introduce a new coin evolution technique relying on SNARKs and key-private forward secure encryption. The latter primitive-and the associated construction-can be of independent interest. We stress that existing approaches to private blockchain, such as the proof-of-work-based Zerocash are analyzed only against static corruptions.
Building trustless cross-blockchain trading protocols is challenging. Centralized exchanges thus remain the preferred route to execute transfers across blockchains. However, these services require trust and therefore undermine the very nature of the blockchains on which they operate. To overcome this, several decentralized exchanges have recently emerged which offer support for atomic cross-chain swaps (ACCS). ACCS enable the trustless exchange of cryptocurrencies across blockchains, and are the only known mechanism to do so. However, ACCS suffer significant limitations; they are slow, inefficient and costly, meaning that they are rarely used in practice. We present XCLAIM: the first generic framework for achieving trustless and efficient cross-chain exchanges using cryptocurrency-backed assets (CbAs). XCLAIM offers protocols for issuing, transferring, swapping and redeeming CbAs securely in a non-interactive manner on existing blockchains. We instantiate XCLAIM between Bitcoin and Ethereum and evaluate our implementation; it costs less than USD 0.50 to issue an arbitrary amount of Bitcoin-backed tokens on Ethereum. We show XCLAIM is not only faster, but also significantly cheaper than atomic cross-chain swaps. Finally, XCLAIM is compatible with the majority of existing blockchains without modification, and enables several novel cryptocurrency applications, such as cross-chain payment channels and efficient multi-party swaps.
During the course of education the students achieve many certificates. Student produce these certificates while applying for jobs at public or private sectors, where all these certificates are needed to be verified manually. There can be incidents where students may produce the fake certificate and it is difficult to identify them. This problem of fake academic certificates has been a longstanding issue in the academic community. Because it is possible to create such certificates at low cost and the process to verify them is very complex, as they are manually needed to be verified. This problem can be solved by storing the digital certificates on the Blockchain. The Blockchain technology provides immutability and publicly verifiable transactions, these properties of Blockchain can be used to generate the digital certificate which are anti-counterfeit and easy to verify.
Data owners upload large files to cloud storage servers, but malicious servers may potentially tamper data. To check integrity of remote data, Proof-of-retrievability (PoR) schemes were introduced. Existing PoR protocols assume that data owners and third-party auditors are honest and audit only the potentially malicious cloud server to check integrity of stored data. In this article, we consider a system where any party may attempt to cheat others and consider collusion cases. We design a protocol, Cumulus, that is secure under such adversarial assumptions and use blockchain smart contracts to act as mediator in case of dispute and payment settlement. We use state channels to reduce blockchain interactions in order to build a practical audit solution. The security of the protocol has been proven in Universal Composability (UC) framework. Finally, we illustrate several applications of our basic protocol and evaluate practicality of our approach via a prototype implementation for fairly selling large files over the Ethereum platform. We evaluate the prototype and show that our scheme has comparable performance.
Data owners upload large files to cloud storage servers, but malicious servers may potentially tamper data. To check integrity of remote data, Proof of Retrievability (PoR) schemes were introduced. Existing PoR protocols assume that data owners and third-party auditors are honest and audit only the potentially malicious cloud server to check integrity of stored data. In this paper we consider a system where any party may attempt to cheat others and consider collusion cases. We design a protocol that is secure under such adversarial assumptions and use blockchain smart contracts to act as mediator in case of dispute and payment settlement. We use state channels to reduce blockchain interactions in order to build a practical audit solution. We implement and evaluate a prototype using Ethereum as the blockchain platform and show that our scheme has comparable performance.
Recent advancements in information and communication technology is enabling a significant revolution in e-Health research and industry. In the case of personal medical data sharing, data security and convenience are crucial requirements to the interaction and collaboration of electronic medical record (EMR) systems. However, it’s hard for current systems to meet these requirements as they have inconsistent structures in terms of security policies and access control models. A new solution direction is essential to enhance data-accessing while regulating it with government mandates in privacy and security to ensure the accountability of the medical usage data. Blockchain seems to pave the way for revolution in the conventional healthcare industry benefiting by its unique features such as data privacy and transparency. In this paper, a blockchain-based medical platform using a smart contract is proposed to secure the EMR management. This approach provides patients a comprehensive, immutable log and easy access to their medical information across different departments within the hospital. A case study for hospital is built on a permissioned network, and a series of experimental tests are performed to demonstrate the usability and efficiency of the designed platform. Lastly, a benchmark study by leveraging various performance metrics is made and the outcomes indicate that the designed platform surpasses the ability of existing works in various aspects. The results of this work reveal that the proposed solution has the great potential to accelerate the development of a decentralized digital healthcare ecosystem.
Mohamed El Ghazouani, Moulay Ahmed El Kiram, Latifa Er-Rajy
Recently, data storage represents one of the most important services in Cloud Computing. The cloud provider should ensure two major requirements which are data integrity and storage efficiency. Blockchain data structure and the efficient data deduplication represent possible solutions to address these exigencies. Several approaches have been proposed, some of them implement deduplication in Cloud server side, which involves a lot of computation to eliminate the redundant data and it becomes more and more complex. Therefore, this paper proposed an efficient, reliable and secure approach, in which the authors propose a Multi-Agent System in order to manipulate deduplication technique that permits to reduce data volumes thereby reduce storage overhead. On the other side, the loss of physical control over data introduces security challenges such as data loss, data tampering and data modification. To solve similar problems, the authors also propose Blockchain as a database for storing metadata of client files. This database serves as logging database that ensures data integrity auditing function.