Md Zakirul Alam Bhuiyan, Aliuz Zaman, Tian Wang, Guojun Wang · 6 authors
The increase in reported incidents of security breaches that compromise privacy of individuals requires us to question the current model used to collect patient information. What we have learned from bitcoin and the underlying blockchain technology is that there are ways for us to protect this information by using a distributed ledger. In this paper, we review and propose a solution that can be used to manage individual health data as well as cross-institutional sharing of this information. The solution will increase clinical effectiveness and an increase in research when the data is shared with researchers. The proposed system solution based on blockchain technology that includes providers, hospitals and clinic, insurance companies, and patients. All along the ownership of the data would belong to the individual or the patient. In the solution, we suggest to adopt a private blockchain solution where all participants are known and trusted, which allows for privacy and security of the data.
We propose a bitcoin generalization as a solution to the problem of scalability. The block is redefined as a sequence of sub-blocks of increasing sizes that coexist as different levels of compromise between decentralization and transactions throughput. Miners and users can decide individually the sizes they use without affecting others in the network.
This review focuses on the evolution of cloud computing and distributed ledger technologies (blockchains) over the last decade. Cloud computing relies mainly on a conceptually centralized service provisioning model, while blockchain technologies originate from a peer-to-peer and a completely distributed approach. Still, noteworthy commonalities between both approaches are often overlooked by researchers. Therefore, to the best of the authors knowledge, this paper reviews both domains in parallel for the first time. We conclude that both approaches have advantages and disadvantages. The advantages of centralized service provisioning approaches are often the disadvantages of distributed ledger approaches and vice versa. It is obviously an interesting question whether both approaches could be combined in a way that the advantages can be added while the disadvantages could be avoided. We derive a software stack that could build the foundation unifying the best of these two worlds and that would avoid existing shortcomings like vendor lock-in, some security problems, and inherent platform dependencies.
The DFINITY blockchain computer provides a secure, performant and flexible consensus mechanism. At its core, DFINITY contains a decentralized randomness beacon which acts as a verifiable random function (VRF) that produces a stream of outputs over time. The novel technique behind the beacon relies on the existence of a unique-deterministic, non-interactive, DKG-friendly threshold signatures scheme. The only known examples of such a scheme are pairing-based and derived from BLS. The DFINITY blockchain is layered on top of the DFINITY beacon and uses the beacon as its source of randomness for leader selection and leader ranking. A "weight" is attributed to a chain based on the ranks of the leaders who propose the blocks in the chain, and that weight is used to select between competing chains. The DFINITY blockchain is layered on top of the DFINITY beacon and uses the beacon as its source of randomness for leader selection and leader ranking blockchain is further hardened by a notarization process which dramatically improves the time to finality and eliminates the nothing-at-stake and selfish mining attacks. DFINITY consensus algorithm is made to scale through continuous quorum selections driven by the random beacon. In practice, DFINITY achieves block times of a few seconds and transaction finality after only two confirmations. The system gracefully handles temporary losses of network synchrony including network splits, while it is provably secure under synchrony.
The prevalence of IoT devices makes them an ideal target for attackers. To\nreduce the risk of attacks vendors routinely deliver security updates (patches)\nfor their devices. The delivery of security updates becomes challenging due to\nthe issue of scalability as the number of devices may grow much quicker than\nvendors' distribution systems. Previous studies have suggested a permissionless\nand decentralized blockchain-based network in which nodes can host and deliver\nsecurity updates, thus the addition of new nodes scales out the network.\nHowever, these studies do not provide an incentive for nodes to join the\nnetwork, making it unlikely for nodes to freely contribute their hosting space,\nbandwidth, and computation resources. In this paper, we propose a novel\ndecentralized IoT software update delivery network in which participating nodes\nreferred to as distributors) are compensated by vendors with digital currency\nfor delivering updates to devices. Upon the release of a new security update, a\nvendor will make a commitment to provide digital currency to distributors that\ndeliver the update; the commitment will be made with the use of smart\ncontracts, and hence will be public, binding, and irreversible. The smart\ncontract promises compensation to any distributor that provides\nproof-of-distribution, which is unforgeable proof that a single update was\ndelivered to a single device. A distributor acquires the proof-of-distribution\nby exchanging a security update for a device signature using the Zero-Knowledge\nContingent Payment (ZKCP) trustless data exchange protocol. Eliminating the\nneed for trust between the security update distributor and the security\nconsumer (IoT device) by providing fair compensation, can significantly\nincrease the number of distributors, thus facilitating rapid scale out.\n
Alexandre Bovet, Carlo Campajola, Jorge F. Lazo, Francesco Mottes · 10 authors
The functioning of the cryptocurrency Bitcoin relies on the open availability of the entire history of its transactions. This makes it a particularly interesting socio-economic system to analyse from the point of view of network science. Here we analyse the evolution of the network of Bitcoin transactions between users. We achieve this by using the complete transaction history from December 5th 2011 to December 23rd 2013. This period includes three bubbles experienced by the Bitcoin price. In particular, we focus on the global and local structural properties of the user network and their variation in relation to the different period of price surge and decline. By analysing the temporal variation of the heterogeneity of the connectivity patterns we gain insights on the different mechanisms that take place during bubbles, and find that hubs (i.e., the most connected nodes) had a fundamental role in triggering the burst of the second bubble. Finally, we examine the local topological structures of interactions between users, we discover that the relative frequency of triadic interactions experiences a strong change before, during and after a bubble, and suggest that the importance of the hubs grows during the bubble. These results provide further evidence that the behaviour of the hubs during bubbles significantly increases the systemic risk of the Bitcoin network, and discuss the implications on public policy interventions.
We present IPchain, a blockchain to store the allocations and delegations of IP addresses, with the aim of easing the deployment of secure interdomain routing systems. Interdomain routing security is of vital importance to the Internet since it prevents unwanted traffic redirections. IPchain makes use of blockchains' properties to provide flexible trust models and simplified management when compared to existing systems. In this paper we argue that Proof of Stake is a suitable consensus algorithm for IPchain due to the unique incentive structure of this use-case. We have implemented and evaluated IPchain's performance and scalability storing around 150k IP prefixes in a 1GB chain.
Andrei Yu. Khrennikov, Sergei V. Kozyrev, W. A. Zúñiga-Galindo
Introduction The connections between the Archimedean heat equations with number theory and geometry are well known and deep. Let us mention here the connection with the Riemann zeta function which leads naturally to trace-type formulae, see e.g. [48] and the references therein, and the connection with the Atiyah–Singer index theorem, see e.g. [178] and the references therein. The study of non-Archimedean counterparts of the above-mentioned matters is quite relevant, especially taking into account that the Connes and Deninger programs to attack the Riemann hypothesis lead naturally to these matters, see e.g. [112], [121], [309] and the references therein. For instance, several types of p -adic trace formula have been studied, see e.g. [13], [96], [449] and the references therein. In this chapter we study heat traces and spectral zeta functions attached to certain p -adic Laplacians, denoted as A β , following [105]. Using an approach inspired by the work of Minakshisundaram and Pleijel, see [340]–[342], we find a formula for the trace of the semigroup e − tAβ acting on the space of square integrable functions supported on the unit ball with average zero, see Theorem 12.13. The trace of e − t A β is a p -adic oscillatory integral of Laplace–type. We do not know the exact asymptotics of this integral as t tends to infinity; however, we can obtain a good estimation for its behavior at infinity, see Theorem 12.13 (ii). Several unexpected mathematical situations occur in the p -adic setting. For instance, the spectral zeta functions are p -adic Igusa-type integrals, see Theorem 12.18. The p -adic spectral zeta functions studied here may have infinitely many poles on the boundary of their domain of holomorphy. Thus, to the best of our knowledge, the standard Ikehara Tauberian theorems cannot be applied to obtain the asymptotic behavior for the function encompassing the eigenvalues of A β less than or equal to T ≥ 0. However, we are still able to find good estimates for this function, see Theorem 12.18, Remark 12.19, and Conjecture 12.20. The proofs require several results on certain “boundary-value problems” attached to p -adic heat equations associated with operators A β , see Proposition 12.5, Theorem 12.11, and Proposition 12.12.
The advent of smart contracts presents several problems for the traditional law of contract. One of the most pressing issues is how the forensic process of interpretation needs to change in order to accommodate contracts written in computer code. Not only is the language of smart contracts unlike the human languages with which courts are used to dealing, but its logical architecture also differs. This means that enlisting the services of an expert to provide a literal translation for a judge to interpret is unlikely to be helpful. The development of a “reasonable coder” test would seem to be a viable means of proceeding. The self-executing nature of smart contracts means that, in the case of executory agreements, rectification may well become a more widely-used remedy.
This paper presents Conflux, a fast, scalable and decentralized blockchain system that optimistically process concurrent blocks without discarding any as forks. The Conflux consensus protocol represents relationships between blocks as a direct acyclic graph and achieves consensus on a total order of the blocks. Conflux then, from the block order, deterministically derives a transaction total order as the blockchain ledger. We evaluated Conflux on Amazon EC2 clusters with up to 20k full nodes. Conflux achieves a transaction throughput of 5.76GB/h while confirming transactions in 4.5-7.4 minutes. The throughput is equivalent to 6400 transactions per second for typical Bitcoin transactions. Our results also indicate that when running Conflux, the consensus protocol is no longer the throughput bottleneck. The bottleneck is instead at the processing capability of individual nodes.
A new legal field is emerging around blockchain platforms and automated transactions. Understanding the relationships between law, legal enforcement, and these technological systems has become critical for scaling blockchain applications. Because ‘smart contracts’ do not themselves constitute agreements, the first necessary ‘legal’ development for transacting with these technologies involves linking computational transactions to natural language contracts. Various groups have accordingly begun building libraries of machine readable transaction modules that correspond to natural language contracting elements. In doing so, they are creating the building blocks for ever more complex transactions that will ultimately define the entire envelope of computational legal conduct in these environments, and likely standardise the field. However, also critical to emerging blockchain ‘legalities’, is the capacity for dispute resolution and legal enforcement. Beyond the performance of parties, or the quality of goods and services transacted, new mechanisms are also needed to address the performance of the computational transaction systems themselves. These are necessary to address the reality that smart contracts cannot be forced to perform actions beyond the parameters of their coding, even by a judicial order. Legal tools, both technological and institutional, are thus being developed to ‘soften’ the effects of self-executing transactions. In this article we treat these developments as law-making practices that are constitutive of an emerging legal field. Legal engineering exercises of this kind are not novel, and by drawing on historic examples from the common law and international arbitration, we gain insights into the competitive dynamics likely to be shaping legal engagements on the blockchain.
As Byzantine Agreement (BA) protocols find application in large-scale decentralized cryptocurrencies, an increasingly important problem is to design BA protocols with improved communication complexity. A few existing works have shown how to achieve subquadratic BA under an {\it adaptive} adversary. Intriguingly, they all make a common relaxation about the adaptivity of the attacker, that is, if an honest node sends a message and then gets corrupted in some round, the adversary {\it cannot erase the message that was already sent} --- henceforth we say that such an adversary cannot perform "after-the-fact removal". By contrast, many (super-)quadratic BA protocols in the literature can tolerate after-the-fact removal. In this paper, we first prove that disallowing after-the-fact removal is necessary for achieving subquadratic-communication BA. Next, we show new subquadratic binary BA constructions (of course, assuming no after-the-fact removal) that achieves near-optimal resilience and expected constant rounds under standard cryptographic assumptions and a public-key infrastructure (PKI) in both synchronous and partially synchronous settings. In comparison, all known subquadratic protocols make additional strong assumptions such as random oracles or the ability of honest nodes to erase secrets from memory, and even with these strong assumptions, no prior work can achieve the above properties. Lastly, we show that some setup assumption is necessary for achieving subquadratic multicast-based BA.
Gabriel Kamau, Caroline Boore, Elizaphan Maina, Stephen Njenga
The burden of disease is higher by far in developing countries than in the developed world. Developing countries today are turning to technology as the silver bullet or remedy. Indeed, Information and Communication Technology has turned into a key-enabling tool in the enhanced healthcare management. The electronic health records or electronic medical records (EMR) a key component of medical informatics symbolize potential solutions for enhanced healthcare. However, interoperability and security of EMR systems has been the two main challenges of EMR in the healthcare industry. By analyzing existing literature using scoping review research approach this paper explored the potential use of blockchain technology in improving the interoperability and security of EMR systems for the benefit of different stakeholders in health sector in developing countries such as Kenya. To achieve our main objective, five databases were searched and 204 papers screened for inclusion. As a result of the search and screen process, we identified 25 relevant articles.
James R. Maddison, Dr Jared Robert Keller, Jamie Fawcett, Caley Dewhurst · 8 authors
Part 1: Smart contracts and uses for business 7Blockchains, distributed ledgers and trust 8Key properties of distributed ledgers 8Part 1: Are smart contracts useful for me and my business?The original blockchain was designed to enable financial transactions without the need for any trusted third party.The design of the system relies on storing records of all transactions on a new kind of database, with a unique set of properties, that engender trust between members of the network in those transactions.In particular, this trust resides in the distributed nature of the database -with every member of the peer network having a copy of the blockchain and equal authority to add to it.With no central copy, every member of the network, or node, can add to the database, though they must reach consensus before doing so -a process typically handled through the use of cryptography and economic incentive.Blockchain databases can be public, so anyone can join, or can have restricted permissions to read or write to the database, depending on the design chosen.Distributed ledgers such as these can arguably underpin trusted exchange of cryptocurrencies or other financial assets in the absence of trusted third parties rather effectively.However, many people are excited by their potential application to other use cases -typically using the immutable and distributed nature of the database to create a verifiable, single, trusted record of particular events.This can open up the possibility of answering some of the challenges that cannot be solved with a centralised database -primarily because businesses would no longer need to trust a single third party to operate the system or database.Examples of how distributed ledgers could be applied include creating a single register for art and collectibles (Codex protocol), guaranteeing the integrity of digital archives (ARCHANGEL) or managing digital music rights (Blokur).When asked to identify the most promising use cases for distributed ledgers and smart contracts, many of the people we spoke to immediately reached for the Open Data Institute 2018 / Technical report How can smart contracts be useful for businesses? 3Open Data Institute 2018 / Technical report How can smart contracts be useful for businesses? 4iii) Identify how the system will be funded and governed, and how value will be transferredAll technology systems and business processes create setup and operational costs.How these costs are administered and by whom will have a big impact on not only trust in the system but incentive to participate.Businesses need to make decisions about the extent to which they can use the technology and the extent to which they can use existing industry mechanisms to tackle these three challenges.In this choice between idealism and pragmatism is the implicit challenge of designing solutions that fit the needs of the business and the industry without losing all the potential benefits of this technological approach.Such a balance is difficult, and businesses need to be mindful about the different approaches that can be taken.Given the reliance on industry context, many systems will require different approaches in response to different challenges, and often these will be a mixture of the ideal and pragmatic. Key takeawaysDaily interactions between people, businesses, and other organisations are all underpinned by trust.Distributed ledgers are an emerging set of database technologies that have the potential to play a part in informing this trust -using their unique properties of immutability and distributed maintenance to create a verifiable, single, trusted record of particular events.Smart contracts are pieces of executable computer code stored on a distributed ledger that, when certain conditions are met, can automatically modify data on that ledger -potentially providing the means to automate different processes within the database.Distributed ledgers and smart contracts are potentially useful for businesses but only if there is a clearly defined use case where there is lack of trust between multiple actors and no central authority is trusted to administer the entire system.Having identified a clear use case, businesses looking to implement distributed ledger and smart contract approaches to tackle challenges need to remain pragmatic about the capabilities of the technology and the existing industry context.Specifically, businesses should be prepared to make decisions about: i) how to get data into the ledger in a trustworthy manner ii) how to handle edge cases and resolve disputes iii) how to fund, govern and administer the system effectively Open Data Institute 2018 / Technical report How can smart contracts be useful for businesses? 5 Open Data Institute 2018 / Technical report How can smart contracts be useful for businesses?6 3 technologies that store data, it is important to understand what role blockchains and distributed ledgers might play in creating a robust data infrastructure. 1Geofrey T Mills (1994), 'Early Accounting in Northern Italy: The Role of Commercial Development and the Printing Press in the Expansion of Double-Entry From Genoa, Florence, and Venice', http://www.accountingin.com/accounting-historians-journal/volume-21-number-1/ear ly-accounting-in-northern-italy-the-role-of-commercial-development
In this work, we present a low-latency partition tolerant distributed ledger using a novel directed acyclic graph (DAG) structure. By forcing information to be published at specific deterministic locations, we avoid complex consensus algorithms and eliminate confirmation periods. We implement our DAG over a fully decentralized overlay network, leveraging BitTorrent concepts for peer-to-peer (P2P) rendezvous and block propagation. We compute overall expected latency using Erd¨os-R´enyi random graph models and present initial proof-of-concept software. The resulting work will allow anyone to create fully decentralized services (records, databases, etc.) resistant to attack, manipulation, and censorship.
Blockchain is a novel technology that is rising a lot of interest in the industrial and re- search sectors because its properties of decentralisation, immutability and data integrity. Initially, the underlying consensus mechanism has been designed for permissionless block- chain on trustless network model through the proof-of-work, i.e. a mathematical challenge which requires high computational power. This solution suffers of poor performances, hence alternative consensus algorithms as the proof-of-stake have been proposed. Conversely, for permissioned blockchain, where participants are known and authenti- cated, variants of distributed consensus algorithms have been employed. However, most of them comes out without formal expression of security analysis and trust assumptions because the absence of an established knowledge. Therefore the lack of adequate analysis on these algorithms hinders any cautious evaluation of their effectiveness in a real-world setting where systems are deployed over trustless networks, i.e. Internet ...
Konstantin Danilov, Ruslan Rezin, Alexander Kolotov, Ilya Afanasyev
The decentralized trading market approach, where both autonomous agents and people can consume and produce services expanding own opportunities to reach goals, looks very promising as a part of the Fourth Industrial revolution. The key component of the approach is a blockchain platform that allows an interaction between agents via liability smart contracts. Reliability of a service provider is usually determined by a reputation model. However, this solution only warns future customers about an extent of trust to the service provider in case it could not execute any previous liabilities correctly. From the other hand a blockchain consensus protocol can additionally include a validation procedure that detects incorrect liability executions in order to suspend payment transactions to questionable service providers. The paper presents the validation methodology of a liability execution for agent-based service providers in a decentralized trading market, using the Model Checking method based on the mathematical model of finite state automata and Temporal Logic properties of interest. To demonstrate this concept, we implemented the methodology in the Duckietown application, moving an autonomous mobile robot to achieve a mission goal with the following behavior validation at the end of a completed scenario.
Recently, the notion of cryptocurrencies has come to the fore of public interest. These assets that exist only in electronic form, with no underlying value, offer the owners some protection from tracking or seizure by government or creditors. We model these assets from the perspective of asset flow equations developed by Caginalp and Balenovich, and investigate their stability under various parameters, as classical finance methodology is inapplicable. By utilizing the concept of liquidity price and analyzing stability of the resulting system of ordinary differential equations, we obtain conditions under which the system is linearly stable. We find that trend-based motivations and additional liquidity arising from an uptrend are destabilizing forces, while anchoring through value assumed to be fairly recent price history tends to be stabilizing.
Cyber-physical systems (CPS), robotics, Internet of Things, information and communication technologies have become more and more popular over the last several years. These topics open new perspectives and scenarios that can automate processes in human life. CPS are aimed at interaction support in information space for physical entities communicated in physical space in real time. At the same time the blockchain technology that becomes popular last years allows to organize immutable distributed database that store all significant information and provide access for CPS participants. The paper proposes an approach that is based on ontology-based context management, publish/subscribe semantic interoperability support, and blockchain techniques. Utilization of these techniques provide possibilities to develop CPS that supports dynamic, distributed, and stable coalition formation of the resources. The case study presented has been implemented for the scenario of heterogeneous mobile robots’ collaboration for the overcoming of obstacles. There are two types of robots and an information service participating in the scenario. Evaluation shows that the proposed approach is applicable for the presented class of scenarios.
The traditional way of tracking food quality through the supply chain can be a difficult task. The most essential issue is food contamination. It often takes weeks even months to identify when and where a food product was contaminated. Another critical point is complex overlapping distribution and processing ecosystem involving farms, distributors, retailers and consumers, which makes it difficult to assure food provenance. Our SafeFood solution using blockchain and Internet of Things technologies can quickly track a food product's process from farm to storage shelf. In the context of food supply, a blockchain could be used to keep track and history of every single item processed throughout the supply chain. With the Hyperledger Fabric, all the food information is collected into the blockchain throughout every step in the supply chain to offer a more efficient way to figure out when and where food items were contaminated, which can help producers the limited contagions by public health officials . The benefits of more transparent food supply chain include: (1) increase the trust multiplied by each participant in food supply chain; (2) identify the source of compromised food and reduce the unnecessarily broad recall, (3) improve the co-ordination in food supply chain; (4) increase operation efficiency; (5) provide better food safety, more freshness and avoid food fraud for customer.
BACKGROUND A blockchain is a digitized, decentralized, distributed public ledger that acts as a shared and synchronized database that records cryptocurrency transactions. Despite the shift toward digital platforms enabled by electronic medical records, demonstrating a will to reform the health care sector, health systems face issues including security, interoperability, data fragmentation, timely access to patient data, and silos. The application of health care blockchains could enable data interoperability, enhancement of precision medicine, and reduction in prescription frauds through implementing novel methods in access and patient consent. OBJECTIVE To summarize the evidence on the strategies and frameworks utilized to implement blockchains for patient data in health care to ensure privacy and improve interoperability and scalability. It is anticipated this review will assist in the development of recommendations that will assist key stakeholders in health care blockchain implementation, and we predict that the evidence generated will challenge the health care status quo, moving away from more traditional approaches and facilitating decision making of patients, health care providers, and researchers. METHODS A systematic search of MEDLINE/PubMed, Embase, Scopus, ProQuest Technology Collection and Engineering Index will be conducted. Two experienced independent reviewers will conduct titles and abstract screening followed by full-text reading to determine study eligibility. Data will then be extracted onto data extraction forms before using the Cochrane Collaboration Risk of Bias Tool to appraise the quality of included randomized studies and the Risk of Bias in nonrandomized studies of Interventions to assess the quality of nonrandomized studies. Data will then be analyzed and synthesized. RESULTS Database searches will be initiated in September 2018. We expect to complete the review in January 2019. CONCLUSIONS This review will summarize the strategies and frameworks used to implement blockchains in health care to increase data privacy, interoperability, and scalability. This review will also help clarify if the strategies and frameworks required for the operationalization of blockchains in health care ensure the privacy of patient data while enabling efficiency, interoperability, and scalability.