Next Generation IoT and Blockchain Integration

Abstract

The Internet of Things (IoT) refers to the interconnection of smart devices to collect data and make intelligent decisions. However, a lack of intrinsic security measures makes next generation IoT more vulnerable to privacy and security threats. With its “security by design,” Blockchain (BC) can help in addressing major security requirements in IoT. Blockchain is an ever-growing list of records that are linked and protected using cryptographic methods. It offers its users the flexibility to conduct transactions with lower costs and faster speeds. Blockchain ledgers are also decentralized and a ledger is maintained at each node in the network. Blockchain’s security and adaptability help in making even entire systems on it a much easily task with the benefit of decentralization. BC capabilities like immutability, transparency, auditability, data encryption, and operational resilience can help solve most architectural shortcomings of IoT. In the vision of the Internet of Things, traditional devices are becoming smarter and more autonomous. This vision is becoming reality as technology advances but there are still challenges to be resolved. This is especially true in a security domain like data trust, and with the expected evolution of the IoT in the coming years, it is important to ensure that this great source of data arrives. This paper began with an overview of blockchain and IoT, as well as explore the IoT blockchain application challenges. This article also focuses to review the most relevant tasks to analyse how IoT blockchain can improve and examine current research concerns and developments in the use of blockchain-related techniques and technologies in the context of IoT security in depth. One of the best parts of working or learning about blockchain and its application is the curiosity about how it can impact the things that we have been accustomed to without trying to improve and make things more efficient and productive.

Full text

Review Article
Next Generation IoT and Blockchain Integration
Sarvesh Tanwar,
1
Neelam Gupta,
1
Celestine Iwendi ,
2
Karan Kumar ,
3
and Mamdouh Alenezi
4
1
Amity Institute of Information Technology, Amity University Uttar Pradesh, Noida, India
2
School of Creative Technologies, University of Bolton, Bolton BL3 5AB, UK
3
Electronics and Communication Engineering Department, Maharishi Markandeshwar Engineering College,
Maharishi Markandeshwar (Deemed to Be University), Mullana, Ambala, 133207 Haryana, India
4
College of Computer & Information Sciences, Prince Sultan University, Riyadh, Saudi Arabia
Correspondence should be addressed to Celestine Iwendi; celestine.iwendi@ieee.org, Karan Kumar; karan.170987@gmail.com,
and Mamdouh Alenezi; malenezi@psu.edu.sa
Received 15 July 2022; Accepted 11 August 2022; Published 24 August 2022
Academic Editor: Sweta Bhattacharya
Copyright © 2022 Sarvesh Tanwar et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
The Internet of Things (IoT) refers to the interconnection of smart devices to collect data and make intelligent decisions. However,
a lack of intrinsic security measures makes next generation IoT more vulnerable to privacy and security threats. With its “security
by design,”Blockchain (BC) can help in addressing major security requirements in IoT. Blockchain is an ever-growing list of
records that are linked and protected using cryptographic methods. It offers its users the flexibility to conduct transactions
with lower costs and faster speeds. Blockchain ledgers are also decentralized and a ledger is maintained at each node in the
network. Blockchain’s security and adaptability help in making even entire systems on it a much easily task with the benefitof
decentralization. BC capabilities like immutability, transparency, auditability, data encryption, and operational resilience can
help solve most architectural shortcomings of IoT. In the vision of the Internet of Things, traditional devices are becoming
smarter and more autonomous. This vision is becoming reality as technology advances but there are still challenges to be
resolved. This is especially true in a security domain like data trust, and with the expected evolution of the IoT in the coming
years, it is important to ensure that this great source of data arrives. This paper began with an overview of blockchain and IoT,
as well as explore the IoT blockchain application challenges. This article also focuses to review the most relevant tasks to
analyse how IoT blockchain can improve and examine current research concerns and developments in the use of blockchain-
related techniques and technologies in the context of IoT security in depth. One of the best parts of working or learning about
blockchain and its application is the curiosity about how it can impact the things that we have been accustomed to without
trying to improve and make things more efficient and productive.
1. Introduction
Recently, the rapid advancement of blockchain technology
and digital currencies has had an impact on the financial
industry, resulting in the creation of a new crypto economy.
These usages are growing with the number of areas such as
Internet, banking sector, industry, and medical center secu-
rity. In addition, IoT [1] has expanded its adoption by the
development of urban development around the world. The
IoT has evolved into a collection of technologies ranging
from wireless sensor networks (WSN) to radio frequency
identification. (RFID) is used to identify, exploit, and com-
municate on the Internet. Today, IoT devices can range from
wearables to hardware development platforms to electronic
devices. IoT plays an important role in transforming today’s
cities into smart cities with a wide range of applications that
can be used in many sectors of society. Various research [2]
reports predict that the number of connected devices will
reach 20 to 50 billion by 2020, mainly due to the large num-
ber of devices that IoT can deploy.
The IoT envisions a fully connected world where mea-
surable information can communicate and interact with
Hindawi
Journal of Sensors
Volume 2022, Article ID 9077348, 14 pages
https://doi.org/10.1155/2022/9077348

objects. This allows a digital representation of the real
world, and it can develop many smart applications in var-
ious industries, including smart home, wearables, smart
city, healthcare, automotive, environment, smart water,
and smart grid. A screenshot of a word cloud built in
the research is utilizing the most commonly appearing
author’s keywords, as shown in Figure 1. To increase pro-
ductivity, IoT applications [3] in the digital industry are
very clear, generating large amounts of data requires a
long connection and energy. Limited storage, compute,
networking, and power supply capabilities pose a number
of challenges. Standard mechanisms and protocols must
support the massive expansion of IoT. This separation
has led to a decrease in vertical silos and the adoption
of IoT to reduce the diversity present in the region. How-
ever, in addition to the diversity and inclusion challenges
that exist in the IoT, data credibility is also an important
issue to consider when dealing with data from financial
and government institutions. But how can we ensure that
information received from external parties and other
external bodies. IoT companies will not be distorted/
altered/falsified in any way? This question is difficult to
answer in a centralized architecture [4, 40]. Unreliable
organizations may modify the information according to
their own interests. As such, the information they provide
may be completely uncertain. This raises the need to verify
that the data has never been updated. One way to trust
IoT data is to use a distributed service that all stakeholders
trust to ensure that the data remains unchanged. If all par-
ticipants have data, there is a way to verify that the data
has not been tampered with since it was first defined.
Moreover, a system that guarantees the reliability of infor-
mation will enable governments to securely share and
share information with citizens.
The appearance of smart contracts, which are personal
computer conventions meant to work with, confirm, and
sanction naturally the exchange and arrangement among
various deceptive gatherings, has therefore resulted in cut-
ting edge decentralized apps without the involvement of a
presumed outsider. Despite the positive aspects of clever
agreements, a few concerns, like security risks, flaws, and
real concerns, continue to sabotage their acceptance. For
over 10 years, the blockchain [5] has been laid out as an
innovation where a circulated data set records every one of
the exchanges that have occurred in a distributed organiza-
tion. Viewed as a disseminated figuring worldview effectively
beats the issue connected with the trust of an incorporated
party. Hence, in a blockchain network, a few hubs work
together among them to get and keep a bunch of shared
exchange records in a disseminated manner without
depending on any confided in party. In 2008, Satoshi Naka-
moto presented Bitcoin that was the main proposed crypto-
graphic money presenting the blockchain as an appropriated
infrastructural innovation. It permitted clients to safely
move cryptographic forms of money, known as bitcoins
without a unified controller. In addition, Ethereum, NXT,
and Hyperledger Fabric (world greatest open source block-
chain made by Linux Establishment in which organizations
like IBM were a giver) were likewise proposed as
blockchain-based frameworks utilized for the digital money
[6]. Not at all like Bitcoin, they can utilize shrewd agree-
ments. Blockchain innovation covers conventional agree-
ments by including the terms of arrangements between at
least two gatherings, however, outperforms them because
of brilliant agreements via computerizing the execution of
arrangements in a dispersed climate when conditions are
met.
Despite the fact that smart contracts have recently
acquired traction, they nevertheless face numerous chal-
lenges. For example, due to its re-entrancy weakness, the
Decentralized Independent Association (DAO) agreement
was controlled to take around 2 million Ether (50 million
USD at the time) [2, 7]. Aside from the issue of weakness,
brilliant agreements confront a number of challenges,
including questions of protection, legality, and execution.
The following paper is represented as follows: Section 2
presents about Internet of Things with IoT security and
security using blockchain. The literature review about inte-
gration of IoT blockchain and timeline over the last six year
is presented in Section 3. Section 4 describes the blockchain
and IoT integration with importance of integration. Chal-
lenges of integration of IoT in blockchain are presented in
Section 5. The final section of the paper includes some con-
cluding observations.
Figure 1: A snapshot of a word cloud built in the research utilizing the most commonly appearing author’s keywords.
2 Journal of Sensors

1.1. Authors’Contributions. Authors addressed major secu-
rity requirements in IoT and provided solution by intro-
ducing BC capabilities to overcome IoT security issues.
Searching relevant documents is an important component
of performing a systematic review. This article focused
on the review of the most relevant publications in the field
of IoT and BC integration. The investigation is based on
publications found in the Scopus electronic database to
analyse how IoT BC can be improved and examined cur-
rent research.
2. The Internet of Things
The way we interact with the environment and each other
has changed dramatically Internet of Things (IoT) technol-
ogy is a very widespread technology. It should shape human
life. Make big financial gains IoT and blockchain technology
can present a variety of challenges. Some IoT devices are
sold with built-in functionality to connect to the embedded
blockchain [8]. The company responsible for Ethereum
allows the use of nodes on devices such as Odroid, Beagle-
bone, and Ethereum. Raspberry Pi Similarly, EthRaspbian,
and Raspnode have the ability to install Bitcoin, Litecoin,
and Ethereum nodes on the Raspberry PI. The Raspnode
Wi-Fi Router Wallet also supports Litecoin and Bitcoin.
Anrouter R-LTC also has this capability. Litecoin is mined,
so this router can be easily installed on the IoT network as
part of the Fog computing platform. It is still in its infancy
and requires a lot of research for further integration. Some
IoT devices also have a mining function. Not all IoT devices
have this capability. Because it requires high-end hardware
and invalidation on IoT devices, IoT mining is often not
found to solve these challenges. The Internet of Things
(IoT) offers a multitude of aspects of life. Our daily life is
strongly influenced by the many applications in areas such
as healthcare and manufacturing. IoT plays an important
role in transforming homes into smart homes and cities.
Blockchain has to deal with many inherent complexities of
IoT [9] to become a smart city. Isolated integrating block-
chain with IoT will build trust between customers and
devices and reduce costs such as cutting out middlemen.
Transactions will be much faster, and for blockchain integra-
tion to work primarily for IoT purposes, it is necessary to
connect some aspects like scalability. Collaboration security
requires transcending blockchain into the IoT. Blockchain
is for them to harness the power of each other. Blockchain
and IoT are interdependent and evolving. Blockchain is an
opportunity provided by IoT, and IoT is essential to the
functions of blockchain exist. Blockchain provides a service
layer for integration with standard IoT frameworks. In gen-
eral, frameworks play three main roles: sensors, miners, and
agents. IoT sensors receive data and interact with services
using blockchain agents. The sensors are not integrated with
the blockchain function [10]. Transactions in the form of
sensory information can be interpreted and then transmitted
over a network. These agents also provide security through
the use of private keys. IoT devices do not have this security.
Network miners use the main function of the blockchain to
verify transactions and place them in blocks.
The Internet of Things, as shown in Figure 2, is made up
of devices that generate, process, and share massive volumes
of security and safety-critical data as well as privacy-sensitive
data, making them attractive targets for cyberattacks [43].
Many of the new networkable devices that make up the
Internet of Things [11] are low-power and lightweight.
These devices must concentrate the majority of their avail-
able energy and processing to executing core application
functions, making it difficult to enable security and privacy
in a cost-effective manner. In terms of energy usage and pro-
cessing overhead, traditional security methods are often too
expensive for IoT. Furthermore, because of the difficulty of
scale, the many-to-one nature of the traffic, and single point
of failure, many state-of-the-art security frameworks are
extremely centralized and hence are not necessarily well-
suited for IoT.
2.1. IoT Security. Notwithstanding the benefits provided by
IoT services, where IoT technology is successfully imple-
mented on lamps, refrigerators, air conditioners, washing
machines, wristwatches, mobile phones, etc., managing IoT
[12] communications has become a challenge. A large num-
ber of IoT devices can be installed anywhere the end-user
Internet of things
Network suitable for the exchange between objects.
Distribution of connected objects particularly in smart stores.
Datavenue: Data & IoT solution and services for businesses regarding collection,
storage, security, processing and availability of data generated by connected objects.
Value added services in health, wellbeing, the connected home
on the smart city.
Figure 2: Internet of Things.
3Journal of Sensors

wants, leaving them unattended and being a desirable target
for others to attack. In addition, manufacturers do not con-
sider the security of these devices because of the large-scale
deployment of IoT devices. For bulk-manufactured devices,
default usernames and passwords are the same. Many IoT
devices are shipped with a preprogrammed key that cannot
be changed. In addition, IoT networks are heterogeneous
and dynamic in nature, allowing various (untrusted) devices
to indefinitely join the network. In the event of a hack,
device intentions may differ during connection time, or
malicious devices may masquerade as benign. Data integrity
is another issue in IoT security. One of the most important
IoT applications is the decision support system [3]. The
information gathered by the sensors can be used to make
timely decisions. As a result, the system must be protected
from injection attacks, which attempt to inject false mea-
sures and thus influence decision-making.
2.2. IoT Security Using Blockchain. Moving towards decen-
tralized architectures, blockchain technology has gained tre-
mendous attention in terms of addressing security,
anonymity, traceability, and centralization. Entities and
methods are enforcing security and privacy properties in dif-
ferent tiers of IoT security using blockchain, as shown in
Table 1. The security [13] of this technology stems from
the use of hash functions to chain blocks to ensure immuta-
bility, as well as the use of encryption and digital signatures
to secure data. The distributed nature of the blockchain
ensures its availability. Enabling blockchain technology in
IoT can help to achieve a properly distributed consensus
based IoT system that overcomes security issues. Even if this
is an ideal match, it is still a challenging endeavor. Most
existing blockchain schemes do not work in the IoT ecosys-
tem and cannot meet the specific needs of the IoT. IoT envi-
ronments are resource-constrained, computationally,
power-intensive, and storage-constrained, resulting in high
computational complexity, limited scalability, high band-
width overhead, and high latency blockchain. There are
some devices that are not recommended to be use with
IoT. This is due to how the Block name manages device
identities [14]. The author uses an open source implementa-
tion of the Kademlia Distributed Hash Table (DHT) which
provides the secure encrypted communication, thus define
how devices are used with smart contracts. Fakhri and Muti-
jarsa built IoT systems with and without blockchain and
compared the two approaches. MQTT is a communication
protocol used in IoT systems that do not use blockchain.
Ethereum was used as a blockchain platform, along with a
smart contract, in the other system. The security levels of
both IoT systems were evaluated by simulating attacks and
observing their security features. The results of the tests
showed that the IoT system based on blockchain technology
had a higher level of security than the IoT system that did
not use blockchain technology. Mik presented a novel
hybrid blockchain architecture for IoT, referred to as Hybrid
IoT. In Hybrid IoT [15], subgroups of IoT devices, referred
to as PoW (proof of work) subblockchains, were created.
The connection between the PoW subblockchains was then
made using a Byzantine Fault Tolerance (BFT) interconnec-
tor framework, such as Cosmos or Polkadot. The authors’
work focused on the formation of PoW subblockchains that
are guided by a set of metrics, dimensions, and bounds. The
performance evaluation validated the PoW subblockchain
design according to the guidelines of the sweet-spot. The
results showed that the guidelines of sweet-spot help to pre-
vent security vulnerabilities. To provide an IoT network with
a scalable and dynamic communication architecture, a
dynamic blockchain-based trust system was proposed in.
The proposed architecture practically labelled all IoT devices
and mapped them as full nodes and lightweight nodes. If the
attacker pretends to be a full node, high-level security verifi-
cation will either catch him or make the attack extremely
costly [4]. It is also difficult if the attacker just wants to pre-
tend to be a lightweight node because all history is recorded
and the attacker must fake everything all over again each
time they try to attack. However, IoT with blockchain topol-
ogy should not only manage the ID but also protect the
information exchanged in the IoT network.
3. Literature Review
Various problems in IoT despite authentication and best
methods for incorporating security such as Zhen Ling, Junz-
hou Luo et al. (2017), Yiling Xu et al. (2017), Chao Gao et al.
(2017), Kui Wu et al. (2017), and Xinwen Fu et al. (2017)
found that there are numerous challenges that arise when
there is an authentication method (2017). The lack of an
authentication mechanism in the IoT is the fundamental
Table 1: Entities and methods enforcing security and privacy properties in different tiers.
Properties Smart home Overlay network Cloud storage
Identity and authentication Ledger of transaction Signatures Block-number along with hash
Access control Policy header and transactions in BC Multiset transaction Block-number with hash
Protocol and network Encryption Encryption Encryption
Privacy Not-private PK or ID Block-number along with hash
Trust Predefined Verification Signed hash of data
Nonreputation Encryption Signatures Signed hash of data
Policy enforcement Policy header PK lists Accounting
Authorization Policy header and transactions List of keys Accounting
Fault tolerance Medium High Low
4 Journal of Sensors

83
205
128
107
39
7
0
50
100
150
200
250
2022 2021 2020 2019 2018 2017
No. of documents
Year
No. of documents published by authors per year
(a)
113
74
46
39
36
33
21
20
20
19
17
15
0 20 40 60 80 100 120
India
China
United states
Australia
United kingdom
Saudi arabia
South korea
Canada
United arab emirates
Italy
Egypt
France
Documents
Documents by country (Territory)
Country (Territory)
(b)
Figure 3: Continued.
5Journal of Sensors

cause for this. Despite the fact that most IoT [16] apps have
authentication enabled, there are security concerns that lead
to data loss. Some of the difficulties are as follows. The
authors offer a case study on a smart plug system in which
they effectively exploit protocols and launch attacks such as
brute force, device scanning, firmware assault, and spoofing
attack. Their experiments reveal that they are capable of
gaining the upper hand.
In the importance of authentication in IoT systems [40],
authentication is the cornerstone of providing good security.
In IoT systems and m2m applications, a variety of authenti-
cation mechanisms are used. These authentication proce-
dures are simple and rely on XOR and hash operations to
communicate inside the IoT technology ecosystem [17].
Leakage of critical data is a major concern in many IoT net-
works Munindar P. Singh et al. (2017) and Muhammad
Shahzad et al (2017). The fundamental cause, according to
the authors, is that IoT networks lack authentication proce-
dures. The authors suggest alternative approaches for user
identification and authorization for IoT networks that lack
traditional user interfaces. The authors discuss why authen-
tication is critical in an IoT network. They also [41] provide
a solution for overcoming the lack of a traditional user inter-
face for IOT networks.
The search approach should be thorough and objective,
as well as simple and repeatable. The search is restricted
from 2017 to 2022. The work done on blockchain and Inter-
net of Things integration in the last six years is given below,
as shown in Figures 3(a)–3(c).
This investigation is based on publications found in the
Scopus electronic database. Searching is an important com-
ponent of performing a systematic review. In our search,
we employed terms such as keywords, title, authors, abstract,
references, and index/subject terms, as shown in Figures 4(a)
and 4(b). And historiography and average citation per year
are shown in Tables 2 and 3. Authors have worked on vari-
ous next generation IoT and Blockchain Integration con-
cepts for the last seven years, as shown in Table 4.
Table 2 presented historiography based on clustering in
Figure 4(b).
Blockchain is an ever-growing list of records that are
linked and protected using cryptographic methods. It also
offers its users the flexibility to conduct transactions with
lower costs and faster speeds. This is presented in Table 3
in the form of citations.
4. Blockchain and IoT Integration
IoT is transforming and optimizing manual workflows to
become part of the digital age. By receiving a large amount
of information that provides a level of knowledge that has
never been heard before, this knowledge facilitates the devel-
opment of intelligent applications, such as improving the
management and quality of people’s lives through the digiti-
zation of city services. In the past few years [2], Cloud com-
puting technology has contributed to the IoT’s essential
functions for analysing and processing data and turn them
into real-time actions and knowledge. Unprecedented
growth in the IoT [18] has opened up new opportunities
for communities, such as mechanisms for accessing and
sharing information. The open data paradigm is the primary
guide to these initiatives. However, one of the most impor-
tant vulnerabilities of these initiatives which happened in
many the situation is lack of confidence. A centralized
38%
25%
8%
8%
4%
4%
4%3% 3%3%
Documents by subject area
Computer science
Engineering
Decision sciences
Mathematics
Social sciences
Business, management
and accounting
Physics and astronomy
Energy
(c)
Figure 3: (a) The annual and cumulative numbers of research documents related to blockchain and IoT integration. (b) The country and
cumulative numbers of research documents related to blockchain and IoT integration. (c) The subject area and cumulative numbers of
research documents related to blockchain and IoT integration.
6 Journal of Sensors

architecture like the one used in cloud computing is crucial
to the development of IoT. They act as a black box, and net-
work participants do not have a clear vision of where and
how to use the information they provide.
The integration of promising technologies such as IoT
and cloud computing has proven invaluable. In the same
way, we recognize the enormous potential of blockchain in
revolutionizing the IoT [19]. Blockchain can empower the
IoT by providing reliable sharing services. The information
is reliable and traceable. The source of information can be
identified at any time. And the data will remain unchanged
over time. Improve safety where IoT data should be shared
securely between large numbers of participants. This inte-
gration represents a major revolution. For example, thor-
ough traceability in many food products is a key factor in
ensuring food safety. Food traceability may require the par-
ticipation of a large number of participants: production,
feeding, treatment, distribution, etc. A leak in any part of
the chain could lead to a breach and slows down the process
of finding infections. This can have a devastating impact on
citizens’lives and cause enormous economic costs to compa-
nies, sectors, and countries. In the event of a food-borne out-
break, better controls in these areas would increase food
safety [6, 20], improved sharing of information between par-
ticipants, reduce search time in case of foodborne outbreaks
and saving human lives. In addition, in other areas such as
smart cities and smart cars, trusted sharing of information
can be beneficial to include new participants in the ecosys-
tem and contribute to improving service and acceptance.
Therefore, the use of blockchain can complement the IoT
with reliable and secure data. This became known, as men-
tioned, where blockchain technology was identified as the
DE AU AU_CO
(a)
Centrality
Impact
Internet of things - conf 32.8%
Blockchain - conf 35.7%
Block-chain - conf 29.6%
Internet of things - conf 50.6%
Blockchain - conf 47.6%
Block-chain - conf 46.4%
Internet of things - conf 16.7%
Blockchain - conf 16.7%
Block-chain - conf 24%
(b)
Figure 4: (a) A screenshot of the three fields plot in bibliometric analysis created based on keywords, authors with author’s country. (b)
Clustering by coupling map.
7Journal of Sensors

key to solving scalability problems, privacy and reliability
associated with the IoT paradigm, increased security, trust
and lowering costs were all cited as top benefits of Block-
chain/IoT, as shown in Table 5.
From our perspective, IoT can benefit greatly from
blockchain functionality and will help to develop the current
IoT technology in the future. It is worth noting that there are
still a number of research challenges and open issues that
need to be explored in order to seamlessly integrate these
two technologies, and this research topic is still in its prelim-
inary stages, especially improvements that this integration
can bring (but not limited to):
Decentralization and scalability: the transition from a
centralized architecture to a distributed P2P removes the
center of failure and bottlenecks [21]. It also prevents situa-
tions where few powerful companies control the processing
and storage of many people. Other benefits along with the
decentralization of the architecture is to improve the sys-
tem’s fault tolerance and scalability, and it reduces IoT silos
and contributes to further improvements in IoT scalability.
Identity: using common blockchain participants can
identify every device. The data provided and entered into
the system are immutable and uniquely identifies the actual
data provided by the device. Additionally, the blockchain
can provide distributed authentication and device authoriza-
tion for IoT applications. It will represent improvements in
IoT and participants.
Autonomy: Blockchain technology powers next-
generation application features [22]. This makes it possible
to develop intelligent automated assets and hardware as a
service. With blockchain, devices can interact without
servers involved. IoT applications may benefit from this
functionality in application procurement.
Reliability: IoT data remains immutable and distributed
over time in the blockchain. System participants can verify
the accuracy of the information and ensure that it has not
been tampered with. In addition, this technology allows the
collection and monitoring of sensor data. Trust is an impor-
tant part of the blockchain brought by the IoT.
Security: data and communications can be secured by
storing blockchain transactions. Blockchains can be used to
translate device messages into transactions [23]. Validated
by smart contract, in this way, communication between
devices is secure. Today’s secure standard protocols used in
the IoT can be extended with blockchain applications.
Services market: Blockchain can accelerate the creation
of the IoT ecosystem of services and data markets. There,
transactions between colleagues can be done without
employees, and microservices can easily implement and
make micropayments. It can be done safely in an unreliable
environment. This will improve IoT connectivity and access
to IoT data on the blockchain.
Secure code alignment: uses secure, unmodified block-
chain storage. The code can be secured and securely inserted
into the device [24]. Manufacturers can track status and
update with confidence. IoT middleware can take advantage
of this capability to securely update their IoT devices.
4.1. Blockchain Technology Solution to IoT. The challenges
that IoT systems confront might be solved more effectively
with blockchain technology. The number of interacting items
or devices in IoT systems is likely to expand in the future. As
the number of gadgets increases, they will attempt to commu-
nicate with one another, resulting in the internet becoming a
medium. Because most acquired data in IoT devices is stored
on central servers, this would provide a number of challenges.
If devices wish to access data, they must communicate via a
centralized network, [8] with data flowing through a central
server. Decentralized or dispersed networks with peer-to-
Table 2: Historiography.
Paper Title DOI Year Cluster
Bodkhe, 2020, Trans emerg
telecommun technol Blockchain for precision irrigation: opportunities and challenges 10.1002/ett.4059 2020 1
Li, 2022, Trans emerg
telecommun technol
Blockchain as a service models in the internet of things
management: systematic review 10.1002/ett.4139 2022 1
Khan, 2021, Electronics
(Switzerland) Reliable Internet of Things: challenges and future trends 10.3390/
electronics10192377 2021 2
Guru, 2021, Electronics
(Switzerland)
Approaches towards blockchain innovation: a survey and future
directions
10.3390/
electronics10101219 2021 2
Sadawi, 2021, IEEE access A survey on the integration of blockchain with IoT to enhance
performance and eliminate challenges
10.1109/
ACCESS.2021.3070555 2021 2
Tran, 2021, J network comput
appl
Integrating blockchain and Internet of Things systems: a
systematic review on objectives and designs
10.1016/
j.jnca.2020.102844 2021 3
Alkhateeb, 2022, Sensors Hybrid blockchain platforms for the Internet of Things (IoT): a
systematic literature review 10.3390/s22041304 2022 3
Table 3: Average citation per year.
Year NMeanTCperArt MeanTCperYear CitableYears
2018 18 35.78 8.94 4
2019 35 37.71 12.57 3
2020 40 18.07 9.04 2
2021 63 6.27 6.27 1
2022 42 0.74 0
8 Journal of Sensors

peer networking (PPN), distributed file sharing (DFS), and
autonomous device coordination (ADC) capabilities are one
of the best ways to tackle this [25]. These three roles may be
carried out by blockchain, allowing IoT systems to track a
large number of linked and networked devices. BC enables
IoT systems to coordinate the processing of transactions
between devices. BC will improve the security and dependabil-
ity of IoT systems, making them more resilient. With the sup-
port of a distributed ledger, BC enables for speedier peer-to-
peer communications.
4.2. Blockchain Scalability in IoT. Blockchain has gained
popularity as a result of the use of Bitcoin for online transac-
tions that do not require third-party security. However, the
most difficult challenge for blockchain providers is the scal-
ability. Scalability issues must be addressed to integrate IoT
and blockchain. On the one hand, because of their sheer
number, IoT devices will generate transactions at a rate that
current blockchain [10] solutions will not be able to handle.
However, owing to resource constraints, it is impossible to
implement blockchain peers on IoT devices. Both technolo-
gies cannot directly be integrated in their current state [26].
To address the issue of scalability, various techniques such as
Segwit, Sharding, block size increase, POS, and off-chain
state have been proposed. Segwit, or segregated witness, is
a scalability solution that increases the number of transac-
tions in a block while keeping the block size constant. By
removing the signature data from the Bitcoin transaction, a
segregated witness creates room for new transactions.
Biswas et al. proposed a framework that enables the block-
chain ledger to scale across all peers by establishing a local peer
network. It limited the number of transactions that enter the
global blockchain by implementing a scalable local ledger
while maintaining peer validation of transactions at both the
local and global levels. The results of the implementation
testbed showed that significant improvements in the
Table 4: Authors have worked on various IoT and Blockchain Integration concepts for the last seven years.
References Year Objectives Future scope
[16] 2016
IoT middleware, cloud platforms, and cloud infrastructures
are all surveyed as integration components. Additionally,
certain integration ideas and data analytics methods are
reviewed, along with various difficulties and unresolved
research problems.
Users can choose the essential components depending on
their own needs in order to achieve a smooth integration
based on the comparisons performed and the aspects
examined.
[29] 2017
A test bed is described to compare central and local data
processing and highlight benefits of distributing data
across multiple locations in a network.
Using test bed, this system offers network saving, real-time
processing, intelligent local data processing, and potential
local processing mechanisms within the smart grid.
[30] 2018
It discusses several application areas, groups the literature
that is now available into these categories, introduces two
usage patterns—device manipulation and data
management, and provides information on the stage of
development of some of the solutions currently available.
The machine economy was created as a result of attempts
to commercialise data due to the prevalence of IoT devices
and rising data creation. The use of BC to address the issue
of data trading and interchange is an example of how this
could be applied in the real world.
[34] 2019
Implementation of five privacy-preserving techniques,
including privacy protection, encoding, private enterprises,
combining, and discrepancy secrecy, in blockchain-based
IoT systems.
Before being put into use, blockchain-based IoT devices
need to be protected against a number of privacy issues.
[36] 2020 A case study is implemented in a smart IoT system
utilizing the Ethereum-based Blockchain technology.
The IoT smart environment is created using sensor devices,
and on the Ethereum platform, devices are authorised
using the Dec AUTH protocol.
[40] 2021 The suggested BaaU-based framework for trustworthiness
in the HIoT systems of the future.
Next-generation healthcare IoT (HIoT) applications may
be one of the industries that the blockchain network will
likely revolutionize as a technical improvement.
[41] 2022
A cooperative data sharing system where numerous data
sources and consumers work together to complete data
sharing tasks using cloud-edge computing and blockchain
technology.
The outcomes demonstrated that it can be helpful in
examining the effectiveness of any blockchain-enabled data
sharing system. This will facilitate the successful
implementation of efficient data exchange systems.
Table 5: Benefit of implementing integrated IoT with Blockchain networks.
Benefits 1
St
choice 2
nd
choice Sum
Increased security and trust in shared multiparty transactions and data 33% 30% 63%
Increase in business efficiency and lowering costs 27% 29% 56%
Increase in revenue and business opportunities 21% 22% 43%
Improved constituent or participant experiences 19% 17% 37%
9Journal of Sensors

transaction rate and ledger weight were possible. This would
improve the scalability of large-scale business transactions in
IoT [27] and address the issue of memory requirements for
storing blocks. However, the current implementation and
evaluation have been carried out in part on virtual machines,
with the application written in Node-red.
There are several fields that deploy IoT systems for all
the advantage that it provides such as the ability to capture
the data and communicate with its peer devices without
any human or machine intervention. During these interac-
tions, there is a high possibility of the data leakage. In order
to overcome this, there are various methods that are
employed to address this area of security.
4.3. Importance of Combining IoT with Blockchain. For
industries, IIoT (Industrial Internet of Things) [14] [28] is
an inseparable part. Here, people are made mandate for
delivering IIoT systems that are secure, general, and scalable.
Due to problems like malicious attacks and single point of
failure, the existing IIoT systems are unstable in providing
services. Although blockchain is a technology that has qual-
ities like security promise and recovery combing IoT, and
blockchain is interesting. Most of the IoT devices are power
constrained and are not suitable for blockchain though it has
low-throughput and less power-intensive. For the purpose of
protecting the sensitive data confidentiality, authors came up
with a method that regulates the access to sensor data.
In a centralized architecture, there are problems associ-
ated with obstacles and the center of failure. Moving to a
peer-to-peer architecture solves this problem. Because the
storage space is decentralized, small businesses can control
and process the data, unlike a centralized architecture where
large businesses can control the data [22]. This allows for
better fault tolerance and system scalability. The identity of
the connected device is important because it can lead to
security and reliability issues. All connected devices can be
uniquely identified through a single blockchain system. Cre-
dentials are also required to identify the data that devices
receive. Blockchain also provides authentication for IoT
devices.
Many standalone smart devices can be made using block-
chain technology, which enables advancedfunctionstobeinte-
grated into smart hardware. Smart devices can also interact with
each other without an IoT server. It can be used for modular
applications. The system is also reliable as there is no risk of data
loss from the blockchain. Users can verify data integrity, and
data will remain intact. The system can track and account for
data, so reliability is an important factor in integration consid-
erations [15]. The system is also secure as the data is stored as
blockchain transactions. This allows you to change the type of
transactions monitored by smart contracts. A secure key can
be provided to be securely embedded into IoT devices, allowing
organizations to secretly track and update devices. It can also
create an environment conducive to market exploitation [29].
Transactions between different actors can be done without an
agency, and micropayments can be made instantly even if there
is no trust between different people. It can improve IoT by pro-
viding more blockchain insights.
When integrating a blockchain, it is important to con-
sider whether the devices in the system can interact with
each other. A new layer known as fog computing has been
added between IoT devices and cloud computing for better
integration. Blockchain technology has the following advan-
tages for large scale IoT systems, as shown in Figure 5.
Communication between two IoT devices is fast and
secure. They can also work offline and have the ability to
communicate with each other using routing techniques, so
they do not need a blockchain to communicate. Only a small
amount of data is stored in the blockchain. It is used in
applications that require minimal delay [30], on the other
hand, for communication between the IoT and the block-
chain, all data recording all interactions that occur must pass
through the blockchain. This ensures that all interactions
can be tracked and recorded. In effect, this increases band-
width usage. Therefore, this can be considered as a major
limitation of blockchain. When communicating with hybrid
technologies, small units of information are shared with the
blockchain. Although the IoT [31] connection is direct, it is
difficult to choose which interventions must be carried out
during operation by the blockchain. Fog computing, which
Tamper proof
data
Trustless &
P2P msg.
possibility
Robust Highly
reliable
Cost
reduction
Elimination of
single control
authority
Records
historic action
More private
data
Accelerate
transactions Built in trust Distributed le
sharing
Permits self-
directed
functioning
Figure 5: Blockchain technology have the following advantages for large scale IoT systems.
10 Journal of Sensors

uses gateways and other devices for mining, has overcome
these limitations, but the use of this technology is growing
rapidly. But it is not necessary to use it everywhere. It should
only be used for required applications. In general, private use
of blockchain may not be suitable for applications that
require high performance. However, hybrid techniques
may be required to increase efficiency. Wust and Gervais
introduced a process that identifies blockchain requirements
based on their application.
To facilitate the integration of IoT and blockchain, major
companies are teaming up and selling off-the-shelf devices
[32]. Some IoT devices are sold with built-in functionality
to connect to the EthEmbeddedblockchain, and the com-
pany responsible for Ethereum allows nodes to be installed
on devices such as Odroid, Beaglebone, and Raspberry Pi.
Configure Bitcoins, Litecoins, and Ethereum nodes in the
Raspberry PI a. The RaspnodeWiFi Router also supports
wallet support for Litecoin and Bitcoin. The R-LTC Anrou-
ter can also mine Litecoin, which makes this router easy to
set up. It is still in its infancy and requires extensive research
for further integration. Some IoT devices also have mining
capabilities. Not all IoT devices have this capability. Since
it requires high-quality hardware and is not valid on IoT
devices, you will generally not find mining with IoT.
There are other ways to integrate blockchain with the
IoT, including integration with cloud computing. Devices
have been integrated in this way for many years to address
IoT shortcomings such as storage, access, and compute,
but cloud computing operates in a centralized framework.
It is therefore unreliable and secure when information is
shared with specific recipients. Therefore, blockchain is pre-
ferred over cloud computing to solve this problem.
4.4. Blockchain Used Because of Its Decentralized Nature in
Various Applications. The scattered nature of IoT networks
and their huge scale, according to several academics, is a
big concern, as shown in Figure 6. Even though, the Decen-
tralized nature of blockchain techniques provide privacy and
security, they are not ideal for devices with limited resources
due to delays, considerable energy use, and computational
overhead. These elements define the smart home tier’s dif-
ferent key functions and components [33]. A component
called miner is used to handle the home writers’internal
and external communications. This component is a high-
resource gadget that is always online. Auditing and manag-
ing communications are two more responsibilities of the
miner. Blockchains retain security goals such as integrity,
availability, and secrecy. Because of the different security
threats that have been put on the global IoT network, the
advantages that may be derived from IoT networks may
exceed the risks. Data stored on the central server is subject
to DDoS and Sybil attacks, as well as single point failure,
which reduces the availability of services and exposes the
sensor data stored in the data center.
4.4.1. Potential of Smart Contracts (SC) in Blockchain. SC are
well suited for business activities that involve purchase or
exchange of goods, services, and rights, especially when fre-
quent transactions occur among a network of parties and
manual tasks are performed by counterparties for each
transaction [2]. This application is a match for many finan-
cial services transactions (e.g., simplifying automatic divi-
dend payments, stock splits and cryptographic signatures
on stock certificates, and streamlining over-the-counter
agreements). It also [41] describes many supply chain,
manufacturing, and retail transactions. However, the tech-
nology is still in its infancy, so most use cases of smart con-
tracts today consist of the transfer of cryptocurrency [34]
and recording/changing ownership of land or other assets.
4.4.2. Could Blockchain Technology Can Be a Remedy? Yes.
The blockchain technology could be one of the remedies
for addressing the security and privacy issues in IoT. This
is because, the blockchain technology eliminates the central
server concept of IoT and allows the data to flow through
the blockchain distributed ledger for each transaction with
appropriate authentication.
0
Architecture
Cryptography
Transaction management
Encryption
Dierential privacy
Private contract
Mixing
Consensus mechanism
Access management
Multi-packet transactions
Timestamp obfuscation
10
20
30
40
50
60
Blockchain technology applications in IoT
Blockchain usage
Figure 6: Application types.
11Journal of Sensors

5. Challenges
Storage capacity and scalability—it is still debatable whether
blockchain scalability and storage capacity issues are wide-
spread. And in combination with IoT applications, it
becomes even more difficult. However, for this reason,
Blockchain technology may seem unsuitable for IoT, but
the challenges involved can be avoided or completely mini-
mized: some IoT devices can generate large amounts of data
[18] [35]. This makes integration difficult. This is because
the ubiquitous blockchain cannot handle such large transac-
tions. Therefore, it is beneficial to address these issues before
combining the two technologies. Today, only a small per-
centage of IoT big data is useful for knowledge extraction
and production operations. Therefore, many researchers
have proposed filtering methods. Normalize and compress
IoT data to reduce it. IoT includes devices such as embedded
devices and communication devices. This stores the amount
of data that the IoT provides to the blockchain. Data com-
pression can reduce the data we transmit, process, and store
from the IoT. Finally, negotiated protocols can be used to
increase allocated bandwidth and reduce contract latency.
This improves the integration between IoT and blockchain.
Security by insufficient efficiency and a large number of
uneven devices—security challenges in IoT applications
need to be addressed at different levels. Moreover, IoT
environments have various characteristics such as wireless
communication, mobility, etc. that compound security chal-
lenges. A full security analysis has been performed. It is
important to build a highly secure IoT. Due to the increasing
number of attacks and their severe impact, blockchain is con-
sidered the crucial technology to support much-needed secu-
rity advancements in IoT, but the integrity of data generated
by IoT [9] remains a major challenge. By integrating the two
technologies, blockchain can ensure that the data transmit-
ted through the chain remains intact and changes can be
detected. Therefore, when the data reaches its destination,
the corrupted data stays that way. Apart from suspicious
sources, corrupted data in IoT [36] can come from many
other sources. Factors such as disturbance, device failure,
environment, and type of participant play a role in the
integrity of the IoT framework. Sometimes, IoT devices do
not perform well and are difficult to detect until they are
properly secured. Sometimes, it works fine at first and
works due to hardware or software issues. Eavesdropping,
throttling, or denial of service (DOS) is a major threat that
can have a huge impact on the IoT and therefore needs to
be addressed. Test it properly before combining it. They
must be properly positioned and packaged to avoid physical
damage and include an instant device error detection
mechanism.
Cost and energy—Blockchain adoption is hampered by a
lack of processing capacity. For example, Bitcoin mining
necessitates a significant degree of energy to verify and vali-
date exchanges.
Complexity and inactivity—due to the proprietary
nature of blockchain-based trades, it may take several
hours for all gatherings to update their corresponding
records.
Adoption and mindfulness—the lack of attention and
reception is one of the most fundamental challenges in
blockchain innovation. Many people, for example, have a
limited understanding of how it works.
Limitation of capacity and adaptation—as previously
said, the storage limit and adaptability of blockchain are still
being debated, however, when it comes to IoT applications,
the inherent limit and versatility constraints exacerbate these
issues. In this respect, blockchain may appear to be unsuit-
able for IoT applications [37]; however, there are ways to
alleviate or avoid these limitations. This constraint addresses
a significant barrier to blockchain integration in the IoT,
where devices can continuously generate terabytes (GBs) of
data. It has been discovered that several existing blockchain
operations can only handle a few transactions per second,
which could be a bottleneck for the IoT.
Confidentiality and information security—many IoT appli-
cations operate with private information, such as when a device
is attached to an individual, as in the e-healthcare situation,
thus, it is critical to solve the issue of data security and anonym-
ity. Although Blockchain is touted as the greatest solution for
addressing the personalities of IoT [38–41] leaders, there may
be applications where anonymity is required, similar to Bitcoin.
This is the case with a wearable that can hide an individual’s
identity when delivering personal information, or with clever
cars that preserve the security of customers’schedules.
Brilliant agreements—although brilliant agreements
have been identified as the ideal application of blockchain
innovation, there are still a few issues to be resolved, as pre-
viously said. The use of clever contracts in IoT [42–44]
might be beneficial, but the way they integrate into IoT
applications is different [45, 46].
6. Conclusion and Future Scope
Blockchain aims to revolutionize the next generation IoT.
This review has provided a comprehensive overview of the
interaction between blockchain technology and the IoT
model. Implementing restrictions is important for integrat-
ing blockchain and IoT into government infrastructure. This
recognition will accelerate engagement between citizens,
governments, and businesses. Consensus will play an impor-
tant role in integrating IoT as part of the process of mining
and distributing more blockchains. Research efforts should
be made to ensure the security and privacy of key technolo-
gies such as IoT and blockchain. One of the biggest concerns
about blockchain is that people are taking advantage of this
situation, especially in the context of the instability of digital
currency. The paper then also went on to explain and chro-
nologically introduce articles on Internet of Things, IoT
security using blockchain, Blockchain scalability in IoT,
and new challenges and opportunities in IoT and defense
mechanisms, as well as using blockchain to ensure confiden-
tiality, authentication, access control, trust, and reputation.
Although enabling IoT data security, blockchain has numer-
ous significant problems. For a successful blockchain and
IoT integration, an analysis of the key problems of block-
chain and IoT integration should be investigated, consider-
ing the issues raised in this study. As future work, we
12 Journal of Sensors

intend to investigate how blockchain, edge computing, and
IoT can complement each other in their integration, as well
as how edge computing’s many security and data integrity
issues may be handled by using blockchain technology.
Finally, we intend to launch a variety of blockchain applica-
tions in the IoT because of blockchain’s autonomy to foster
the creation of next generation IoT markets. The whole
prospect of working on blockchain to maybe one day create
something that has never been done before is the motivation
behind trying to make this decentralized app.
Data Availability
No data were used to support this study.
Conflicts of Interest
We declared no competing interest exists.
Acknowledgments
The authors would like to acknowledge the support of Prince
Sultan University for paying the Article Processing Charges
(APC) of this publication.
References
[1] S. N. Khan, F. Loukil, C. Ghedira-Guegan, E. Benkhelifa, and
A. Bani-Hani, “Blockchain smart contracts: applications, chal-
lenges, and future trends,”Peer-to-peer Networking and Appli-
cations, vol. 14, no. 5, pp. 2901–2925, 2021.
[2] C. McPhee and A. Ljutic, “Editorial: Blockchain,”Manage-
ment Review, vol. 7, no. 10, pp. 3–5, 2017.
[3] A. Angrish, B. Craver, M. Hasan, and B. Starly, “A case study
for Blockchain in manufacturing: "FabRec": a prototype for
peer- to-peer network of manufacturing nodes,”Procedia
Manufacturing, vol. 26, pp. 1180–1192, 2018.
[4] T. Justinia, “Blockchain technologies: opportunities for solving
real-world problems in healthcare and biomedical sciences,”
Acta Informatica Medica, vol. 27, no. 4, pp. 284–291, 2019.
[5] M. Andoni, V. Robu, D. Flynn et al., “Blockchain technology in
the energy sector: a systematic review of challenges and oppor-
tunities,”Renewable and Sustainable Energy Reviews, vol. 100,
pp. 143–174, 2019.
[6] M. Alharby and A. Van Moorsel, “Blockchain-based smart
contracts: a systematic mapping study,”2017, http://arxiv
.org/abs/1710.06372.
[7] M. Iansiti and K. R. Lakhani, “Harvard Business Review,”
HBR, R1701J, Jan-Feb, 2017.
[8] I. Karamitsos, M. Papadaki, and N. B. Al Barghuthi, “Design of
the blockchain smart contract: a use case for real estate,”Jour-
nal of Information Security, vol. 9, no. 3, pp. 177–190, 2018.
[9] S. Nakamoto, “Bitcoin whitepaper,”vol. 17, no. 7, p. 2019,
2008, URL: https://bitcoin.org/bitcoin.pdf-.
[10] Z. Wang, H. Jin, W. Dai, K. K. R. Choo, and D. Zou, “Ether-
eum smart contract security research: survey and future
research opportunities,”Frontiers of Computer Science,
vol. 15, no. 2, pp. 1–18, 2021.
[11] A. H. Mohammed, A. A. Abdulateef, and I. A. Abdulateef,
“Hyperledger, Ethereum and blockchain technology: a short
overview,”in 2021 3rd International Congress on Human-
Computer Interaction, Optimization and Robotic Applications
(HORA), pp. 1–6, Ankara, Turkey, 2021.
[12] H. Xiaoting and N. Li, “Subject information integration of
higher education institutions in the context of Web3. 0,”in
2010 The 2nd International Conference on Industrial Mechatro-
nics and Automation,vol.2,pp.170–173, Wuhan, China, 2010.
[13] M. Hamilton, “Blockchain distributed ledger technology: an
introduction and focus on smart contracts,”Journal of Corpo-
rate Accounting & Finance, vol. 31, no. 2, pp. 7–12, 2020.
[14] W. Metcalfe, Ethereum, Smart Contracts, DApps, Blockchain
and Crypt Currency, 2020.
[15] E. Mik, “Smart contracts: terminology, technical limitations
and real world complexity,”Law, Innovation and Technology,
vol. 9, no. 2, pp. 269–300, 2017.
[16] M. Díaz, C. Martín, and B. Rubio, “State-of-the-art, challenges,
and open issues in the integration of internet of things and
cloud computing,”Journal of Network and Computer Applica-
tions, vol. 67, pp. 99–117, 2016.
[17] J. Rivera and R. Van Der Meulen, “Gartner,”Forecast Alert:
Internet of Things—Endpoints and Associated Services, World-
wide, Gartner, Ed., 2016.
[18] K. Zīle and R. Strazdiņa, “Blockchain use cases and their feasi-
bility,”Applied Computer Systems, vol. 23, no. 1, pp. 12–20,
2018.
[19] M. A. Engelhardt, “Hitching healthcare to the chain: an intro-
duction to blockchain technology in the healthcare sector,”
Technology Innovation Management Review, vol. 7, no. 10,
pp. 22–34, 2017.
[20] S. Nakamoto, “Bitcoin: a peer-to-peer electronic cash system,”
Decentralized Business Review, p. 21260, 2008.
[21] A. M. Antonopoulos, Mastering Bitcoin: Unlocking Digital
Cryptocurrencies, O'Reilly Media, Inc., 2014.
[22] Z. Zheng, S. Xie, H. N. Dai, X. Chen, and H. WangBlockchain
challenges and opportunities: a survey,”International Journal of
Web and Grid Services,vol.14,no.4,pp.352–375, 2018.
[23] N. Radziwill, “Blockchain revolution: how the technology
behind bitcoin is changing money, business, and the world,”
The Quality Management Journal, vol. 25, no. 1, pp. 64-65,
2018.
[24] E. Androulaki, A. Barger, V. Bortnikov et al., “Hyperledger
fabric: a distributed operating system for permissioned block-
chains,”in Proceedings of the thirteenth EuroSys conference,
pp. 1–15, 2018.
[25] J. Kennedy, “$1.4 bn investment in blockchain start-ups in last
9 months, says PwC expert,”Silicon.com, vol. 4, 2016.
[26] I. Eyal, A. E. Gencer, E. G. Sirer, and R. Van Renesse, “{Bit-
coin-NG}: a scalable blockchain protocol,”in 13th USENIX
symposium on networked systems design and implementation
(NSDI 16), pp. 45–59, 2016.
[27] N. M. Kumar and P. K. Mallick, “Blockchain technology for
security issues and challenges in IoT,”Procedia Computer Sci-
ence, vol. 132, pp. 1815–1823, 2018.
[28] J. Bhosale and S. Mavale, “Volatility of select crypto-curren-
cies: a comparison of Bitcoin, Ethereum and Litecoin,”Annual
Research Journal of SCMS Pune, vol. 6, 2018.
[29] U. Ahsan and A. Bais, “Distributed big data management in
smart grid,”in 2017 26th Wireless and Optical Communication
Conference (WOCC), pp. 1–6, Newark, NJ, USA, 2017.
[30] A. Panarello, N. Tapas, G. Merlino, F. Longo, and A. Puliafito,
“Blockchain and iot integration: a systematic survey,”Sensors,
vol. 18, no. 8, p. 2575, 2018.
13Journal of Sensors

[31] A. Reyna, C. Martín, J. Chen, E. Soler, and M. Díaz, “On block-
chain and its integration with IoT. Challenges and opportunities,”
Future Generation Computer Systems,vol.88,pp.173–190, 2018.
[32] H. F. Atlam, M. A. Azad, A. G. Alzahrani, and G. Wills, “A
review of blockchain in internet of things and AI,”Big Data
and Cognitive Computing, vol. 4, no. 4, p. 28, 2020.
[33] C. Nartey, E. T. Tchao, J. D. Gadze et al., “On blockchain and
IoT integration platforms: current implementation challenges
and future perspectives,”Wireless Communications and
Mobile Computing, vol. 2021, 25 pages, 2021.
[34] M. U. Hassan, M. H. Rehmani, and J. Chen, “Privacy preserva-
tion in blockchain based IoT systems: integration issues, pros-
pects, challenges, and future research directions,”Future
Generation Computer Systems, vol. 97, pp. 512–529, 2019.
[35] A. Al Sadawi, M. S. Hassan, and M. Ndiaye, “A survey on the
integration of blockchain with IoT to enhance performance
and eliminate challenges,”IEEE Access, vol. 9, pp. 54478–
54497, 2021.
[36] B. K. Mohanta, D. Jena, S. Ramasubbareddy, M. Daneshmand,
and A. H. Gandomi, “Addressing security and privacy issues of
IoT using blockchain technology,”IEEE Internet of Things
Journal, vol. 8, no. 2, pp. 881–888, 2021.
[37] E. A. Shammar, A. T. Zahary, and A. A. Al-Shargabi, “A survey
of IoT and blockchain integration: security perspective,”IEEE
Access, vol. 9, pp. 156114–156150, 2021.
[38] S. K. Lo, Y. Liu, S. Y. Chia et al., “Analysis of blockchain solu-
tions for IoT: a systematic literature review,”IEEE Access,
vol. 7, pp. 58822–58835, 2019.
[39] T. Alam, “Blockchain and its role in the internet of things
(IoT),”International Journal of Scientific Research in Com-
puter Science, Engineering and Information Technology,
vol. 5, no. 1, pp. 151–157, 2019.
[40] A. O. Almagrabi, R. Ali, D. Alghazzawi, A. AlBarakati, and
T. Khurshaid, “Blockchain-as-a-utility for next-generation
healthcare internet of things,”CMC-Computers Materials &
Continua, vol. 68, no. 1, pp. 359–376, 2021.
[41] M. M. Mijwil, K. Aggarwal, D. S. Mutar, N. Mansour, and R. S.
Singh, “The position of artificial intelligence in the future of
education: an overview,”Journal of Applied Sciences, vol. 10,
no. 2, 2022.
[42] S. D. Okegbile, J. Cai, and A. S. Alfa, “Performance analysis of
blockchain-enabled data sharing scheme in cloud-edge
computing-based IoT networks,”IEEE Internet of Things Jour-
nal, 2022.
[43] A. Alsharef, K. Aggarwal, M. Kumar, and A. Mishra, “Review
of ML and AutoML solutions to forecast time-series data,”
Archives of Computational Methods in Engineering, pp. 1–15,
2022.
[44] L. Kakkar, D. Gupta, S. Saxena, and S. Tanwar, “IoT architec-
tures and its security: a review,”in Proceedings of the Second
International Conference on Information Management and
Machine Intelligence, pp. 87–94, Springer, Singapore, 2021.
[45] M. M. Mijwil, D. S. Mutar, Y. Filali, K. Aggarwal, and H. Al-
Shahwani, “Comparison between expert systems, machine
learning, and big data: an overview,”Journal of Applied Sci-
ences, vol. 10, no. 1, 2022.
[46] S. Tanwar, T. Paul, K. Singh, M. Joshi, and A. Rana, “Classifi-
cation and imapct of cyber threats in India: a review,”in 2020
8th International Conference on Reliability, Infocom Technolo-
gies and Optimization (Trends and Future Directions)(I-
CRITO), pp. 129–135, Noida, India, 2020.
14 Journal of Sensors