Abstract

1. Introduction

2. Overview of blockchain history

3. Blockchain Technology

4. Blockchain Applications

5. Security risks and attacks with blockchain

6. Security measures for blockchain

7. Challenges and research trends

8. Related work

9. Conclusion

Conflict of interest

References

Abstract

     Blockchain is a technology that has desirable features of decentralization, autonomy, integrity, immutability, verification, fault-tolerance, anonymity, auditability, and transparency. In this paper, we first carry out a deeper survey about blockchain technology, especially its history, consensus algorithms’ quantitative comparisons, details of cryptography in terms of public key cryptography, Zero-Knowledge Proofs, and hash functions used in the blockchain, and the comprehensive list of blockchain applications. Further, the security of blockchain itself is a focus in this paper. In particular, we assess the blockchain security from risk analysis to derive comprehensive blockchain security risk categories, analyze the real attacks and bugs against blockchain, and summarize the recently developed security measures on blockchain. Finally, the challenges and research trends are presented to achieve more scalable and securer blockchain systems for the massive deployments.

Introduction

     In blockchain, data are kept in a distributed ledger. It is the blockchain technology to provide integrity and availability that allows participants in the blockchain network to write, read, and verify transactions recorded in a distributed ledger. However, it does not allow the deletion and modification operations on the transactions and other information stored on its ledger. The blockchain system is supported and secured by cryptographic primitives and protocols, e.g., digital signatures, hash functions, etc. These primitives guarantee the transactions that are recorded into the ledger are integrity-protected, authenticity-verified, and non-repudiated. Further, as a distributed network, to allow the entire set of participants to agree on a unified record, the blockchain technology also needs a consensus protocol, which is essentially a set of rules to be followed by every participant, in order to achieve a globally unified view.

     In a trustless environment, blockchain provides users with desirable features of decentralization, autonomy, integrity, immutability, verification, fault-tolerance, attracted great academic and industrial attention in the recent few years, anonymity, auditability, and transparency [[1], [2], [3]]. With these advanced features, blockchain technology has attracted great academic and industrial attention in the recent few years.

Conclusion

     This paper has first conducted a deeper survey on blockchain technology in terms of overview, consensus algorithms, smart contracts, and cryptography for blockchain. It presented the history of blockchain, and compared the five most common consensus algorithms and one most different consensus algorithm in as much detail and quantitative as possible. Public key cryptography, Zero-Knowledge Proof, and hash functions used in blockchain have been described in detail for integrity, authentication, nonrepudiation, and payment address required in blockchain systems. This paper has then listed the comprehensive applications of blockchain. It has further presented the rich information and comparisons of eight cryptocurrencies as the first blockchain application, supply chain as a widely used case, and Smart Dubai Office as the first whole government service application. Further, the security of blockchain itself is a focus in this paper. It has described the comprehensive security risks categories based on the Top 10 Web Application Security Risks, low level risks, and high level risks. It has surveyed many real attacks and bugs on blockchain systems and listed out their root causes. The paper has then presented the security measures in the areas of security analysis, detecting malicious codes & bugs, software codes security, privacy preserving, and so on. Specially, it has presented and compared eleven smart contract bytecode vulnerability analysis tools. Finally, the challenges and research trends have been presented to build more scalable and securer blockchain systems for massive deployments.

Abstract

Document Sections

I. Introduction (heading 1)

II. Basic Technology of Blockchain

III. Blockchain Technology Architecture

IV. The Applications of Blockchain

V. Challenges and Future Trends

VI. Discussion and Future Directions

Abstract:

Starting from the basic concept of blockchain technology, the paper introduces the architecture of blockchain technology and the typical application of blockchain technology, and finally summarizes the challenges faced by blockchain technology, so as to provide some reference for the technological path innovation and data value reconstruction of deep integration of blockchain technology and various fields.

I. INTRODUCTION (HEADING 1)

Blockchain Technology (BT) is a new decentralized infrastructure and distributed computing paradigm, which uses encrypted chained data blocks to verify and store data, uses distributed node consensus algorithm to generate and update data, and uses smart contract to program and operate data. Its outstanding feature is that it doesn’t rely on the third-party trusted organization to realize the value communication between nodes without trust relationship.

Blockchain is a novel type of distributed infrastructure and computing paradigm that integrates technologies including distributed data storage, peer-to-peer (P2P) transmission, consensus algorithm, and cryptography [1]. It uses block-chain data structures to store and verify data, uses distributed consensus algorithms to generate and update data, uses cryptography technologies to ensure the security of data transmission and access, and uses smart contracts composed of automated script codes to program and operate data [2]. Through the integration of multiple technologies, the cluster jointly maintains the security and operation of the blockchain network and builds trust with machines.

Blockchain has four major supporting technologies: distributed database, consensus algorithm, secure cryptographic protocol, and smart contract. Based on the underlying key technologies of the blockchain, it has the following characteristics [3]: (1) Decentralization. There is no centralized hardware or management organization in the blockchain network. The rights and obligations of all nodes are equal, and the data in the system is maintained together. The suspension of any node does not affect the overall operation of the system.

Abstract

Introduction

Literature Review

Conclusion

References

Abstract

     Blockchain is the trending topic now-a-days due to its decentralized and security feature. Internet usage on the other hand is increasing rapidly along with the increase in threats and attacks. The Internet of Things, or IoT, is the arrangement of billions of physical devices around the world that are connected to the internet for the purpose of collecting and sharing data, worldwide. IoT appliances and devices are the boom in the technology but the biggest concern in IoT devices is its security. A lot of attacks are discussed on IoT. Existing technologies are not enough to secure the IoT devices completely. BIoT or Blockchain IoT is the mechanism of using security feature of Blockchain in IoT to make it more secure and vulnerable to communication attacks. In this paper we have discussed the basics of Blockchain, IoT and How various work have been varied out on BIoT.

Introduction

     Blockchain is a distributed ledger that contains data in an interconnected form of chains that are secured. Or one can easily understand it as a database that stores some kind of information in the interconnected blocks. Whenever any new data arrives then it is to be inserted into a new block. Once the block is ready with data it is to be inserted and interconnected with the previous existing blocks in that Blockchain in chronological order, by the help of hash techniques. The following figure shows the network of Blockchain.

     In Blockchain we can store different types of information or data that may be inter-related or totally different from each other. It is the emerging technique with wide variety of applications. Blockchain is gaining popularity because of its decentralized and secure nature. It uses Hashing technique to store hash of previous data is stored and a secure chain is formed that’s hard to manipulate. People are investing in Bitcoins and accepting the concept of Blockchain.

Conclusion

     Clearly it’s seen and observed that we are using BIoT in various applications and in coming years it will be scaled more in other application areas also. IoT is an emerging technique but in it security and privacy is not maintained. Blockchain is also a current emerging technique that is famous for its secure and decentralized nature. Together Blockchain IoT (BIoT) is used to make smart appliance more secure and private. In this paper we have reviewed the existing work and techniques in contribution to making IoT more secure in various applications like agriculture, automobile and healthcare etc.

Abstract

Document Sections

I. Introduction

II. Major Security Risks in IoT

III. Characteristics of Blockchain-Embedded IoT

IV. Classification of Security in IoT

V. Blockchain-Based IoT Attacks

VI. Blockchain-Based Information Sharing Security Mechanism for IoT

VII. IoT Security Scenarios Under Blockchain

VIII. Research Challenges and Future Trends

IX. Conclusion

Abstract:

In recent years, the Internet of Things (IoT) has made great progress. The interconnection between IoT and the Internet enables real-time information processing and transaction implementation through heterogeneous intelligent devices. But the security, the privacy, and the reliability of IoT are key challenges that limit its development. The features of the blockchain, such as decentralization, consensus mechanism, data encryption, and smart contracts, are suitable for building distributed IoT systems to prevent potential attacks and to reduce transaction costs. As a decentralized and transparent database platform, blockchain has the potential to raise the performance of IoT security to a higher level. This article systematically analyzes state of the art of IoT security based on the blockchain, paying special attention to the security features, issues, technologies, approaches, and related scenarios in blockchain-embedded IoT. The integration and interoperation of blockchain and IoT is an important and foreseeable development in the computational communication system.

I. Introduction

At present, the Internet of Things (IoT) is an enormous ecosystem. Its timeliness, convenience, inclusiveness, scalability, integration, and interoperability make IoT an unparalleled prospect for further development. Its applications extend to a wide range of fields, such as agriculture and food traceability, remote medicare and hospitality, location and navigation, logistics and operations, manufacturing and automation, smart city and home use, etc. At the same time, more and more security vulnerabilities have arisen—urgent issues that need to be solved. During the first half of 2017, the number of attacks on IoT devices increased by 280%. By 2021, corporate spending on information security related to IoT is projected to increase from the current 83.5 billion to 119.9 billion. Based on the architecture of IoT itself, many effective paradigms and protocols have been used to prevent or to eliminate potential security risks. But these have not been enough. IoT requires the assistance of appropriate technology and mechanisms to improve its overall security level. With the rapid development of the blockchain, its security functions have been revealed, and they have become potential approaches for IoT security, with a special focus on its decentralized and transparent system, as well as on its consensus mechanisms and privacy protocols, encrypted data and management, and smart contract agreement [1]–[4].

Blockchain is one of the disruptive technical innovation in the recent computing paradigm. Many applications already notoriously hard and complex are fortunate to ameliorate the service with the blessings of blockchain and smart contracts. The decentralized and autonomous execution with in-built transparency of blockchain based smart contracts revolutionize most of the applications with optimum and effective functionality. The paper explores the significant applications which already benefited from the smart contracts. We also highlight the future potential of the blockchain based smart contracts in these applications perspective.

1. Introduction

The blockchain is a decentralized, distributed and immutable ledger comprised of a cryptographically linked chain of record collection. The collection of records referred as blocks and the records called transactions or events. The decentralized ledger is shared within all contributory members in the blockchain network. These transactions add to the ledger upon verification and agreement process between the parties on-board in the blockchain. The important features associated with blockchain are the decentralization, immutability and cryptographic link.

Decentralization:The decentralization of blockchain delegate the authority among the contributors of the network. It is a distinction of the blockchain which ensure redundancy in contrast with the centralized systems operated by a trusted third party. The decentralization ensures the service availability, reduce the risk of failure and eventually improve the trust of service with guaranteed availability.

1- Introduction

2- Smart-building model

3- Smart-buildings community framework

4- Case study and discussion

5- Conclusion

References

Abstract

Demand Response (DR) is progressively moving from a centralized, unidirectional structure to a set of advanced decentralized mechanisms that better balance distributed supply and demand. This paper presents a decentralized cooperative DR framework to manage the daily energy exchanges within a community of Smart-Buildings, in the presence of local Renewable Energy Sources (RES). The proposed algorithm taps into the flexibility of the participants to let them decide of a day-ahead community power profile, and subsequently ensures the forecast tracking during the next day. In practice, the algorithm is fully decentralized by the Blockchain technology, that enables a trusted communication medium among the participants and enforces autonomous monitoring and billing via Smart-Contracts. With such an energy management framework, participating Smart-Buildings can together aim at a common objective, such as carbon-free resources usage or aggregated grid services, without depending on a centralized aggregator/utility. Simulations on realistic Swiss building models demonstrate that nearly all the renewable production resources could be harnessed locally through the presented framework, compared to selfish individual optimization. Under a quadratic cost of grid electricity, the considered community profile could dramatically be flattened, hence avoiding costly peaks at the grid interface. A scalability analysis shows that, considering the current public Ethereum Blockchain, the framework could handle a community size of up to 100 Smart-Buildings.

Introduction

The increasing world demand in electricity is envisioned to be entirely supplied by sustainable Renewable Energy Source (RES) in order to counteract the global climate change. However, intrinsic volatility and uncontrollably of decentralized RES production pose severe challenges to the current electrical grid, that must ensure stability at any time. Progressively, the centralized grid sees a change in paradigms, transitioning from a system dispatching a production portfolio following the electrical demand to a Smart-Grid that handles a portfolio of controllable demand to match an uncontrollable supply [1]. To assist this transition, Smart-Buildings have recently emerged as a solution to leverage the flexibility offered by the various entities commonly found in buildings. Equipped with the right hardware and Information and Communication Technology (ICT) they can provide active Demand Response (DR) to the electrical grid [2,3]. DR regroups a set of mechanisms divided into incentive and price-based programs, that specify various signals to be exchanged between the grid and the consumers in order to shape the power profile of the latter. Many works have tackled the problem at individual building level, demonstrating their capability to adapt their power consumption to grid signals while ensuring occupant comfort [4–7]. Beyond individual building optimization, there is a need of handling the problem at the community level. By doing so, local resources such as Photovoltaic (PV) production can optimally be harnessed while reducing the overall peak power demand. Many optimization frameworks have emerged to collectively manage the energy of multiple users [8–12]. Nevertheless, these solutions require a central agent that collects user information to subsequently dispatch optimal set points to each of them. Even though generic simplified models can be used to represent buildings flexibility [9,12], centralized solutions still face issues of privacy, single point of failure, scalability, and market entry of small prosumers.

1. Introduction

2. Blockchain: background and architecture

3. Smart city: characteristics, pillars and security requirements

4. Motivations for Integration of Blockchain and Smart Cities

5. Blockchain in smart cities

6. Open issues and future research directions

7. Conclusion

References

Abstract

In recent years, smart city has emerged as a new paradigm to provide high quality facilities to the citizens by dynamically optimising the city resources. Smart cities can offer finest services for boosting the daily life of citizens on healthcare, transportation, energy consumption, and education. However, the concept of smart city is still evolving and despite its potential vision, there are proliferating security challenges. Blockchain has the potential to promote the development of smart cities owing to its good properties such as auditability, transparency, immutability and decentralization. Therefore, this paper presents the state-of-the-art blockchain technology to solve the security issues of smart cities. Initially, the paper throws light on the background knowledge and then surveys the utility of blockchain in various smart communities such as healthcare, transportation, smart grid, supply chain management, financial systems and data center networks. Finally, some future research directions are identified through extensive literature survey on blockchain based smart city systems.

Introduction

The past few decades have witnessed a meteoric rise in the world’s population that lived in urban area. Nowadays, more than 55 % of the world population are living in urban areas and over the next 30 years, this rate is predicted to reach 70 %, as by 2050, an additional 25 billion people are predicted to move to urban areas [1,2]. The explosive growth in the world’s population coupled with the rapid urbanisation process brings forth numerous social, technical, organizational and economic problems, which tend to endanger the environmental and economical sustainability of cities. Hence, majority of governments are actively interested in adopting “smart” concepts to optimize the use of both tangible (e.g., natural resources, energy distribution networks, and transport infrastructures) and intangible assets (e.g., organizational capital in public administration systems, intellectual capital of companies and human capital) [3, 4]. In this regard, the concept of “Smart City” is proposed that use modern Information and Communication technology (ICT) in an intelligent manner aimed to build a sustainable urban environment and improve the QoL. The smart city has huge range of applications in the modern societies such as smart building for managing the temperature and lighting system [5]; smart energy for optimizing energy consumption using digital technologies; smart healthcare to promote diagnostics [6 – 8]; smart technology to enable edge processing and intelligent network connectivity [9]; smart education to facilitate the education system using modern technologies; smart governance to provide digital services and policies from the government [10]; smart security to reduce security risks and protect properties, people and information [11].

Data sharing techniques have progressively drawn increasing attention as a means of significantly reducing repetitive work. However, in the process of data sharing, the challenges regarding formation of mutual-trust relationships and increasing the level of user participation are yet to be solved. The existing solution is to use a third party as a trust organization for data sharing, but there is no dynamic incentive mechanism for data sharing with a large number of users. Blockchain 2.0 with smart contract has the natural advantage of being able to enable trust and automated transactions between a large number of users. This paper proposes a data sharing incentive model based on evolutionary game theory using blockchain with smart contract. The smart contract mechanism can dynamically control the excitation parameters and continuously encourages users to participate in data sharing.

Introduction

In the era of big data, digital resources have grown exponentially, and data has become an important strategic resource. At present, the big data industry faces a dilemma referred to as the problem of “data islands”. An effective solution to this problem would be to establish a reasonable and effective data sharing model [1]. Today, information disclosure and open sharing of data have become general trends in scientific, and even national, innovation. Numerous studies have shown that data sharing and reuse are conducive to accelerating the dissemination of data resources, by improving the efficiency and quality of work, and enhancing the potential for innovation [2–5]. Although data sharing has varying applications, it provides significant convenience in daily life. However, in the process of data sharing, there are still three problems to be solved: unwillingness to share, fear of sharing, and inability to share [6]. The unwillingness of users to share data is affected by the formation of mutual-trust relationships and the economic utility of data sharing. However, little research has been conducted on data sharing in the big data era and with the support of blockchain technology. In this paper, we perform an evolutionary game equilibrium analysis of data sharing in the era of big data, and explore and analyze the evolutionary game process of data sharing. Finally, we obtain four constraints with which to design an adaptive smart contract mechanism that can be used to motivate more users to participate in data sharing.

Abstract

As Internet of Things (IoT) devices and other remote patient monitoring systems increase in popularity, security concerns about the transfer and logging of data transactions arise. In order to handle the protected health information (PHI) generated by these devices, we propose utilizing blockchain-based smart contracts to facilitate secure analysis and management of medical sensors. Using a private blockchain based on the Ethereum protocol, we created a system where the sensors communicate with a smart device that calls smart contracts and writes records of all events on the blockchain. This smart contract system would support real-time patient monitoring and medical interventions by sending notifications to patients and medical professionals, while also maintaining a secure record of who has initiated these activities. This would resolve many security vulnerabilities associated with remote patient monitoring and automate the delivery of notifications to all involved parties in a HIPAA compliant manner.

Introduction

The rapid growth of Internet of Things (IoT) devices and wearable technology has opened up new possibilities in the realm of medical sensors, particularly for remote patient monitoring. One subset of this IoT healthcare trend is This article is part of the Topical Collection on Mobile & Wireless Health Thaier Hayajneh thayajneh@fordham.edu Kristen N. Griggs kgriggs2@fordham.edu Olya Ossipova oossipova@fordham.edu Christopher P. Kohlios ckohlios@fordham.edu Alessandro N. Baccarini abaccarini@fordham.edu Emily A. Howson ehowson@fordham.edu 1 Fordham Center for Cybersecurity, Fordham University, New York, USA Wireless Body Area Networks (WBANs). In a WBAN, a patient is equipped with various wearable or implanted medical devices that take real-time measurements of vital indicators, such as heart rates or glucose levels. Other devices may act as actuators, which can provide automated treatments based on the measurements taken by the sensors. All of the patient’s WBAN devices report to a master device (typically a mobile phone) which transmits the collected data to healthcare providers and provides an interactive interface for the user. This remote monitoring reduces the need for time-consuming doctor’s appointments and allows patients to go about their daily lives more freely [3].

In the Internet of Things (IoT) vision, conventional devices become smart and autonomous. This vision is turning into a reality thanks to advances in technology, but there are still challenges to address, particularly in the security domain e.g., data reliability. Taking into account the predicted evolution of the IoT in the coming years, it is necessary to provide confidence in this huge incoming information source. Blockchain has emerged as a key technology that will transform the way in which we share information. Building trust in distributed environments without the need for authorities is a technological advance that has the potential to change many industries, the IoT among them. Disruptive technologies such as big data and cloud computing have been leveraged by IoT to overcome its limitations since its conception, and we think blockchain will be one of the next ones. This paper focuses on this relationship, investigates challenges in blockchain IoT applications, and surveys the most relevant work in order to analyze how blockchain could potentially improve the IoT. © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Introduction

The rapid evolution in miniaturization, electronics and wireless communication technologies have contributed to unprecedented advances in our society. This has resulted in an increase in the number of suitable electronic devices for many areas, a reduction in their production costs and a paradigm shift from the real world into the digital world. Therefore, the way in which we interact with each other and with the environment has changed, using current technology to gain a better understanding of the world. The Internet of Things (IoT) has emerged as a set of technologies from Wireless Sensors Networks (WSN) to Radio Frequency Identification (RFID), that provide the capabilities to sense, actuate with and communicate over the Internet [1]. Nowadays, an IoT device can be an electronic device from a wearable to a hardware development platform and the range of applications where it can be used encompass many areas of the society. The IoT plays a central role in turning current cities into smart cities, electrical grids into smart grids and houses into smart homes, and this is only the beginning. According to various research reports, the number of connected devices is predicted to reach anywhere from 20 to 50 billion by 2020 [2] mainly due to the vast number of devices that the IoT can place on the scene. The IoT visualizes a totally connected world, where things are able to communicate measured data and interact with each other. This makes possible a digital representation of the real world, through which many smart applications in a variety of industries can be developed. These include: Smart homes, Weareables, Smart cities, Healthcare, Automotive, Environment, Smart water, Smart grid, etc. IoT solutions are being deployed in many areas, optimizing production and digitizing industries. IoT applications have very specific characteristics, they generate large volumes of data and require connectivity and power for long periods. This, together with the limitations in memory, computer capacity, networks and limited power supply pose a high number of challenges. The huge expansion of the IoT has to be supported by standard mechanisms and protocols in order to reduce the existing heterogeneity in the field. This heterogeneity leads to vertical silos and reduces the adoption of the IoT. However, aside from the heterogeneity and integration challenges present in the IoT, the trustworthiness of its data is also an important issue to bear in mind. Nowadays, we trust in the information of financial entities and the government among others, but can we be sure that the information provided by them and by other external entities, such as IoT companies, has not been tampered/altered/falsified in any way? This is a difficult question to answer in centralized architectures. Untrusted entities can alter information according to their own interests, so the information they provide might not be completely reliable. This brings about the need to verify that the information has never been modified.

Blockchain has recently joined a long line of technological innovations that have been characterised as disruptive to, and possibly even subversive of, fundamental legal principles. This article looks behind the hype to examine how blockchain might – or might not – be compatible with established legal and regulatory models. Data protection is discussed as an example of an area of law that some have claimed cannot be reconciled with blockchain. Various other conflicts are also identified and concerns about blockchain are placed in the context of wider historical debates about new technologies vs law.

The history of technologies, not least information technologies, is replete with claims that a particular development will be highly ‘disruptive’ and will render obsolete established legal norms and regulatory frameworks. Perhaps the most dramatic illustration is the enthusiastic reception that cyberlibertarians gave the public Internet in the mid-1990s. At the time, some forecast not merely that specific legal constructs would be challenged, but that nation states would become obsolete. In that debate, the most famous example was the late John Perry-Barlow’s 1996 ‘Declaration of the Independence of Cyberspace’.1 This included assertions that: “Governments of the Industrial World… You have no sovereignty where we gather…. Your legal concepts of property, expression, identity, movement, and context do not apply to us. They are based on matter, and there is no matter here.” This rallying cry was wildly popular and many early web sites reproduced the full text or at least linked to it. Reports of the death of sovereignty were, however, exaggerated. When asked in 2004 to comment on his revolutionary tract, Barlow responded simply: “We all get older and wiser”. In fact, there has long been evidence that ‘online’ activities are likely to be subject, at least nominally, to more legal rules, and broader regulatory oversight, than comparable ‘offline’ activities.2 Admittedly, new technologies do not always fit easily into existing legislative and regulatory paradigms, and enforcement may be challenging, but lawmakers, regulators, and courts have so far managed to adapt, albeit with a time lag, to each wave of innovation. A recent technological development that is provoking agitated debates, and attracting a lot of media attention, is blockchain. Most of the current hype about blockchain relates to crypto-currencies, especially Bitcoin, and related financial products such as Initial Coin Offerings (ICOs). Concerns have been raised that, like the early Internet, blockchain-based financial systems may be unregulated, and possibly even ‘unregulatable’. Less visibly, but probably far more importantly in the long run, a great deal of investment is going into the development of a broad range of blockchain applications in contexts ranging from asset registration (including land) to self-executing (‘smart’) contracts. Notwithstanding widespread confusion about what exactly blockchain is or might become, blockchain and distributed ledger technologies (DLT) have caught the imagination of governments, businesses and private investors, and they are increasingly a focus of attention for legislators and regulators worldwide.

Abstract

Motivated by the recent explosion of interest around blockchains, we examine whether they make a good fit for the Internet of Things (IoT) sector. Blockchains allow us to have a distributed peer-to-peer network where non-trusting members can interact with each other without a trusted intermediary, in a verifiable manner. We review how this mechanism works and also look into smart contracts-scripts that reside on the blockchain that allow for the automation of multi-step processes. We then move into the IoT domain, and describe how a blockchain-IoT combination: 1) facilitates the sharing of services and resources leading to the creation of a marketplace of services between devices and 2) allows us to automate in a cryptographically verifiable manner several existing, time-consuming workflows. We also point out certain issues that should be considered before the deployment of a blockchain network in an IoT setting: from transactional privacy to the expected value of the digitized assets traded on the network. Wherever applicable, we identify solutions and workarounds. Our conclusion is that the blockchain-IoT combination is powerful and can cause significant transformations across several industries, paving the way for new business models and novel, distributed applications.

Introduction

Blockchains have recently attracted the interest of stakeholders across a wide span of industries: from finance [1] and healthcare [2], [3], to utilities [4], real estate [5], [6], and the government sector [7]. The reason for this explosion of interest: With a blockchain in place, applications that could previously run only through a trusted intermediary, can now operate in a decentralized fashion, without the need for a central authority, and achieve the same functionality with the same amount of certainty. This was simply not possible before.