Machine Learning Approaches for Convergence of IoT and Blockchain. Группа авторов

common application of blockchain is seen in the cryptographic currency of Bitcoin. Cryptocurrency is a completely digital form of money. A distinctive feature of transaction with Bitcoins is that there is no requirement for a mediating institution. A conventional electronic payment involves third party other than the buyer and seller, usually a bank that facilitates the transfer of money. This technology of Bitcoin eliminates the need of any such mediation. Also, the Bitcoins are decentralized which implies that their distribution and circulation globally can be monitored by a government or any similar organisation. Whenever a bitcoin transaction occurs, the blockchain records the sender’s and receiver’s Bitcoin addresses along with the amount. Each transaction is encrypted with public key cryptography and verified by multiple nodes; these transactions cannot be tampered with. The computers than individuals connect onto this network are referred to as bitcoin miners. The cost of entering into the Bitcoin network is fairly high and bitcoins can only be profitably mined using specialized devices. As the number of nodes in the network increases the difficulty of mining generally increases. What attracts people to bitcoins is to keep their money safe in a bitcoin network as compared to any bank. Some people see it as an investment but there happens to be lot of risk but it is claimed that by 2040 this network will be very well established. Even though we presently seem to observe bitcoins as the only major application of blockchain, a lot of scope beholds for this technology some aspects of which we will be coming across through the course of this chapter [6].

      Another growing application of blockchain is the Smart contract. The purpose of smart contract resembles just what a usual contract does i.e., beholds conditions, clauses and agreements. The only difference is that here they are stored as a few lines of code that is kept safe inside a blockchain. Also, this technology allows two parties to bind a contract without the requirement of any third party mediation. These are beneficial and binding as once the details of a smart contract are put in to a blockchain they cannot be modified. We specify the terms and condition of the contact along with the fulfilment condition, this is an efficient means to seal a contract because once made it cannot be manipulated or breached. For example, person A promises to deliver a commodity to person B after exactly 1 year from signing the contract. In this case a smart contract may be brought to effect specifying that the payment made by person B shall only be received by person A on the fulfilment of the contract, till then it may be held as cryptocurrency within the smart contract.

      The drawback associated with the bitcoin application of blockchain technology is that the value of a bit coin is highly variable and thus faces a lot of risk. Also this technology demands for very high energy consumption. The data stored in a blockchain is immutable which particularly serves as an advantage and a disadvantage at the same time. Along with these, blockchain technology possesses a high implementation cost. Finally, this technology is not yet standardized or practiced regularly creating an air of ambiguity about it.

1.4 What is IoT?

IoT stands for Internet of Things. The motive of using IoT is to connect the physical devices present across the globe to each other via a wireless network and to allow them to communicate without any human interference as depicted in Figure 1.3. In today’s world, we witnesses the impact of IoT in our daily lives ranging from the way we drive to how we attain energy in our homes. Some simple examples of IoT that we come across nowadays are say a light bulb that can be switched on using a mobile application. Here, the mobile and the light bulb are allowed to communicate without any human interruption to perform a task, which in this case is to switch the bulb on or off. We witness IoT through various complexities ranging from maybe a child’s stuff toy to much more complex applications such as highly specialized healthcare. A brief insight into the history of IoT tells us that the term “Internet of Things” was coined by Kevin Ashton; however, the concept of connected devices came into existence long back dating to 1830s when the first electronic telegraph was developed. This field has gained a lot of sophistication since then and stands at the levels we see it at today and there yet lies more scope to unveil its advanced applications further.

Figure 1.3 Illustration of IoT.

But firstly let us see how IoT works. Four basic contents for IoT are sensors, connectivity, data processing, and finally a user interface. The first key requirement for any device connected to IoT is to first be able to gather the information that it wants to process and communicate to other devices over the network. This is possible with the help of sensors, since they can detect an event or change in the environment of the device that they are attached to. The sensors may be in the form of cameras, microphones, motion sensors, accelerometers, temperature sensors, etc., allowing any device to know its surroundings without requiring any human interventions. The information or data through these sensors is continuously sent to a cloud or server that the device is connected to from where other devices which have access to that server may attain the information. The information from the cloud is utilized for performing certain tasks without the need of any human to machine or human to human interaction. This technology allows us to refer to devices as smart devices since they are capable to perform some activities on their own when required to do so. Let us consider a common example, smart watches have seen a surge in the number of people using it. These watches gather and present data such as, lets the user know about the number of steps that he took throughout the day, the distance covered, their pulse rate, their body temperatures, some also notify when they sense a surge in heart rate or suspect a medical condition, in case a call or text message notification is received. All this has been made possible with the use of sensors and the technology of IoT. Another example that we all have heard about is Amazon’s Alexa or Google home, these function on voice commands given by the user with the help of sensors that convert verbal instructions into commands understandable by the device’s software and then converts the device’s output into speech to be delivered back to the user, such appliance is also referred to as a chat bot. These may also be configured with smart lighting system or may regulate ac controls with the help of IoT [7]. One widely applicable benefit of IoT is prognostics and advanced system health management (PHM). Herein, we are able to keep a check on the reliability of a device; reliability implies how the asset would perform under the expected set of conditions. This is done by in situ sensing. In situ sensing implies accommodating sensors in various parts under the same environment as the particular area that this sensor is responsible for providing details about. Four dimensions of prognostics and systems health management are sensing, diagnosis, prognosis, and management. Sensors are embedded across different machine parts, and these sensors provide data regarding time-based degradation of the particular part and notify if any anomaly arises. Diagnosis implies extraction of complete fault related information from the signals received by the sensors and lets us know about the amount of damage and provides warning regarding need for replacement or repair in advance. Prognostics help us figure out the remaining life of the equipment and calculate when it would require replacement so that it can be done as per need and sudden disruption can be avoided. Finally, management implies deciding how to tackle the requirements of the machine and performing the procedures accordingly [8]. However, with the advancement and automation that is brought about by this technology, accompanying it are concerns regarding the security issues that may arise due to this technology. Threats such as unauthorized access, phishing, or hacking surround, since it is a digitally augmented space. It is essential to have solutions to such problems or else it would not be possible to benefit from this technology. One solution suggested to tackle this is to combine the technology of IoT with the support of blockchain technology. How we benefit from this will be seen in better detail in the following section.

1.5 Combining IoT and Blockchain

As we have already seen, IoT connects and facilitates communication for devices connected to each other via the internet and provides storage space over a cloud, thus enabling devices to establish communication between one another and interact to successfully perform certain tasks without