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Blockchain for Industry 4.0: A Comprehensive Review

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Due to the proliferation of ICT during the last few decades, there is an exponential increase in the usage of various smart applications such as smart farming, smart healthcare, supply-chain & logistics, business, tourism and hospitality, energy management, etc. However, for all the aforementioned applications, security and privacy are major concerns keeping in view of the usage of the open channel, i.e., the Internet for data transfer. Although many security solutions and standards have been proposed over the years to enhance the security levels of the aforementioned smart applications, the existing solutions are either based upon centralized architecture (having a single point of failure) or having high computation and communication costs. Moreover, most of the existing security solutions have focussed only on a few aspects and fail to address scalability, robustness, data storage, network latency, auditability, immutability, and traceability. To handle the aforementioned issues, blockchain technology can be one of the solutions. Motivated from these facts, in this paper, we present a systematic review of various blockchain-based solutions and their applicability in various Industry 4.0-based applications. Our contributions in this paper are four fold. Firstly, we explored the current state-of-the-art solutions in the blockchain technology for smart applications. Then, we illustrated the reference architecture used for the blockchain applicability in various Industry 4.0 applications. Then, the merits and demerits of the traditional security solutions are also discussed in comparison to their countermeasures. Finally, we provided a comparison of existing blockchain-based security solutions using various parameters to provide deep insights to the readers about its applicability in various applications.
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Blockchain for Industry 4.0: A
Comprehensive Review
UMESH BODKHE1, SUDEEP TANWAR1, KARAN PAREKH1, PIMAL KHANPARA1,
SUDHANSHU TYAGI2, NEERAJ KUMAR3, MAMOUN ALAZAB4
1Department of Computer Science and Engineering, Institute of Technology, Nirma University, Ahmedabad, Gujarat, India (e-mails:
umesh.bodkhe@nirmauni.ac.in, sudeep.tanwar@nirmauni.ac.in, 17mcen16@nirmauni.ac.in, pimal.khanpara@nirmauni.ac.in)
2Department of ECE, Thapar Institute of Engineering and Technology, Deemed to be University, Patiala, Punjab (e-mail: sudhanshutyagi123@gmail.com)
3Department of CSE, Thapar Institute of Engineering and Technology, Deemed to be University, Patiala, Punjab, India and Department of Computer Science and
Information Engineering, Asia University, Taiwan (email: neeraj.kumar@thapar.edu)
4College of Engineering, IT & Environment, Charles Darwin University, Casuarina, NT 0810, Australia. (email: mamoun.alazab@cdu.edu.au)
Corresponding author: Mamoun Alazab (mamoun.alazab@cdu.edu.au), Neeraj Kumar (neeraj.kumar@thapar.edu.in).
This work was supported by the Department of Corporate and Information Services, NTG of Australia.
ABSTRACT Due to the proliferation of ICT during the last few decades, there is an exponential increase
in the usage of various smart applications such as smart farming, smart healthcare, supply-chain & logistics,
business, tourism and hospitality, energy management etc. However, for all the aforementioned applications,
security and privacy are major concerns keeping in view of the usage of the open channel, i.e., Internet for
data transfer. Although many security solutions and standards have been proposed over the years to enhance
the security levels of aforementioned smart applications, but the existing solutions are either based upon
the centralized architecture (having single point of failure) or having high computation and communication
costs. Moreover, most of the existing security solutions have focussed only on few aspects and fail to address
scalability, robustness, data storage, network latency, auditability, immutability, and traceability. To handle
the aforementioned issues, blockchain technology can be one of the solutions. Motivated from these facts,
in this paper, we present a systematic review of various blockchain-based solutions and their applicability
in various Industry 4.0-based applications. Our contributions in this paper are in four fold. Firstly, we
explored the current state-of-the-art solutions in the blockchain technology for the smart applications.
Then, we illustrated the reference architecture used for the blockchain applicability in various Industry
4.0 applications. Then, merits and demerits of the traditional security solutions are also discussed in
comparison to their countermeasures. Finally, we provided a comparison of existing blockchain-based
security solutions using various parameters to provide deep insights to the readers about its applicability
in various applications.
INDEX TERMS Blockchain, Consensus algorithms, Cyber-physical systems, IoT, Smart Grid, Supply
Chain Management, Intelligent Transportation.
I. INTRODUCTION
WIth the wide popularity of Internet and related tech-
nologies, various Industry 4.0-based applications
have been used across the globe in which sensors and actu-
ators sense, compute and communicate the data for industry
automation. As in Industry 4.0-based applications, data be-
tween different locations flows using an open channel, i.e.,
Internet, so threats to security and privacy has also increased
manyfold [1]. Such applications deal with data in large vol-
umes and hence, so it is necessary to consider issues such
as-data heterogeneity, data integrity, and data redundancy
alongwith the security and privacy concerns. Moreover, dif-
ferent applications require datasets from different domains in
different formats. Therefore, it is also needed to standardize
the data format so that it can be used by different Industry
4.0-based applications.
The usage of smart phones and smart applications for
personal, professional, and social activities is increasing ex-
ponentially across the globe. It results an increase in both
the network data traffic (in GBs) and overall expenditure
(in Billions USD) as shown in Fig. 1(a) and (b) as per the
report mentioned in [2], [3]. According to this report, smart
industries would spend $40B on IoT by 2020 in various sec-
tors including transportation and manufacturing. However,
VOLUME 4, 2016 1
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This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
due to the large number of data exchanges over the Internet,
maintaining confidentiality, privacy, and integrity becomes a
major issue in Industry 4.0 [4]. Moreover, according to the
surveys conducted by different agencies [5], [6]nearly 60
millions people are affected by identity theft and 12 billion
peoples records misused in 2018 and expected to increase to
33 billion by 2023 as shown in Fig. 2(a). Fig. 2(b) shows the
10 recent security breaches incidents reported till July 2018,
which are expected to increase in the years to come.
Security and privacy preservation are important concerns
for Industry 4.0 applications [4] [7]. There may be chances of
unauthorized data breaching or information leakage leading
to the financial losses to Industry 4.0-based applications. In
the absence of robust security architecture, the system along
with data are prone to various types of attacks (such as
DDoS, ARP spoofing attacks, data rate alteration, network
congestion, manipulation, noise interference, phishing and
config threats) which can harm the confidentiality and in-
tegrity of data and can affect the overall functioning of any
system. For such types of attacks, prevention is better than
any reactive defense mechanisms to assure confidentiality,
integrity, and privacy within the legal compliance rules [8].
It has been found in the literature that with an increasing rate
of automation in Industry 4.0., the probability of violating
the security rules and launching new type of cyber-attacks
is also increasing. Access control, authorization, confiden-
tiality, availability, and integrity are the prime concerns in
Industry 4.0.
To mitigate the aforementioned threats, current Industry
solutions are using the centralized, client-server based ar-
chitecture in which the centralized authority holds all the
privileges. But, if the centralized authority is compromised
then the entire system may crash. Conventional security
mechanisms such as Data Encryption Standard (DES), and
Advanced Encryption Standard (AES) and their variants are
also being used but they have high computation and commu-
nication overhead. However, a revolution in this area came
with the introduction of the concept of "Bitcoins" [9]. For
example, Authors of [10] illustrated that how blockchain
technology can be used to deal with privacy & security issues
in Industry 4.0 [11].
The blockchain technology has the potential to handle
various security attacks as it can eliminate the need of the
centralized authority to perform various operations. In the
blockchain technology, a number of users participate in trans-
action verification and validation [12]–[17]. It uses a struc-
tural distributed database which stores data from all the nodes
in an encrypted form validated using various checks such as
Merkle hash tree (MHT) and Elliptical Curve Cryptography
(ECC) [17]. As the database is distributed, so there is a risk of
getting crashed or corrupted. Transactions are linked together
with cryptographic keys and immutable ledgers which makes
it difficult for attackers to manipulate or delete the recorded
information. Data is always stored in an immutable manner
using timestamps, public audit and consensus mechanisms
[18], [19]. The use of these mechanisms makes security
architecture a robust and assures data integrity and privacy
[20].
A. SCOPE OF THIS SURVEY ARTICLE
The blockchain reduces the risk of single point of failure
and network attacks using the distributed network nodes.
Use of the decentralized platform reduces fraud by time
stamping entries, and information of users is stored in im-
mutable ledger across the network using the smart contact.
Blockchain eliminates manual processes like reconciliation
between multiple isolated ledger and administrative pro-
cesses which helps to reduce the cost of the system. Due
to the use of various cryptographic linked chains, the speed
of transaction and level of security is enhanced manyfold.
Several surveys are conducted by the researchers using the
blockchain technology for Industry 4.0 which are summa-
rized as follows [21].
Mettler et al. [22] explored how blockchain technology
revolutionized the healthcare alongwith various open chal-
lenges [23], [24]. Huumo et al. [25] reviewed the current
scenario of the blockchain technology and its research gaps
and challenges. They have also discussed the suitability of
the blockchain for various smart applications. Ahram et al.
[26] discussed the various components in blockchains such
as decentralized techniques and immutability of ledger that
makes it difficult to attack the system [27].
Weiss et al. [28] discussed about blockchain public
healthcare applications. They have also explored how the
blockchain technology eliminates the centralized authority
during the verification process, its digital signatures [29] for
safe data repository, its architecture, and also the challenges.
Zhang et al. [30] evaluated the metrics of blockchain-based
decentralized applications. In this paper, they considered
the evolution metrics, security, and challenges which are
important for various applications like healthcare, smart-
agriculture, IoT, and tourism & hospitality. Liu et al. [31]
explored an advanced blockchain architecture for the elec-
tronic health systems. They focused on the regulatory com-
pliance for the data privacy of blockchain, its architecture,
limitations, and benefits [32]. Duan et al. [33] explored
educational applications of the blockchain technology. In
this paper, an automated evaluation software as a tool with
blocks is proposed, which contains graduation marks along
with the certificate. They also highlighted how blocks are
recorded, Merkle hash tree, hash functions, digital signatures,
and timestamp mechanisms during the verification of various
transactions.
Radanovic et al. [34] explored the opportunity of applying
blockchain technology in the medical domain. Authors fo-
cused on the areas such as supply-chain of drugs, pharmaceu-
ticals, and health insurance with associated challenges. They
also discussed how the blockchain can be used in countries
like USA and India for the land registration. Vujicic et al.
[35] gave an overview of blockchain bitcoin and Etheruem
cryptocurrency platforms. In this paper, the authors explained
the architecture, security parameters, and challenges for im-
2VOLUME 4, 2016
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This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI
10.1109/ACCESS.2020.2988579, IEEE Access
Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
FIGURE 1: Statistics of (a) Data traffic per month region wise and (b) Application-wise expenditure on Industry 4.0
FIGURE 2: (a) Increase in identity theft and (b) Generation of data traffic
plementation of blockchain in various applications.
Chen et al. [36] discussed the tokenization of money that
uses the blockchain. In this paper, the working of the token
and their types such as token, initial coin offering, and its cur-
rency are discussed. Gatteschi et al. [37] explained whether
the adoption of the blockchain in different industries can
improve their productivity. Authors showed the blockchains
has been used in various smart applications. Authors also
described the functionality, architecture, techniques used, se-
curity parameters, and open research areas. Nallapaneni et al.
[38] explored the blockchain security, issues and challenges
in IoT systems. They discussed various existing security
and privacy issues related to IoT devices and the possible
solutions by the adoption of blockchain technology [39]–
[41]. Konstantinidis et al. [42] presented various blockchain-
based smart business applications.
From the above-mentioned proposals, we found that most
of the recent surveys on the blockchain technology have
concentrated on various smart application areas in Industry
4.0 and its security parameters [43], [44]. The comparative
analysis of pre-existing surveys on Blockchain with the pro-
posed survey is given in Table 1.
B. RESEARCH CONTRIBUTIONS OF THIS PAPER
Following are the research contributions of this paper:
A detailed taxonomy of blockchain-based Industry 4.0
applications is presented.
A reference architecture having various modules and
components for applicability of blockchain in Industry
4.0 is presented.
The merits and demerits of the current security solutions
which are applicable in Industry 4.0 are discussed.
Finally, the Open issues and challenges in Industry 4.0
based smart applications are presented.
VOLUME 4, 2016 3
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This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI
10.1109/ACCESS.2020.2988579, IEEE Access
Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 1: Comparative analysis of pre-existing surveys on Blockchain with the proposed survey
Au-
thor
Year Objective Pros Cons 1 2 3 4 5 6 7 8
Mettler
et al.
[22]
2016 To explore the
revolution in
healthcare with
blockchain
technology
Database ownership is available with healthcare specialists to coun-
terfeit drugs in the pharmaceutical industry
Not included the latest security
frameworks to be used in Health-
care 4.0.
X3X3X X 3X
Yli-
Huumo
et al.
[25]
2016 To review
the current
research on
blockchain
Uses decentralized environment for transactions; Provides research
gaps
Not mentioned about the future
implementation with blockchain
technology for healthcare etc.
X3XX3X3 3
Ahram
et al.
[26]
2017 To explore the
innovation in
blockchain
Maintains protected health information patients with proper access
rights; Improved robustness, security,privacy, and validity of PHI
Not discussed security and data
access issues
3 3 X3 3 x3X
Weiss
et al.
[28]
2017 To implement
a public
healthcare
system with
blockchain
technology
Eliminates central control and single point of failure; transactions are
time stamped and immutable; improved security and integrity of data
Mobile bandwidth and mobile
data usage are major constraints
3 3 X3 3 X X X
Zhang
et al.
[30]
2017 To evaluate
the metrics of
blockchain
based
healthcare
decentralised
apps
Considers evaluation metrics important for the blockchain technology
with respect to healthcare
Security compliance is missing 3 3 x3 3 X X X
W.
Liu
et al.
[31]
2017 To explore
the advanced
blockchain
architecture
for e-health
system
Distributed databases, peer to peer transmission transparency and
auto tracking, irreversible records computation logic
Public blockchain regulations are
not mentioned; cost of implemen-
tation is high
3 3 X3 3 X3 3
Duan
et al.
[33]
2017 To explore the
applications
of blockchain
technology
in education
domain
Uses automated evaluation software for universities which is imple-
mented through Merkle tree, hash functions, digital signatures and
timestamps
Analysis of different application
domains is not done
3X33X X X X
Radanovic
et al.
[34]
2018 To explore the
opportunities
of blockchain
technology in
the field of
medicine
Cost-effective, optimized, secured and personalized access to stored
health records
Lack of scalability and data ac-
cess control; Not mentioned the
healthcare security standards
X3 3 X3X3X
Kshetri
et al.
[45]
2018 To describe
how
blockchains
are applied
in various
domains in
the developed
countries
Eliminates fraud and corruption in land registry Application-specific solution is
presented; not applicable in other
domains
XXXX3X3X
Fu-
jicic
et al.
[35]
2018 To give an
overview of the
Blockchain,
Bitcoin, and
Etheruem
Provides abstract layering of transactions Mining difficulty after every
2016 blocks in bitcoin; Usecases
except cryptocurrency are not
discussed
3X X 3 3 X X X
Chen
et al.
[36]
2018 To explore the
tokenization of
money using
blockchain and
innovations
Discusses Initial Coin Offering (ICO) mechanism Not discussed the other applica-
tion areas
X X 333X3X
Gat-
teschi
et al.
[37]
2018 To decide
whether to use
blockchain
Highlights blockchain innovations such as transparency, automation,
decentralization and immutability
Does not focus on power con-
sumption, computation and other
hardware requirements
333X3X3X
Nalla-
paneni
et al.
[38]
2018 To assess
the security
aspects of
blockchain;
issues and
challenges in
IoT
Describes important security parameters and issues for IoT domain Does not consider issues related
to large-scale IoT implementa-
tions
3X3X3X X 3
Kon-
stan-
tinidis
et al.
[42]
2018 To discuss
blockchain-
based business
applications
Discusses blockchain applications sector-wise to blockchain No architecture or implementa-
tion is proposed; results of the
survey is not mentioned clearly
X3XX3X X X
Dave
et al.
[46]
2019 To discuss
blockchain-
based business
applications in
Industry 4.0
Exploration on blockchain perspective in IoT applications Scalability and interoperability X3X3 3 X3 3
Mon-
rut
et al.
[47]
2019 Blockchain-
based
applications in
Industry 4.0
Blockchain roles and Issues are explained in detail Tradeoffs and challenges of
blockchain
3X333X3 3
Hathe-
liya
et al.
[48]
2020 security and
Privacy and
security issues
discussed in
healthcare
Privacy and security issues discussed in healthcare Results of the survey is not men-
tioned clearly
X3XX3 3 X X
Pro-
posed
Sur-
vey
2020 Taxonomy of
blockchain
based
Industry 4.0
applications is
presented
The merits and demerits of the current security solutions which are
applicable in Industry 4.0 are discussed
-3 3 3 3 3 3 3 3
1:Architecture, 2: Healthcare, 3: Tabular Comparision, 4: Simulation tool / Framework, 5: Security, 6: Hardware & Physical design, 7: Taxonomy, 8: Open issues and
challenges
4VOLUME 4, 2016
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This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI
10.1109/ACCESS.2020.2988579, IEEE Access
Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 2: Acronyms and their meanings
Acronym Explaination Acronym Explanation Acronym Explanation
ABE Attribute-based encryption EHR Electronic Health Record MOM Manufacturing Operations Management
AI Artificial Intelligence EMR Electronic medical record NIS Network and Information Systems
API Application program interface EOS Enterprise Operating System NIST National Bureau of Standards
ASC Agricultural supply chain ESS Energy storage systems OTC Over-the-counter
BCD Binarycoded decimal EV Electric vehicle P2P Peer to peer
BFT Byzantine fault tolerance EVM Ethereum virtual machine PHI Protected Health Information
BlocHIE BLOCkchain-based model for Health-
care Information Ex- change
HACCP Hazard Analysis and Critical Control
Points
PoA Proof of authority
BPEL Business Process Execution Language HGD Healthcare Data Gateway PoS Proof of stake
BPM Business process management HIPAA Health Insurance Portability and Ac-
countability act
PoW Proof of work
C2C Consumer-to-consumer HITRUST Health Information Trust Alliance PSN Pervasive Social Net- work
COBIT Control Objectives for Information and
Related Technologies
HTTP Hyper Text Transfer protocol R&D Research and development
CSF Common Security Framework ICO Initial coin offering RFID Radio frequency identification
DB Database IDE Integrated development environment RMF Risk Management Framework
DDoS Distributed Denial of Service IEEE Institute of Electrical and Electronics
Engineers
RPC Remote Procedure Call
DER Decentralized energy resources IMR Injection mould redesign RTGS Real-Time Gross Settlement
DES Distibuted energy system IoT Internet of things SCM Supply chain management
DHS Department of Homeland Security ISO International Organization for Standard-
ization
SDK Software development kit
DIACAP Department of Defense Information As-
surance Certification and Accreditation
Process
JS Javascript SDN Software defined networking
DISHA Digital Infor- mation Security in Health-
care,
JSON JavaScript Object Notation SHA256 Secure Hash Algorithm
DLT Distributed Ledger Technology JVM Java virtual machine SPM Supplier performance management
DNX Dot Net eXecution environment kWh Kilowatt hour TUI Text-based user interface
DoD Department Of Defense LC Letter of credit UX User experience
EHD Electronic Healthcare Data LSTM Long Short Term Memory VAT Value Added Tax
FIGURE 3: Organization of the survey
C. ORGANIZATION OF THE PAPER
The structure of the survey is as shown in Fig. 3. Table
2lists all the acronyms used in the paper. Rest of the
paper is organized as follows. The background and history
of the blockchain technology is presented in Section 2. A
reference architecture of blockchain is discussed in Section
3. In Section 4, blockchain deployment for various smart
applications is discussed in detail. Then, Open issues and
research challenges in smart applications are presented in
Section 5. In Section 6, two case studies on smart farming and
tourism and hospitality are presented to give more insights to
the readers. Finally, in Section 7, the paper is concluded with
future research directions.
II. BACKGROUND AND HISTORY OF BLOCKCHAIN
A. TRADITIONAL SECURITY SYSTEM AND
BLOCKCHAIN
In the present era, most of the database systems use a
centralized client-server based architecture. In this systems,
a client (user) has the authority to modify the data stored
in the centralized server. The control of the entire server
database is with the centralized authority who can control and
take decisions with respect to various access control policies
defined on the data stored in the database. They also have
the authority to authenticate users credentials before they
access the database. To resolve the issues in the traditional
centralized systems, blockchain can be an effective solution.
A blockchain is a chain of blocks which can be used to
store and share data in a distributed, transparent and tamper
resistant manner. Each block consists of data and is linked
with other blocks using pointers. Such linkages ensure the
integrity and tamper resistance in the blockchain. When a
new data is added to the blockchain, link to the free end is
created which extends the blockchain by one block or unit.
As more data is added to the blockchain, it gets longer and
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
chain grwos in size. If one of the blocks is modified in the
chain, it breaks cryptographic links which disrupts the whole
blockchain. It also allows the user to verify the integrity of
the stored data.
The risk of the centralized control system can be elim-
inated with an implementation of decentralized systems.
The database authority holds the centralized control on the
security needed for all the users for the required access.
The blockchain stores the data and builds the structural data
storage which makes the network more secure. Due to this,
the blockchain technology makes easy records or transactions
with heterogeneous information in the databases [49].
B. BACKGROUND OF BLOCKCHAIN
The idea of blocks connection by cryptographic chains was
introduced by Stuart Haber and Scott Stornetta in 1991. They
designed a system, in which information or transaction stored
with timestamps can not be modified or tampered. After
that Bayer, Haber, and Stornetta proposed verification and
validation of various transactions using the Merkle tree. In
the Merkle tree, recorded data was gathered into a single
block with an improved quality.
Satoshi Nakamoto created the initial blockchain network
in 2008 [9]. He introduced the hash function method to create
blocks in the chain. The major attempt was to improve the
architecture and development of the blockchain in which
there was no need of sign by the clients or the users. This
implementation build the network for cryptocurrency recog-
nized as bitcoin. The bitcoin network is publicly available
ledger for all the transaction records. In his research work,
blocks and chain were separate words which are combined
together known as blockchain. They got the bitcoin network
file size and the records of its transactions reached up to 20
GB by 2014, which went to 30 GB between the last quarter
of 2014 to 2015. The bitcoin network was pushed from 50GB
to 100 GB in January 2017.
The blockchain is used in the finance or cryptocurrency
applications as it enhances the quality of various applications
with respect to speed, security ease of use, and confiden-
tiality. To explore the possibilities of applying blockchain
technology in various industries, many companies have es-
tablished their research centers for growth of this technology.
For example, IBM has its research center in Singapore
which was inaugurated in July 2016. In November 2016, the
group of world economic forum discussed the development
of the governance models for the blockchain technology.
The global blockchain forum introduced the chamber of
digital commerce in 2016 by Accenture’s trade group. Emma
Macclarkin suggested the use of blockchain to enhance the
trade which was executed by the European parliament’s trade
in 2018.
How blockchain revolutionized: The revolution of
blockchain technology from inception to till today is ex-
plained in detail as shown in Fig 4.
FIGURE 4: Generations of Blockchain
1) Blockchain 1.0
The first generation of the technology was started with the
bitcoin network in 2009, which is known as blockchain 1.0.
In this generation, the creation of the first cryptocurrencies
was introduced. The idea was all about payment and its
functionalities to generate cryptocurrency.
2) Blockchain 2.0
In the second level of the blockchain technology, smart
contract and financial services for various applications were
introduced in 2010. The development of blockchain with
Etheruem and Hyperledger frameworks was proposed in this
generation.
3) Blockchain 3.0
In this generation of blockchains, the convergence towards
the decentralized applications was introduced. Various re-
search areas such as health, governance, IoT, supply-chain,
business, and smart city were considered for building de-
centralized applications [50]. In this level, etheruem, hy-
perledger, and other platforms were used which having the
ability to code smart contracts for a variety of decentralized
applications [51], [52].
4) Blockchain 4.0
This generation mainly focused on services such as public
ledger and distributed databases in real-time. This level has
seamless integration of Industry 4.0-based applications. It
uses the smart contract which eliminates the need for paper-
based contracts and regulates within the network by its con-
sensus [53].
Blockchain Requirements:
Smart Contracts: It is a protocol which allows the per-
formance of transactions in absence of third party that
makes transactions irreversible and traceable.
Tokenization: It is one of the most important things
that must to be included in the blockchain. It facilitates
digital representation of the goods, services, and rights
with the help of tokens. It allows the exchange of values
and trust for different users without involving the central
authority.
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
Data security: Security compliance is a major and es-
sential requirement of blockchain technology with a
legal point of view.
Decentralised data storage: It is a basic requirement of
the distributed system.
Immutability: All the records on the network should
not be modified or tampered in the shared ledger. This
enables the integrity of the stored data.
Consensus: Transactions should only be updated when
all the verified users in the network agree for the same.
Typed Blocks: It is required for the smart contract and for
high speed payment in business transactions. So, data
formatting of the different types of blocks include its
time, consensus algorithm [54], number of transaction
per blocks, and its content data types.
Sharding: It is required for the separation of content over
subsets of nodes in a way, that not all the nodes need to
carry all processing load or any burden.
Access rights management: Encryption based private
and public key cryptography and distributed databases
with user identification is required to assign and manage
access rights.
Standards used to manage permissioned blockchains:
Immutability of the blockchain network makes the data
access in a specific order. The public certificates are
available in public blockchain, but without having the
private key, authorization cannot be provided to the
users. So, all the data should be managed in order of
data elements like user’s internet protocol (IP) address,
name, its code, and extensible markup language. These
all are published to the consortium with the communi-
cation process.
Standard data formatting: In the blockchain system,
it is also needed to standardize the data formats with
respect to Application Programming Interfaces (API).
Each organization in the blockchain network needs to
use the same data format or APIs to communicate in the
same network.
Updatability: The need for data updation in the dis-
tributed ledger is most important for records. In a peer-
to-peer network, data needs to be structured and system-
atically updated for each node that transacts within the
network.
P2P encryption between blockchain nodes: Encryption
is needed to secure the transactions between the end
nodes that may link together in the blockchain protocol.
UX: One of the major factors in a system is the user in-
terface design that provides an easy and convenient ap-
plication environment to the users. The main difference
between the blockchain-based and non-blockchain-
based systems is the manner in which the user perceives
it.
Development operation: The main step in the production
of the system is the selection of platforms that requires
less time and the setup complexity.
FIGURE 5: The basic blockchain-based architecture
III. BLOCKCHAIN ARCHITECTURE AND ITS
COMPONENTS
A. BASIC BLOCKCHAIN BASED ARCHITECTURE
In the basic architecture of the blockchain, each transaction
needs to be verified which can not be altered as shown in Fig.
5.
Addition of transactions in the block structure: A blockchain
transaction has various steps. First, a network node or user
requests for a new transaction. After that, the transaction is
recorded in the block format or structure. The block structure
consists of the index, time-stamp, data, previous hash, and
current block hash.
Transmission to peer nodes: A block of transactions is
broadcasted to the peer nodes available in the network.
Validation of transactions: The blockchain network uses
SHA-256 algorithm for creating a unique hash. Each block
in the blockchain is linked with the hash of the previous
block which makes an unbreakable network of transactions.
If someone tries to append a transaction, then it must be
validated by the network nodes or by smart contracts, and
consensus. This immutable ledger cannot be modified, it
can only be appended to the transaction of blocks, which
results in a secured and reliable decentralized system. Various
algorithms are used to validate transactions and user status.
Block added to ledger: The new transactions are first
verified by the other nodes and then they are added in a
new block for the ledger or chain. The existing blockchain
is extended by addition of a new block that is unalterable and
undeletable for any other users.
B. REFERENCE ARCHITECTURE
The blockchain reference architecture consists of three dif-
ferent networks which combine together and run the whole
blockchain application for the users. The three different net-
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works are the public network, cloud network, and enterprise
network as shown in Fig 6. Each has its own capabilities and
functionalities for the smooth working of the decentralized
applications.
1) Public network: In this network, the users, edge
services, and peer cloud providers are connected or linked
together.
Users: In the public network, the users manage the dis-
tribution and creation of the blockchain decentralized ap-
plication and execute the operations with the help of the
blockchain network. Users have different roles as follows:
Developer: Developers make various types of applica-
tions for the client or users with different functionalities.
They develop the smart contract for the interaction with
the users which helps to add transactions or records within
the blockchain network. The developers can also build the
inheritance applications for facilitating communication in the
blockchain.
Administrator: The functionality of the administrator is to
produce, maintain, and configure decentralized applications
for the blockchain network.
Operator: Operators have the control to monitor and man-
age the blockchain network and its applications.
Auditor: The blockchain auditors maintain or review the
history of the transactions over the blockchain network for
business and legal compliance point of view.
Edge Services: These services authorize the information
that gets transferred via the internet to the cloud, enterprise
applications, and client applications. They maintain systems
such as domain name systems, content delivery networks,
firewalls, and load balancers. Domain name systems are used
to correct the Uniform Resource Locator (URL) of the web
sites that are linked to the Transmission Control Protocol-
Internet Protocol (TCP-IP) address for the system which is
to be used for the resources. The content delivery network
carries user applications, which gives the geolocation for
the distributed systems which are installed to minimize the
response time for the distributed users in the network. The
firewall is responsible to maintain and give access control to
the incoming and outgoing traffic in the network allowing
or blocking the access. The load balancers are used for
the distribution of the network traffic to maintain minimum
response time, latency, and maximize throughput across the
resources such as computers, processors, and storage sys-
tems. They are needed to balance the load in local and global
systems.
2) Interaction option: In the blockchain, there are various
ways through which users can interact with the blockchain
network, they are shown below as:
Software development kit: The SDK is useful for facili-
tating interaction between applications and their platforms.
Blockchain application development lifecycle has a number
of phases such as developing phase, debugging phase, testing
phase, and production phase. The blockchain applications
need to interact and communicate with the network when the
software development cycle executes.
Client software development kit: It is a client-side pro-
gramming library, which provides API methods to be used
by the end user program to give access functionality within
the blockchain network. The programs are written in Java,
Python, and other languages and the kit also supports devel-
opment tools.
Command line interface: Developers and administrator
usually need activities such as monitoring, managing ac-
counts of users, and importing & exporting some text com-
mands formats. All these activities can be executed through
the command line interface.
3) Cloud network: The cloud network consists of a va-
riety of running nodes, each with its own capability and
functionality. The cloud network includes the blockchain
applications, application programming interface, blockchain
services, security services, and system integration.
Blockchain applications: There are various types of appli-
cations such as web application, end-user applications and
server-based applications. Users play different roles such
as business users, administrators, auditors, and operators.
The blockchain applications use the APIs for the post and
get services of the resources like databases. A variety of
applications such as healthcare, financial sector, insurance,
energy domain, supply-chain, and IoT can be enabled with
the blockchain to minimize the cost and time [55]–[60].
Application programming interface: An API is useful for
the developers and users to reuse the data or information
and its analytics with their services. It can be called by dif-
ferent cross-platform technologies. Blockchain technology
provides various APIs for the application interfaces to use the
components that can be handled in the business transactions.
Blockchain services: For the performance and functional
environment of the blockchain systems, there is a range of
services such as:
Members: This service manages the user ids, credentials,
and the history of users transactions in a confidential manner
over the blockchain network. The permissioned network
needs to validate the users of ongoing transactions and the
users identification for the record of transaction and verifi-
cation, so it requires membership in the network. In such
networks, users have the access control to allow or block
the transaction. In a non-permissioned network, it does not
require the authorization by the user while submitting the
transaction details.
Consensus: Consensus is a protocol in the blockchain net-
work, which must be followed by each node in the network.
This protocol specifies time validity and rules that need to be
followed by all the nodes or users in the network to perform
various tasks or append transactions in the blockchain net-
work. It also maintains a copy of the ledger in the network.
Ledger: All the transactions are linked together with a
cryptographic hash in the blocks to form a ledger.
Smart contract: In general, a smart contract is a chain
of the codes, which executes in the blockchain network
environment. This code chain communicates the conditions
or rules for different parties to follow the terms between
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FIGURE 6: A blockchain-based reference architecture
the nodes or users in the network. Smart contract can be
developed in the blockchain platform with the help of the
supported programming languages.
Secure runtime: In the secure runtime environment,
blockchain transactions are added in the ledger with the
secured container such as secure OS, and library of the
programming language runtime used.
Event distribution: In the blockchain network, the pub-
lisher notifies the subscribers for a specific event. The no-
tification is sent in a broadcast manner within the network.
Subscribers who subscribe to a specific publisher or events
receive the notification.
System integration: The blockchain services and the en-
terprise network are combined or integrated together via
the application programming interface and enterprise service
bus.
Connectivity: The connectivity between the cloud network
and the enterprise network is established by the Virtual
Private Network (VPN) or the gateway tunnel. It enables
the secure connectivity and standard data format and filters
within the blockchain network.
4) Enterprise network: The enterprise network consists of
the enterprise directory, its applications, and the database.
Enterprise user directory: In the enterprise applications,
data or information regarding user authentication, authoriza-
tion, and personal data of users are recorded. The gateway
and virtual private network (VPN) maintain secured services
for the access control of the users.
Enterprise applications: These applications are used for
the enterprise that communicates with the blockchain net-
work. They also communicate with smart contracts in the
network. Hence, smart contract collect and store the enter-
prise data in the network and share that information over
the applications. They also make requests for availing the
services in the blockchain network.
Enterprise data: The enterprise application in the
blockchain records and maintains the metadata of the system.
It also maintains the feedback of the system that contains
the entire history of the blockchain network. Transactional
data contains all the records of the network which includes
master repository, financial information, and business com-
munication. All the data is available via data repository
and distributed data storage. The second type of blockchain
enterprise data is application data in which, data is collected
and produced by enterprise applications and its operations.
All the values are added for a better understanding of the
application performance. The log data is recorded in log
files for future inspection for the security, governance, or
compliance.
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 3: State-of-the-art proposals/Tools used for Blockchain-based Security system
Author
/ Devel-
oper
Name
of tool
/frame-
work
Year Objective Techniques Used SetupDescription Coding / Simula-
tor
Open-
source
Pros Cons
Samir
Damani Minthealth
2013 Toimplement a global and decentralized health plat-
form to provide patient empowerment and improve
clinical outcomes with low cost.
Decentralized health
information
Service-based framework
which provides features to the
end users.
Not available No Efficientstorage of health records, advanced security
framework
Expensive to access
Casey
Kuhlman
et al.
Monax 2014 To assist developersto build, ship, and run processes
for blockchain and smart contract-based applications
for business systems
Database centric Permissioned blockchain net-
work
Solidity Contract-
Oriented
Programming
Language
Yes Used data centric approach rather than cryptocur-
rency centric approach
Issue of trust not exploited to its full
potential
Coin
science
ltd.
Multi-
chain
2014 Tocreate and deploy private blockchains and provide
a direct interface to facilitate the permissioned net-
works
Multiple keys for se-
curity
Connection of two server nodes
in a round-robin manner to cre-
ate blockchain
C++, JSON RPC
interface
Yes Scalability, High performance (can process 1000
transactions per second), easy API, and adjustable
permissions for every type of action
No smart contracts, Low interoper-
ability, and not fully decentralized
Digital
Treasury
Corpo-
ration
PhrOS 2014 To create a healthy and civilized new society with
improved data security and interoperability; to in-
crease healthcare Industry collaboration
Hybrid blockchain
and smart contract
Requires smart devices at In-
dustry level
Not available No Identity authentication, distribute data lake, smart
contract, and standard API development standard
Expensive to access.
Chain Chain
Core
2014 To maintain a cryptographically-secured multi-
assisted shared ledger.
Permissioned
blockchain networks
Installation of chain from git
clone and
Java, ruby, nodejs Yes Runs locally in machines like mac, windows, linux
to create blockhain networks and modifies existing
network
Limited support
Stellar
Devel-
opment
Founda-
tion
Stellar 2014 Todevelop a distributed payment system, and REST-
ful APIs servers using its database.
Decentralized
network
Http client based api and in-
stalled on OS x, Windows, and
Linux
Not available Yes Connects banks, payment systems, and customers;
integration for transferring currency fast; minimized
cost
Limited to cryptocurrency
Brainbot
tech-
nologies
and
Ethereum
project
Hy-
drachain
2015 To extend the Ethereum platform to create permis-
sioned distributed ledgers for private chain or con-
sortium chain setups
Permissioned
distributed ledger
Used cloning command setup
to execute.
Python Yes Compatibile to the Ethereum Protocol, accountable
validators, and nativecontracts
Partial trusted mechanism for a third
party.
Vitalik
Buterin
et al.
Ethereum
2015 To develop a public blockchain-based distributed
computing platform
Decentralized com-
puting
Virtual machines installed via
commands to generate the au-
thority and transaction account
Go, C++, Rust Yes Decentralized, immutable, safe, and secure. Prone to more technical errors
The
Linux
Founda-
tion
Hyper-
ledger
fabric
2015 To build a modular architecture to host any main-
stream language for smart contracts development
P2P transactions,
chaincode
SDK like go, java node Node JS, Java, Go Yes Scalable, rich querying capability, hardware-based
protection of digital keys, and rich community sup-
port
Lack of proven use cases and inad-
equate number of skilled program-
mers.
Coin-
prism,
Inc.
Open-
Blockchain
2015 To manage and generate digital assets in automated,
secured and scalable ways.
Distributed ledger
technology
Used DNX application, docker,
openchain server; configuration
of admin key to control server
C#, javascript Yes Consensus mechanism to verify digitally signatured
transactions
Does not use the concept of blocks
David E
Rutter
R3
Corda
2016 To build interoperable network with regulated pri-
vacy
smart contract tech-
nology
Used JavaSDK, Git, Intelji IDE
to setup Corda environment;
configured with Kaitlin plugins.
Javaand JVM lan-
guages
Yes JAVAand other JVM languages for smart contracts;
distributed network; notary based system to verify
transactions; eliminates global broadcast
Transaction level; specific under-
standing of notary nodes
JP mor-
gan
Quorum 2016 To enhance financial services and privacy; permis-
sioned authentication for transactions
Distributed
ledger protocol,
permisionned based
network using
etheruem
Installation of virtual box and
vagrant with gaoling and github
clones in different environment
The go Ethereum
library
Yes Transaction and contract privacy; Multiple voting-
based consensus mechanisms; Network/Peer permis-
sions management
Transaction level; public access to
ledger
Bruce
Pon BigchainDB
2016 To implement scalable, decentralized immutable
ledger and its own assets for exchange services
Decentralization,
immutability, built-
in assets & tokens
From git clone the bigchaindb
and set up commands for mak-
ing transactions.
Python, node js Yes Decentralized, immutable, Native Support of Multi-
assets, Byzantine Fault Tolerant, Requires low la-
tency,customizable, Can be public or private
The lower layer directly uses Mon-
goDB’s consensus to decide whether
to store a transaction; The higher
level has federation-style voting on
whether a transaction is valid or not
The
Linux
Founda-
tion
Hyper-
ledger
saw
tooth
2016 To support multi organization transactions and ex-
change values over different entities throughout the
network
Umbrella strategy Installation of docker and saw-
tooth; environment setup with
terminal open sawtooth.
Go, javascript,
python
Yes Onchain governance, advanced transaction execution
engine, support for Ethereum, upgrades consensus
mechanism, incorporation of scalable algorithm.
The
Linux
Founda-
tion
Hyper-
ledger
iroha
2016 To giveinfrastructure for handheld devices and web
supports; new consensus mechanisms for fabric net-
work; environment for C++ developersto contribute
to open source library
Permissioned
blockchain system
Creation and installation of
docker network, initialization
of posterSQL container, cre-
ation of blockstore, configura-
tion of iroha network, Launch-
ing of iroha daemon
Python, Java,
Javascript,
C++ with BFT
ordering service,
android and iOS
mobile platform
Yes Simple deployment and maintenance, variety of li-
braries for developers, role-based access control,
modular design, command-driven, query separation
principle, assets and identity management
Performance issues
The
Linux
Founda-
tion
Hyper-
ledger
burrow
2016 To leverage Hyperledger Burrow’s permissioned
EVM runtime to complement a variety of other com-
plex networksfrom both the public blockchain sector
as well as the enterprise blockchain world
Permissioned
Ethereum; smart-
contract blockchain
node
Install Go, Clone-configure-run
burrow,logging
Solodity Yes Transaction finality; high transaction throughput;
Tendermint consensus engine, Application
Blockchain Interface, API Gateways
Integration of Ethereum Virtual Ma-
chine by Burrow
sovrin Hyper-
ledger
indy
2017 To operate tools, libraries and reusable components
for providing identity with distributed ledger; inter-
operability of administrative domains
Distributed identity
ledger
Installation of docker and Indy
SDK with GitHub clone
Node JS Yes Distributed ledger; decentralized identity,
correlation-resistant design, decentralized identifiers,
pairwise identifiers
Not active, under incubation
testnet3
Blockchain
Testnet
2015 Toprovide replacement to bitcoin isolated private net-
work
Execution with docker, deploy-
ment of blocks, docker con-
tainer
Not available Yes Providesinfrastructure for testing purpose only with
the help of bitcoin functionalities without modifying
chain in the bitcoin network
Only limited to cryptocurrency
Mi-
crosoft
BaaS:
blockchain
as a
service
by Mi-
crosoft
2016 Toprovide Blockchain technology as a service Cloud-based
services and Agile
infrastructure
BaaS to maintain and setup
blockchain connected nodes
Cloud-based sim-
ulation
No Initiative for cryptocurrency and smart contract Expensive
IBM IBM
Bluemix
Blockchain
2016 Touse Blockchain software as a service Distributed, permis-
sioned, immutable
Cloud-based software as ser-
vice
Not open source
and hence not dis-
closed
No Used in food safety network, private equity network,
trusted identity network; secure, scalable, and robust
Costly for services
Lisk
founda-
tion
Lisk 2016 To give access for next generation cryptocurrency
and its decentralized systems
Consensus
algorithm,
security, blocks,
transactions and P2P
communications
Install node JS, Postresql,
Swagger, Redis, Install lisk
core
Javascript Yes Decentralization of the Lisk network, Post transac-
tions to the Lisk blockchain
Youngnetwork, Javascript-only, gen-
eralized risk
Alexan-
der
Ivanov
Waves 2016 To launch customized cryptocurrency tokens Proof-of-stake, Peer-
to-peer network
Waves client, API, Mobile
SDK,
Javascript, C, C#,
Java, Typescript,
Shell
Yes Financialoperations, issue tokens and trade Only for cryptocurrency
GmbH Embark 2017 To allow easy development and deployment of de-
centralized applications
Decentralized and
server-less HTML5,
Swarm support for
deployment
Needs node.js and embark Javascript, node
js, HTML5
Yes Automation of smart contract using Javascriptcodes,
automatic redeployment of contracts over the net-
work
Not available for all platforms
sym-
biont.io
Sym-
biont
Assem-
bly
2017 Todevelop smart contract for providing the standard
security,reliability and performance
Distributed ledger Calling API Go Yes Powerful, secure, robust, smart contract No network, no BFT and no persis-
tent storage
IV. BLOCKCHAIN DEPLOYMENT IN SMART
APPLICATIONS
The detailed taxonomy of blockchain deployment in real-
time applications such as energy, healthcare, manufacturing,
agriculture, business, digital content distribution, smart city,
IoT [61], supply-chain & logistics, and tourism & hospitality
[62] is shown in Fig. 7. Table 3provides the detailed rela-
tive comparison of the State-of-the-art proposals/Tools used
for blockchain-based security system. Parameters used for
this comparison are objectives, techniques used, setup type,
programming languages or simulators, pros, and cons of the
existing tools/frameworks.
A. SUPPLYCHAIN AND LOGISTICS
Agricultural applications need critical management inputs,
such as supply-chain management (SCM) which plays a
prominent role in human lives. Traditional logistic systems
used in food-supply and agriculture simply store the orders
and delivered them to the destination. These conventional
systems have a lacuna with respect to various features such
as auditability, traceability, and transparency [63]. However,
in the modern digital era, these features can improve safety
10 VOLUME 4, 2016
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
FIGURE 7: Taxonomy of Blockchain for Industry 4.0
and food quality, and hence, there is a huge demand of
good quality of food by consumers [64]. Hence, most of the
research & development(R&D) organizations adopt IoT tech-
nologies such as wireless sensor networks (WSN), and radio
frequency identifications (RFIDs), which remotely observe
the food supply-chain.
According to Caro et al. [65], most of the centralized
cloud infrastructures are being used as current IoT solutions
in SCM. These infrastructures usually have open issues like
data integrity, lack of transparency, tampering and single
point of failure. These issues can be handled in an efficient
way by using blockchains. Decentralized trustful systems
can be designed for the same by using the blockchain. A
decentralized, blockchain-based solution named AgriBlock-
IoT, was proposed in [65] for Agri-Food SPM. It integrated
various IoT sensor devices which produced and consumed
data along the chain. The stored data can be accessed, and au-
tonomous executable smart-contracts could be implemented
through AgriblockIoT, with the objective of achieving trans-
parency, and inflexibility of the records in an environment,
that uses modern devices such as mini-PC and gateways. The
performance and efficiency of AgriblockIoT are quantified
in terms of CPU load, network traffic, and latency. The
performance can be improved by working on the constrained
hardware architectures.
Perboli et al. [66] suggested that the blockchain improves
the reliability, efficiency, and transparency of supply-chain,
and speedup inbound processes. Though many IoT technolo-
gies are used for food safety and SCM, there are some issues
which are not properly addressed. The major issue is to de-
cide whether the information or data shared among the mem-
bers of other supply-chain is trustworthy or not. To overcome
this issue, authors of [64] proposed a system called Hazard
Analysis and Critical Control Points (HACCP), which pro-
vided real-time food tracing information to all SCM members
and has features like reliability, openness, neutrality, security,
and transparency.
Weber et al. [75] proposed a blockchain based decen-
tralized solution to solve the problem of determining if the
information or data shared among the members of the supply-
chain is trustworthy in collaborative processes. They also
discussed various notations and process models for business.
The prototype model was implemented using blockchain and
validated through business processes [76]. To execute busi-
ness transactions securely, a model called business process
management(BPM) was proposed by Guerreiro et al. [77].
This model used the blockchain technology and an Enterprise
Operating System (EOS). The risk involved in the secured
execution of business transactions was eliminated in the
proposed model by increasing trust, authenticity, robustness,
and traceability against fraud.
An Agricultural Supply Chain (ASC) system was pre-
sented in [72] by Leng et al. This system was completely
dependent on the double chain architecture which accelerated
the efficiency of the blockchain in the ASC. The authors
suggested solutions to provide adaptive rent-seeking and
matching mechanisms for public service platform. These
solutions ensured transparency, security and privacy of the
enterprise information. Moreover, the use of public service
platform and the efficiency of the system were also improved.
The proposed system had drawbacks mainly in terms of
performance and increased size of the blockchain.
Mao et al. [78] proposed a credit evaluation system which
was based on public blockchains. This system helped in
the management and supervision especially for the food-
supply chain to improve the effectiveness. In particular, the
authors gathered the credit evaluation text from the traders
by smart contracts on the blockchain, and then analyzed
VOLUME 4, 2016 11
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 4: Supply chain management with blockchain technology
;
Author Year Objective 1 2 3 4 5 6 7 8 9 Pros Cons
Tian et
al. [67]
2016 To adopt unique codes or tags for
agri foods supply chain systems
3 3 3 3 3 3 3 X3Tracking of products, eliminates frauds High implementa-
tion cost; immatu-
rity of blockchain
technology.
Tian et
al. [64]
2017 To adopt blockchain network in
food supply chain tracking systems
3 3 3 3 3 3 3 X3All processes of supply chain are enabled with produc-
tion link, processing link, warehouse management link,
distribution, and retailers link
Highlighted only
conceptual model;
no practical
implementation
Tse et
al. [68]
2017 To explore blockchain usage using
information security in food supply
3 3 X333X X 3Promotes government tracking and monitoring; audits on
chain, records immutable ledger
Highlighted
comparison
of traditional
food supply and
blockchain based
supply chain, not
implemented
Kshetri
et al.
[69]
2017 To explore the blockchain roles in
supply chain management
3 3 X3X3X X 3Increases transparency and accountability Needs high degree
of computerization
and compliance
with regulations,
law etc.
Per-
boli
et al.
[66]
2018 To create a network using
blockchain technology with
producers, distributors, certifiers,
retailers and customers for supply
chain.
3 3 x3 3 3 3 3 3 Enhanced efficiency,reliability, trust and optimization of
processes
Validation,
Scalability and
cost.
Kuhi
et al.
[70]
2018 To implement the performance
measurement system for supply
chain with blockchain technology
3 3 X333X3 3 Improved validation and verification, efficiency, trans-
parency
High transaction
cost with etheruem
Caro et
al. [65]
2018 Toimplement tracking of agri foods
in supply chain management
3 3 3 3 3 3 3 3 3 Reduced cost and improved performance and traceability
with etheruem and sawtooth implementation
No implementation
of hardware com-
patibility
Min et
al. [71]
2018 To explore blockchain technology
for enhancing supply chain re-
silience
3 3 3 3 3 3 X X 3More transparent and faster communication of the supply
chain
Not implemented
Kaijun
et al.
[72]
2018 To explore agriculture supply chain
system with double chain design
3 3 X3 3 3 3 3 3 Overall efficiency, transparency, security, openness in
transactions
Larger amount of
resources needs
to be optimized
for speed and
efficiency; Platform
credibility.
Azzi et
al. [73]
2019 The power of a blockchain-based
supply chain
3 3 X X 3X3 3 3 Security, openness in transactions Scalabilty
Christoph
et al.
[74]
2019 A blockchain-based transaction
cost theory perspective in
supplychain industry
3 3 X X 3X X 3 3 Better performance measurement No implementation
Litke
et al.
[74]
2019 Blockchain perspective in supply-
chain
3 3 X X 3XXX3Scalability, consensus mechanism, and privacyconsider-
ations
Lack of
performance
monitoring
1: Transparency,2: Reliability, 3 : IOT, 4: Security,5: Architecture, 6: Consensus transaction mechanism, 7 : Traceability system, 8: Framework, and 9: Immaturity of blockchain
the text using a deep learning method named Long Short
Term Memory (LSTM). Though the authors claimed the
effectiveness of their method, but they did not consider the
overall system costs and benefits. Due to these issues, they
can not provide a standard methodology to design, develop,
and validate the overall blockchain solution. Later on, the
authors in [66] concentrated on one of the most critical issues,
i.e, the implementation of the blockchain in the supply-chain
with the need of including all the different actors. Moreover,
the sharing of information along the entire blockchain could
lead to inertia in adopting the solution. For this reason,
a correct implementation of the blockchain technology in
the supply-chain must starts from an analysis of the needs
and the objectives of the different actors involved. Keeping
this objective in mind, the authors created a business model
capable of highlighting the returns in terms of both economic
and customer satisfaction.
Kshetri et al. [69] presented an early evidence of linking
the use of the blockchain in supply-chain activities to in-
crease transparency and accountability. They also examined
how the blockchain is likely to affect the key SPM objectives
such as cost, quality, speed, dependability, risk reduction,
sustainability, and flexibility.
A public blockchain of the agricultural supply-chain sys-
tem based on the double chain architecture was proposed
by Kaijun et al. [72]. In this system, the authors mainly
focused on the dual chain structure and its storage mode,
resource rent-seeking and matching mechanism, and consen-
sus algorithm. The results exhibited that the double chain
structure based agricultural supply-chain could take care of
the openness and security of transaction information and
the privacy of the enterprise information. It also had the
ability to complete rent-seeking and matching of resources
self-adaptively. Therefore, the proposed architecture greatly
enhanced the credibility of the public service platform and
the overall efficiency of the system.
Table IV provides the detailed relative comparison of the
existing blockchain based approaches for supply-chain &
logistics systems using the parameters such as the trans-
parency, reliability, security, architecture, consensus mech-
anism, traceability system, framework, pros, and cons of the
existing approaches.
B. ENERGY DOMAIN
Energy is the actual base of our existence. It is essential
to the lives of humans and all other living organisms on
earth. Humans and all the living creatures on the earth cannot
survive in the absence of energy. We use energy for a va-
riety of purposes like food, Communication, transportation,
heating/cooling, and lighting. All conventional transportation
means such as trains, buses, automobiles, and airplanes work
on energy, which is derived from electricity, and fossil fuels.
12 VOLUME 4, 2016
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 5: Energy applications with blockchain technology
Author Year Objective 1 2 3 4 5 6 7 Pros Cons
Kos et
al. [79]
2016 To create autonomous selection of
electric vehicle charging station with
blockchain
3333333Transparency, efficiency, machine-to-
machine transactions
Scalability
Swiatek
et al.
[80]
2017 To explore decentralised energy
production and consumption using
green energy blockchain
3 3 3 3 X33Tracking of records, easy maintenance, op-
timization
Lack of interoperability, stability
Noor et
al. [81]
2018 To manage energy requirement with
micro grid network
3333333Organised, trustable operations; eliminates
middlemen
Privacy, social cohesion, inclusiveness,
solidarity
Truly et
al. [82]
2018 To select regulatory compliance for
decreasing the energy consumption
X X X X X 33Enhanced trust, security, legal and policy
tools
Mining, climate change mitigation
Nallapa-
neni et
al. [83]
2018 To maintain vast range of services in
distributed energy system
3333333Monitoring, sharing and trading financial
flows; emission of records
Lack of reliability, stability and effi-
ciency; old grid infrastructure and design;
loss of energy
De-
Cusatis
et al.
[84]
2018 To secure decentralised energy re-
source management using etheruem
blockchain
3333333Easy identification and authenticition using
smart contract
Spoofing attacks, port scans and DDoS
Kang et
al. [85]
2018 To develop energy trading platform
for homes in micro grid infrastruc-
ture
3333333Automation of renewable micro grid en-
ergy and its trading
Lack of interoperability, stability
Hinter-
stocker
et al.
[86]
2018 To discuss potential impact of
blockchain solution on energy
markets
3X X X 333Reduced costs and efforts; efficient pro-
cessing
implementation
Ashley
et al.
[87]
2018 To establish trust for renewable en-
ergy credits over the system
3X3X333Secure and transparent distributed ledger,
smart contracts
Immaturity of technology; lack of inter-
operability, scalability
Plaza et
al. [88]
2018 To implement distributed solar self
consumption and blockchain
3333333Smart meters; reduced cost; distributed
consumption
Lack of scalability and interoperability
Wang et
al. [89]
2018 To explore contract based energy
blockchain for securing electric vehi-
cles charging with smart community
3333333Improved energy efficiency and sustain-
ability, energy generation
Not full proof trust mechanism
Andoni
et al.
[90]
2019 In-depth survey on energy sector:
Blockchain perspective
3 3 X X 333P2P energy trading Market barriers
Zhu et
al. [91]
2019 Application of Blockchain Technol-
ogy in Energy
3X3X3X3Distributed trading rules for grid Consensus algorithms is not discussed in
detail
1: Distributed energy system 2 : IOT 3 : Micro grid network 4 : Architecture5 : Smart meter 6 : Peer to Peer trading 7 : Renewable energy source
Our food is grown with considerable energy expenditure,
and its storage and transportation also consume energy. Our
modes of communication, such as internet and telephones run
on electricity. Sun is the major source of all energies available
on the earth. It is very important to select the type of energy
resources carefully, because it can lead to adverse effects on
the environment such as global warming, and pollution.
Energy resources are classified into two categories: non-
renewable resources and renewable resources. The exponen-
tial use of non-renewable resources may lead to rare existence
of these resources. So, it is very important to manage them
with intense care and proper management. Proper usage of
non-renewable resources has become mandatory due to their
scarcity. The use of renewable energy sources such as solar
power or wind can leverage energy efficiency to maintain
the ecosystem [92]. Hence nowadays, most of the countries
encourage their people to use renewable energy resources for
the growth of their industries, agriculture, and transportation.
1) Distributed Energy system
Distributed Energy System (DES) is one of the important
concepts in the energy domain. DES generates power on
decentralized levels. It also enhances the overall throughput
quality of the energy system by considering the parameters
like energy production, economics, and environment. DES
overcomes the many challenges of the centralized energy
network systems and maximizes the use of renewable sources
for a distributed generation of energy [93]. With the use of
IoT, Artificial Intelligence (AI) and Machine Learning (ML),
DES has made it quite simple to monitor and maintain data
and records. With its due popularity, DES has brought a
significant improvement in the sector of electric utility which
gives the ambit for the expansion of renewables empowered
digital services.
Nowadays, there are many evolving technologies are avail-
able which can simply convert energy into a digital. Using
such technologies, we can keep a closer watch on a DES
which is placed at a remote location. Moreover, the IoT plays
a vital role in energy transitions and hence is adopted by DES.
The presence of the blockchain and IoT facilitates a wide
range of services enabled by the DES. In fact, the blockchain
technology and IoT get the credit of giving a digital look to
DES for energy transitions. The application of the blockchain
in DES helps it to have a trustworthy data flow among emis-
sion traders, energy traders, energy producers, and operating
staff. Digital DES offers a high level of security, and scope for
decision making and processing based on the real conditions.
The blockchain also helps to generate energy efficiently.
There are numerous scenarios where energy sharing DES
is more appropriate and better than the conventional DES.
The Blockchain technology provides a decentralized energy
trading platform for the imports and exports of energy, which
can monitor electricity flows and aid to maintain them by
time stamping [83].
DES is a truly intelligent system that provides a broad
range of services in various stages such as the operating
stage, development phase, energy trading stage, and energy
metering phase. Authors of [83] did not highlight the issues
like old grid infrastructure, reliability, energy loss, stability,
environmental concerns, obsolete design, less efficiency in
transmission, generation and distribution.
Truby et al. [82] described how to improve environmen-
tally sustainable development of the blockchain applications.
Their study was based on the fiscal policy and regulatory
VOLUME 4, 2016 13
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
approaches for the digital currencies [58]. This research
led them towards the proposal and establishment of some
new policy tools and legal tools which are required for
the consumption of energy with the usage of blockchain
technologies. Authors [82] also came up with the fiscal policy
for the same purpose and suggested the use of the blockchain
technology.
2) Microgrid
Small-scale power stations which have their own production
as well as storage resources are known as microgrids. A
microgrid always has definite boundaries. It can be perceived
as a tiny cluster of electricity users who have a local source
of electricity supply. The clusters are connected to a national
grid which operates independently. If a microgrid is con-
nected to the main grid, it is known as a hybrid microgrid.
Decentralized Energy Resources (DER) such as diesel gen-
erators, PV Panels and a group of loads are integrated with
Energy Storage Systems (ESS) like flywheels and batteries
to form a microgrid and provide electricity [79].
Decentralized flexibility created by renewable energy
sources can be easily reduced by approach, i.e, microgrids.
Goranovic et al. [94] suggested the two approaches for
controlling electric grids, i.e, decentralized and centralized
monitoring systems. In the centralized monitoring systems,
an operator is accountable to execute the whole system.
The use of centralized control devices needs expensive in-
frastructure. Centralized systems measure and process the
data and then set proper proceeding in the circumstances.
Multiple points can be made available in the system through
which information is sent and received by the communication
channels and centralized control devices. The major draw-
back in this mechanism is that the use of multiple points in
the centralized system increases the probability of system
failure. This limitation of the centralized system can be
conquered by the decentralized system where each device
independently controls itself. The decentralized system also
improves the fault tolerance and communication speed of the
system. The decentralized blockchain is precisely suitable
to implement business processes in microgrids using smart
contracts [95]. Authors of this paper also provided a few
examples of the blockchain projects for microgrids with
certain technical parameters. The type of the blockchain,
consensus mechanism and availability of parts required in
the hardware development or open source were the techni-
cal parameters considered by the authors for describing the
example microgrid projects [94]. A brief summary of these
projects is given below.
I) PowerLedger: It was a blockchain based market clearing
& trading mechanism [96]. It included the use of private
Ethereum with Proof-of-Work (PoW) and public eco-chain
that employed proof-of-Stack (PoS). This was an open source
project.
II) Share&Charge: It was a group of Electric Based Vehicle
(EBV) charging stations [97] which used public Ethereum
and consensus algorithm as a PoW. Owners can register his or
her station to fix charging tariffs. Any charging station could
be integrated and combined to Share&Charge network [79]
through Share&Charge module.
III) NRGcoin: This framework was based on energy cryp-
tocurrency developed through a smart contract. It operated
through gateways which simply calculated the flow of elec-
tricity and communicated through a smart contract.
IV) GrunStromJeton: It was an Ethereum based conceptual
framework developed to verify the actual use of electricity. It
used PoA as a consensus mechanism.
V) SolarCoin: It was developed to enhance the mass pro-
duction of solar energy. Due to the lengthy setup process,
customers usually do not go for solar installations. This
project aimed at eliminating this problem by giving rewards
to buyers. One solarCoin was given as a reward per produced
MWh. It used PoW as a consensus mechanism and bitcoin as
cryptocurrency.
VI) GridSingulartiy: It was a decentralized data exchange
framework specially designed for energy sector emphasizing
on electricity, water, gas, and heat. In this platform, PoA
and PoW were the consensus algorithms which used public
Ethereum.
VII) Electron: It is a Company which works in the energy
sector and provides Ethereum based better solutions.
Apart from the above projects, people are currently work-
ing on numerous projects in the same domain. Table V
provides the detailed relative comparison of the existing
blockchain-based approaches in the energy domain using
parameters such as the objective, transparency, reliability,
security, architecture, consensus mechanism, traceability sys-
tem, framework, pros, and cons of the existing approaches.
C. DIGITAL CONTENT DISTRIBUTION
Since the commercialization of the internet in 1994, deliv-
ery services of digital content has been increased exponen-
tially. [98]. Delivery systems are mainly of two types: non-
protected and protected delivery systems. Generally, digital
content is protected using the conventional encryption mech-
anism. Different encryption mechanisms use different ways
to generate, propagate, and maintain the keys and decrypt
the encrypted content with keys. Traditional systems such as
Conditional Access System and Digital Rights Management
(DRM) are popular for protecting digital content, but face
some major issues like network attacks, stealing of keys, and
pirate attacking.
To overcome the drawbacks of the conventional central-
ized system, the authors of [98] proposed a decentralized
digital content distribution system based on the blockchain.
In this digital content system, the owner of the actual content
could supervise and control the security as well as simplicity.
The use of the mining techniques ensured that the addition
of each type of transaction to the blockchain. PoW was used
as the consensus mechanism to guarantee the security and
privacy of the transactions stored in the blockchain. Due to
some open issues such as pirate attacking, it was not possible
to entirely control this mechanism.
14 VOLUME 4, 2016
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10.1109/ACCESS.2020.2988579, IEEE Access
Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 6: Distribution with blockchain technology
Author Year Objective 1 2 3 4 5 6 7 Pros Cons
Kishigami
et al.
[98]
2015 To develop blockchain based digital content
distribution system
3 3 3 3 3 3 3 Access control mechanism, encrypted data in
blockchain with no authority; Permission based
control system
Pirate attacking
Hasan et
al. [99]
2015 Toachieve proof of delivery for digital values
by blockchain based smart contract
3 3 3 3 3 3 3 Immutable nature of ledger; audits from distributed
ledger
Lack of security, visi-
bility; corruption
Fotiou et
al. [100]
2016 To achievedecentralized naming based secu-
rity for data distribution
3 3 3 3 3 3 3 Hierarchical Identity Based Encryption, unique iden-
tification for content distribution over distributed net-
work
No Implementation
Kiy-
omoto et
al. [101]
2017 To anonymise dataset distribution platform
using blockchain
3 3 3 3 X3XDataset trading; peers and consensus mechanism for
verifying transactions
Privacy management
Feng et
al. [102]
2017 To develop a distributed and immutable me-
dia transaction framework
3X3 3 3 3 3 Self embedding watermarking algorithm; detection of
tampering and retrieval of original content
Reconstruction of me-
dia
Polyzos
et al.
[103]
2017 To discuss blockchain based information dis-
tribution for the IoTs
3X3X333Robustness, resilience Malicious gateways,
privacy threats
Chen et
al. [104]
2017 To create payment collection management
system using extensive bitcoin
3X3X333Privacy of data; undeletable transactions; reliability;
decentralized and tamperproof data
Counterfeiting;
lengthy block
generation process;
no technical extension
Sun et
al. [105]
2017 To develop model for central bank digital
money
3 3 3 X333Decentrality, tamper-resistance, traceability Privacy, supervision
and transaction speed
Wu et al.
[106]
2018 To enhance controllable efficient content
framework based on blockchain and ISO data
X3 3 3 3 3 3 High efficiency and scalability; low latency Lack of Interoperabil-
ity
Liu et al.
[107]
2018 To explore decentration transaction method
based on blockchain
3X3X333Decentralisation, safety, effectiveness,reliability, flex-
ibility
Limitations of Rules
and regulations, com-
puting power
Wang et
al. [108]
2019 A survey on blockchain in the intellectual
property
X3 3 3 X3 3 Comprehensive survey Scalability
1: Encryption system 2 : Digital rights management 3 : Peer to Peer authentication 4 : Content distribution 5 : Architecture 6 : Identity management 7 : Conditional
Access System
Table VI provides the detailed relative comparison of the
existing blockchain-based approaches in the digital content
distribution domain using parameters such as the objec-
tive, transparency, reliability, security, architecture, consen-
sus mechanism, traceability system, framework, immutabil-
ity of the blockchain, advantages, and drawbacks of the
existing approaches.
D. TOURSISM AND HOSPITALITY INDUSTRY
Tourism is the process of spending time to outside station,
i.e, away from our home for purposes such as business
purpose, personal purpose, relaxation and pleasure. Serving
travelers is the major functionality of the tourism Industry.
Nowadays, most of the people search and book their traveling
tickets, food, and lodging online with the use of the internet.
Therefore, the worldwide usage of the internet, the tourism
and hospitality industry has witnessed rapid changes. In this
digital world, many tourism companies like Expedia Group,
BCD Travel, Uber, Ola, and AirBnb have replaced their tra-
ditional business models by Consumer-to-Consumer (C2C)
models to achieve transparency and security in transactions.
There is a huge demand for innovative platforms in the
tourism industry, which can integrate technology, money, and
knowledge.
TUI and many other companies have already started us-
ing the blockchain for implementing the functionalities like
booking tickets and making payments. Many companies like
Expedia, CheapAir, Webjet, and One Shot Hotels use bitcoins
for the travel purpose, i.e, to book and reserve tickets. Digital
currencies simply integrate with smart contracts which have
enough potential to develop highly disruptive technologies
for the tourism industry. Authors of [109] suggested three
prepositions which helped to highlight some open issues in
the tourism industry. These prepositions mainly focus on
the customer’s point of view and market implementation’s
point of view. The prepositions include: I) New Type of
evaluation as well as review techniques which can build
trustworthy systems for rating purpose. II) The extensive
adoption of digital cryptocurrencies for C2C markets. III)
Use of blockchain leads to increase of disintermediation in
the tourism industry. In the case study part of our paper,
we try to highlight the above issues in the tourism industry.
The detailed explanation of the same is available in the case
studies section.
E. SMART HEALTHCARE
Health is the most valuable asset of any nation. In traditional
healthcare, all patient related data is stored in a centralized
way and therefore, it is not advisable to give access of
data to any untrusted third party. Moreover, the privacy and
security of patient information must be maintained as it
is vulnerable to a variety of attacks [133]. A centralized
architecture cannot fulfill these requirements completely.
Hence, smart healthcare is introduced to deal with the above
mention issues in conventional healthcare systems. Smart
healthcare focuses on monitoring and diagnosing patients’
health remotely through wireless communication channels. It
collects the necessary information of various patients through
heterogeneous wearable devices and sensors. Enormous data
is collected for a large number of patients. It is a big issue to
analyze and store this data in a secured manner. These data
should also be shared securely among trusted parties such
as hospitals, patients, doctors, and medical stores. Secure
communication of these data is pivotal as it affects important
decisions such as planning of new services in the hospital,
recommending doctors, analyzing symptoms of different dis-
eases or health issues, and improving the overall system to
make it intelligent.
Table VII provides a detailed relative comparison of the
state-of-the-art healthcare security standards used for smart
VOLUME 4, 2016 15
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 7: Worldwide State-of-the-art Healthcare Security Standards
Standard Year Country Objective Issuesconsidered Parametre’s Improved
123456789
HIPAA 1996 United
states
To assure security and privacy of health data 3XX333333
COBIT 1996 Australia To adopt information technology for electronic health information X33X33XXX
HITRUST 2007 United
states
To build a security framework to access, store and exchange sensitive
health regulated data
333333333
ISO 27799 2007 United
kingdom
To maintain requirements with applicable laws and regulations, prevent
unauthorized access and impinging to data
3X333X3X3
NIST CSF 2014 United
states
To restrict or prevent unauthorized access with implementing functions
like identity, protect, detect, respond and recover from hazards.
X X 333333X
DoD 8500 2014 United
states
To comply with information assurance certifications 3 3 X3 3 XX3 3
DISHA (Digital Information Secu-
rity in Healthcare, )
2017 India To protect from data breaches, restrict commercial usage of digital health
data, apply significant penalties for non-compliance
333333333
The Medical Device Cybersecurity
Act of 2017
2017 United
states
To secure medical devices or wearable health with cybersecurity X33333X3 3
The Internet of Medical Things Re-
silience Partnership Act (2017)
2017 United
states
To reduce the healthcare data breaches and avoidthe risk of cyber-attacks 333333333
NIS 2018 United
kingdom
To manage risks from security aspects, minimize the impact of hazard
incidents on essential services
X3333X333
[1] Lack of protected health information [2] The level of evaluation of risk factors [3] Access Management [4] security maturity [5] Information Security Incident Management
[6] Reduced cost and complexity [7] Human resources security [8] Efficiency,inclusiveness, timeliness [9] Improved healthcare compliance
healthcare. These standards are compared using the parame-
ters such as access management, security maturity, reduction
in cost and complexity, and improvement in healthcare com-
pliance. For the various medical research activities, deciding
treatments, and analyzing symptoms of diseases, patients’
data is required to be shared periodically. Traditional access
control policies are not secured enough to share highly sen-
sitive patient records from one party to another. Moreover, in
most of the cases, patients do not share their medical history
with the doctors [134],. In case of a medical emergency,
medical records of the patient are necessary, but the same is
not available due to poor record maintenance. All the above-
mentioned issues can be solved by smart healthcare using
Electronic Health Records (EHR). Though smart healthcare
is capable of solving the major issues in the healthcare
industry, there are some challenges to be addressed. Access
control policy for EHR, privacy, security, and availability, are
open issues in smart healthcare. The blockchain technology
can be used to get solutions to these issues. In fact, the
blockchain has the potential to support smart healthcare
through the distributed ledger among various users such as
patients, doctors, medical stores, and insurance agencies.
Authors of [110] proposed a blockchain-based intelligent
application commonly known as Healthcare Data Gateway
(HDG). Patients can securely share and control their data
through a secured data gateway. It processes and manages
patients’ data without any concern about the third party. HDG
consists of three layers namely Data Usage, Data Manage-
ment, and Storage. Entities that use healthcare data such
as physicians, companies, government, and researchers are
associated with the data usage layer. In the data management
layer, HDGs independently connected to each other. This
layer also manages all types of metadata such as patients’
data, schemas, and indices information. The storage layer
prevents the attacks on integrity and confidentiality by pro-
viding secure and scalable storage for the healthcare system.
Azaria et al. [111] developed a decentralized MedRec
model which was a novel data management system for large
scale EHR. In this proposal, confidentiality, authentication,
and accountability of health records were maintained via a
comprehensive log using blockchain-based MedRec model.
Authors of [112] developed a new architecture for the
medical field especially for precision medicine and clin-
ical trial. This architecture had four new components: I)
Blockchain-based parallel and distributed computing com-
ponent to examine parallel computing using data analytics,
II) Trustworthy information sharing component to enable a
trustworthy medical data system for collaborative research,
III) Application data management component to maintain the
integrity of data, and to integrate dissimilarity of medical
data, IV) Verifiable unknown identity management compo-
nent for maintaining identity privacy for IoT, person and
devices as well as secured access to patient-centric medicine
data.
Authors of [113] developed a reliable healthcare system on
the basis of Pervasive Social Network (PSN) using different
protocols. The first protocol was an extended version of IEEE
802.15.6 display authenticated association. It was used to es-
tablish secured links by means of unbalanced computational
requirements for mobile devices and resource-restricted sen-
sor nodes. Health data was shared between PSN nodes with
the help of the second protocol which was based on the help
blockchain technique. The authors examined the proposed
protocols and other factors for evaluating the performance.
The proposed system demonstrated the possibility of using
the blockchain technology, especially for PSN-based appli-
cations. Though the performance of the proposed system was
not measured on a mass-scale healthcare system, i.e, PSN-
based system, as stated by the authors, the performance of
the proposed system could be improved in terms of transport
and monitoring of the environment [135].
Authors of [114] discussed a viewpoint on the blockchain
founded healthcare data management system. They also be-
stowed a framework for sharing, managing EMR, especially
for the patients suffering from cancer. The proposed archi-
tecture included a user interface as well as the backend. The
backend comprised of the components such as membership
services, certification authority, clusters of nodes, load bal-
ancer, and distinct cloud storages for patients’ certificates and
data. This work substantially reduced turnaround time for
16 VOLUME 4, 2016
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10.1109/ACCESS.2020.2988579, IEEE Access
Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 8: State-of-the-art blockchain based approaches to secure healthcare 4.0
Author Year Objective 1 2 3 4 5 6 7 8 Pros Cons
Yup et al.
[110]
2016 To discover healthcare knowledge on blockchain
with privacy and danger control
3 3 3 3 3 3 3 3 Data controlled by patients Current system has
access control and
privacy issues
Azaria et
al. [111]
2016 To access medical data and permission manage-
ment using blockchain
X3 3 3 3 3 3 XAccessibility of medical records via a dis-
tributed ledger; patient data sharing
Heavy regulation
and bureaucratic
inefficiency
Shae et
al. [112]
2017 To implement the design over blockchain for clin-
ical trial and precision medicine
3 3 3 3 3 3 3 XEasy data sharing, transparency and trust Privacy issues, high
mortality and dis-
ability rate
Zhang et
al. [113]
2017 To secure a network for extensive social network
based healthcare
3 3 3 3 3 3 3 3 Distributed load, shared health data Computationally
limited devices, no
mature schemes
Dubovit-
skaya et
al. [114]
2017 To empower eHealth 3 3 3 3 3 3 3 XShared, immutable - transparent ledger; ac-
countability
Time delay for data
connectivity
Xia et al.
[115]
2017 To create trust-less medical data sharing among
cloud service providers with blockchain
3 3 3 3 3 3 3 3 Tamper-proof transactions, access control
mechanisms to detect violations of data
permissions
Lack of scalability,
data interoperability,
key management
Rifi et al.
[116]
2017 To exploreblockchain technology for eHealth data
access
3 3 3 3 3 3 X X Data sharing in secure, private, user-
centric, decentralized network
Huge amount of
data exchange; lack
of scalability and
interoperability
Liang et
al. [117]
2017 To attach blockchain for data sharing and collabo-
ration in mobile health usage
3 3 3 3 3 3 X X Secure Merkle root tree for transactions;
Data Sharing and Healthcare Collaboration
Lack of interoper-
ability
Magyar
et al.
[118]
2017 To solve the privacy and availability issues for
EHR data using blockchain
X33333X X Trust, security, speed, disintermediation,
distributed electronic health records
Exchangability,
integrity and
security, portable
user data
Al-
hadhrami
et al.
[119]
2017 To explore the feasibility of blockchain in health-
care
3 3 3 3 3 3 X X Easily organized data, consent manage-
ment
Sybil attacks
Jiang et
al. [120]
2018 To implement the blockchain system for health
data exchange
3 3 3 3 3 3 3 3 Combined off-chain storage and on-chain
verification for privacy and authenticity
Reduced system
throughput
and fairness,
complicated access
control
Theodouli
et al.
[121]
2018 To design a system for smooth healthcare data
sharing
3 3 3 3 3 3 3 XPatient Data Integrity, Workflow automa-
tion, Auditing and accountability
Pseudonymity,
single point of
failure
Zhang et
al. [122]
2018 To support flexible queries with access control to
EMRs
3 3 3 3 3 3 3 3 Access management without reveling
unauthorized users
Privacy control man-
agement
Li et al.
[123]
2018 To explore data protection system for health data 3 3 3 3 3 3 3 3 Tamper-proof cryptographic solutions High probability of
record damage; Slow
confirmation; Small
storage space
Fan et al.
[124]
2018 To strengthen efficientand secure health data shar-
ing with blockchain network
3 3 3 3 3 3 3 3 Data management and sharing from EMR
systems; privacy preservation
huge computation
power
Wang et
al. [125]
2018 To secure EHR system with cloud and attribute
based cryptosystem and blockchain
X3333333Identity based encryption for database; as-
sured integrity and traceability
Deployment is not
available
Radanovic
et al.
[126]
2018 To explore the opportunities for blockchain tech-
nology in medicine network
X33333X X P2P network, decentralization of database,
security through cryptography
lack of knowledge of
technology
Kaur et
al. [127]
2018 To explore the future of blockchain based hetero-
geneous medicare information in cloud
3 3 3 3 3 3 3 XHash based ledger, P2P network Enterprise data
warehouse
Griggs et
al. [128]
2018 To develophealthcare system with smart contracts
for secure automated remote patient monitoring
X3 3 3 3 3 3 XReal-time patient monitoring, automation
in delivery of notifications with HIPPA
compliance
Lack of large-scale
key management;
delay in response
time
Guo et al.
[129]
2018 To secure ABE scheme with multiple authorities
for blockchain in EHRs
X3333333Immutability of the information ledger Lack of interoper-
ability, privacy
Uddin et
al. [130]
2018 To explore continuous patient monitoring with pa-
tient centric agents
3 3 3 3 3 3 3 3 Lightweight encryption and authentica-
tion, tamper-proof, protection against sin-
gle point of failure
End-to-end delay
Sun et al.
[131]
2018 To explore decentralizing attributebased signature
for healthcare with blockchain
X3333333Verifiable, secure sharing of large-scale
and distributed EHR, anonymity, and non-
repudiation
Attribute certificates,
storage capacity
Khezr et
al. [132]
2019 explore recent blockchain technologies deployed
in Healthcare, and analyzes their strengths and
weaknesses
333X3 3 3 3 QTUM Privacy issues
Bhat-
tacharya
etal. [60]
2019 Integration of Blockchain and deep learning to
secure EHR
3 3 X33333CordaDApp Medical data Shar-
ing
1 : Architecture 2 : Data integrity 3 : Medical data sharing 4 : Access control 5 : Distributed electronic health records 6 : Patient encryption key 7 : Simulation tool /
Framework 8 : Algorithm
EMR sharing, increased the power of decision making for
the sake of medical care, and also reduced the overall system
cost. The proposed system also guaranteed the availability,
security, privacy, and access control across the EMR data.
Xia et al. [115] developed a trustworthy blockchain-based
system called "MeDShare" especially to handle the chal-
lenges of maintaining voluminous medical information on
a cloud using big data for data provenance. Activities such
as sharing and transition of information were recorded and
stored in a tamper-proof manner. The authors also compared
the performance of "MeDShare" with the existing methods of
data sharing and came up with the conclusion that auditing
and data provenance could be achieved by cloud service
providers through the MeDShare. Risk factors of data privacy
were also minimized through the proposed system, but issues
such as scalability, data interoperability and key manage-
ment were not highlighted in the paper. Rifi et al. [116]
discussed the important problems such as scalability and
interoperability, and highlighted the advantages of including
the blockchain technology for medical data exchange to
achieve the best performance.
Liang et al. [117] developed a user-driven health infor-
mation sharing solution to handle the issues of privacy and
identity management. To address these issues, they suggested
VOLUME 4, 2016 17
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
the use of the channel formation scheme and membership ser-
vice of the blockchain. The authors also proposed a mobile-
controlled system based on hyperledger fabric with the use
of permissioned blockchains. The proposed work majorly
focused on the validation of the network nodes, and the
preservation of healthcare-related data.
A new blockchain-based information model was proposed
by Magyar et al. [118]. This model basically integrated com-
plex Electronic Healthcare Data (EHD). The implementation
of a decentralized and purely expendable network was possi-
ble due to the use of cryptographic tools and the blockchain.
The model was developed by considering the basic beliefs
of the HIPAA regulation existing in America. The proposed
work ensured information availability and resolved the issue
of data privacy at the same time, although the authors did not
provide any algorithm or method to handle the EHD related
issues such as integrity, security, portable user-owned data,
and interoperability.
Jiang et al. [120]focused on the fact that everyday huge
number of healthcare-related data are produced by individu-
als and hospitals. This data is very beneficial in the medical
industry for various purposes. It is quite challenging and
important to store this data securely. It is must to have
mechanisms to maintain confidentiality, privacy and integrity
of data. By keeping these requirements in mind, the authors
developed a BLOCkchain-based model for Healthcare In-
formation Exchange(BlocHIE), which resolved the above-
listed issues. In this mechanism, they considered two types
of healthcare-related data - personal healthcare related data
and electronic medical records. They performed analysis
of various ways and requirements to share and store the
healthcare related data. The framework was based on two
blockchains which were loosely-coupled and one was an
EMR-chain and the other was a data-chain. Different meth-
ods and techniques of chain verification, as well as storage,
were integrated to ensure authentication and privacy. The
authors also developed two transaction packaging algorithms
such as TP&FAIR and FAIR-FIRST for PHRD-Chain and
EMRChain respectively, which increased the fairness, effi-
ciency, and system throughput among the users. These two
packaging algorithms were evaluated in terms of throughput
and fairness using the BlocHIE mechanism. As claimed by
the authors, the FAIRFIRST algorithm increased the fairness
and the TP&FAIR algorithm increased the throughput.
Nowadays the blockchain is being used worldwide in the
medical field to maintain and store the healthcare related data
securely. Theodouli et al. [121] said that this data could be
used for further innovation and research in the healthcare
industry. By considering the needs of the healthcare industry,
the authors of [121] proposed a design architecture for a
system which can easily secure permission management and
data sharing for the healthcare with the help of the blockchain
features. The proposed infrastructure consisted of three lay-
ers: Web/cloud platform layer, Cloud middleware layer, and
Blockchain network layer. As shown in the paper, this model
could help to enhance security and integrity to a good extent.
FIGURE 8: Blockchain in smart healthcare
This model was also used in the KONFIDO project to verify
the parameters such as interoperability and data exchange.
According to the authors, and the proposed model gave ad-
ditional benefit with respect to workflow automation, patient
pseudonymity, accountability, auditing, and data integrity.
Fig 8, gives an idea about the use of blockchain technol-
ogy in smart healthcare. Table VIII provides a detailed rela-
tive comparison of the existing blockchain-based approaches
for smart healthcare. Parameters used for this comparison are
the objective, security, architecture, simulation tool or frame-
work, hardware, and physical design, benefits and drawbacks
of the existing approaches.
F. SMARTCITY
In smart city implementations, heterogeneous sensors are
used by various smart devices and users to collect the re-
quired data. These data are processed and used in traf-
fic management, transportation systems, waste management,
schools, libraries, water supply networks, community ser-
vices, and power plants to improve the performance. There
is a gradual increase in the number of people living in city
areas. Due to increased use of the Internet, big data [145],
[146], and IoT, the concept of a smart city has become
very popular. To strengthen the development of the smart
cities, we need effective mechanisms to solve the existing
problems related to energy, transportation, governance, and
environment. Some open issues such as deficient security in
IoT, difficulty in maintenance and upgradation of equipment,
maintaining the trust among the internet users, optimizing the
cost of running data centers, damage resistance, privacy, and
security need to be addressed to deploy smart city projects
effectively and efficiently. According to the authors of [142],
the blockchain technology is the potential of solving all these
problems and hence, it is best suited for developing smart city
solutions.
As we know, the consumption of energy increases due to
urban development. The purpose of the internet is to develop
an intelligent energy system. Authors in [142] mainly fo-
cused on how the blockchain could help to solve the problems
in the internet, big data, and IoT [15], [16]. In this research,
issues such as user’s creditability, the creditability of the data
in the central database, data privacy protection, and privacy
18 VOLUME 4, 2016
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 9: Smart city development with blockchain technology
Author Year Objective 1 2 3 4 5 6 7 8 9 Pros Cons
Biswas et
al. [136]
2016 To secure smart city with blockchain tech-
nology
3X3X33333Resilient with attacks, reliable, better
fault tolerance and well planned op-
erations
Interoperability, scalable
network
Rivera et
al. [137]
2017 To explore how digital identity can help
smart city with blockchain
3X3 3 XX3 3 3 Transparent, decentralized, hashed
secure blocks
Implementation not done
Liao et al.
[138]
2017 To design a lottery system for smart city
with the help of blockchain network
33333X3X3Transparency,fairness, privacy Connectivity, integration of
service
Lazaoiu et
al. [139]
2017 To combine IOT and blockchain in smart
district development
333X33333Automation model for smart home Interoperability of home
devices
Sharma et
al. [140]
2018 To develop a hybrid network architecture
for the smart city
333X33333Proof of work adoption, hybrid ar-
chitecture
High latency and band-
width; lack of scalability
Batty et al.
[141]
2018 To analyze the transformational effect of
blockchain and IOT in smart cities
333X333X3Improved infrastructure Lack of interoperability, re-
silience, common gover-
nance, secure digital envi-
ronment
Shuling et
al. [142]
2018 To explore applications of blockchain in
smart city infrastructure
3333333X3Redundant storage and distribution High cost, poor recovery
capability, maintenance of
IoT equipment.
Salha et
al. [142]
2019 To explore integration of blockchain and
smart city
33333X3X X Reduced transaction costs Lack of clarity during the
implementation
Yetis et
al. [143]
2019 Toresolve security constraints in smart city
through blockchain
333XXX3X X Authentication process is discussed
in depth
Results can be executed on
large scale
Hakak et
al. [144]
2020 To securing smart cities through
blockchain
333X3X3 3 3 Fast and realtime processing of trans-
actions
Robust blockchain archi-
tecture
1: IOT 2 : Software defined network 3 : Security 4 : Digital identity 5 : Architecture 6 : Smart energy 7 : Smart parking & automation 8 : Smart traffic 9 : Green
environment
protection of data were addressed. In the proposed work, the
blockchain identified valid IoT nodes and denied the system
access by malicious nodes. It also maintained data privacy in
IoT and improved storage and computing abilities with the
help of decentralized databases. As shown in the paper, the
proposed work effectively prevented various attacks on the
network infrastructure with improved recovery mechanism in
big data [147].
Various architectural issues in the network infrastructure
of the smart city were discussed by Sharmaet al. [140]. Due
to the exponential rise in information volume as well as the
increase in the count of connected IoT devices, different
issues such as bandwidth, security, latency, and scalability
emerge in the existing smart city frameworks. To address
these issues, authors in [140] proposed a hybrid architecture
for a smart city. It was divided into two partitions: edge
and core network through the hybrid architecture scheme.
Moreover, this architecture was developed by considering
all the strengths of the distributed as well as centralized
architectures. In this paper, the authors also suggested the
PoW scheme to strengthen privacy and security. They sim-
ulated the proposed model by evaluating feasibility and
performance based on different performance metrics such
as latency, and throughput. Authors also came up with a
software-defined networking (SDN) and blockchain-based
hybrid network architecture, although they did not focus on
important parameters like how to deploy edge nodes, how
to enable the caching technique at edge nodes etc. Due to
this research gap, there is a tremendous scope of work in this
domain in the near future.
Biswas et al. [136] proposed a four-layer security based
framework which was developed using the decentralized
blockchain technology. It was integrated with smart devices
that provided a secure and trustworthy communication model
for a smart city. The proposed framework comprised of four
layers- the physical layer, communication layer, database
layer, and interface layer. In the physical layer, multiple
standards were defined for smart devices using which data
collected could be shared and integrated. The blockchain pro-
tocols were used to integrate with the communication layer
to provide privacy and security of the transmitted data. The
authors also suggested that the extensive use of the private
ledger could lead to the improvement in performance, effi-
ciency, and security for various real-time applications such
as smart parking of vehicles, smart cleaning, smart home,
and traffic control system in a smart city [148]. Scalability
achieved by this framework was also up to the mark. As
shown in Fig. 9, the proposed model had good features like
fault tolerance, reliability, capability, and faster execution
of the operation. Due to the use of the blockchain, various
smart devices were able to communicate in a distributed
environment. The major gap found in this paper is that
the proposed model not missed to focus on some of the
important issues like scalability and interoperability of the
heterogeneous platforms.
Rivera et al. [137] defined a smart city as the use of
information technology (IT) to make the life of citizens more
better and comfortable [139]. A smart city is a digital world
which interconnects various areas such as government of-
fices, schools, healthcare, colleges, and the economy. Nowa-
days, the unique identity of users is the biggest concern in
business and smart city environments. Many researchers and
developers have attempted to develop a reliable technology
which can accurately determine the users’ identities. These
attempts have used various attributes such as name, address,
health status, hobbies, and credit record of the users. The
digital identity is significantly important as it plays a vital
role in security measures for interconnected devices in a
smart city. The authors of [139] failed to highlight some of
the important issues like smart energy, architecture, and SDN
based security in the development of a smart city.
In [138], Liao et al. focused on some important issues of
smart cities like interoperability and transparency of various
services. Due to the advancement in technology, fair and
transparent services are demanded by the citizens in a smart
city. Lottery game is an important segment in a smart city
application, but it has a deficiency in terms of fairness and
transparency. Therefore, the authors of [138] came up with an
VOLUME 4, 2016 19
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
FIGURE 9: Framework for smart city
optimal solution to improve the transparency and fairness of a
lottery system. They designed a blockchain-based transparent
lottery system for a smart city. The authors proposed a three-
layered blockchain-based lottery system known as FairLotto
which used four lightweight protocols. Closing time, lottery
purchase, initialization, and verifying winning numbers were
the four different lottery stages in the proposed system.
Equal possibility of winning the prize for each and every
participant was guaranteed by this four-layered architecture.
FairLotto effectively ensured transparency and did not store
any financial transactions in the blockchain. Due to this,
the transactional privacy was preserved and fairness and
transparency were achieved in the lottery system. However,
there was a lack of connectivity and service integration in
the lottery system. Moreover, the authors also implemented
Fairlotto system in Ethereum, but the results of the numerical
analysis on the performance were not provided. These two
were the major research gaps in the proposed work.
Table IX provides a detailed relative comparison of the
existing blockchain-based approaches for smart city applica-
tions. We use parameters such as the objective, digital iden-
tity, security, architecture, smart energy, smart parking and
automation, smart traffic, green environment, advantages,
and drawbacks of the existing approaches for making this
comparison.
G. BUSINESS
The Blockchain is a decentralized technique used for the se-
cured exchange of cryptocurrency and financial transactions.
Each user maintains its distributed ledger which is useful for
validating a new transaction. Bitcoin is a medium of digital
cryptocurrency that provides transactions in a secured and
distributed environment. The group of all executed bitcoin
transactions performed in the past is called a distributed
ledger. After every successful transaction, an authentic user
has to make changes in the distributed ledger which is
distributed over the network and shared by all users in the
network. As hash functions are used in the formation of
the blockchain, data integrity, confidentiality, and privacy are
maintained across all the transactions.
Singh et al. [149] discussed the importance of blockchain
in business, banking, and financial applications. It has enough
potential to reorganize the business market industry. Use
of block-chain reduces the risks, cost, probability of cyber
attacks in financial organizations, and precise auditing of
organizations can be achieved. Authors simply discussed
the use of blockchain in the business application is highly
desirable and convenient, due to its characteristics. They did
not suggest any basic architecture for a business application
to overcome the problems of blockchain like interoperability
and scalability.
Nguyen et al. [150] discussed that sustainable develop-
ment in finance can be achieved through the inclusion of
the secured blockchain. This technology could bring various
benefits for the existing banking system as well as society.
It could increase the speed and efficiency of execution, opti-
mize the transaction time and networks of record keeping,
reduce the cost of financial transactions, and improve the
probable chances of accessing the financial market. Nowa-
days, still there are no complete legal rules and regulations
for cryptocurrencies and bitcoins. Hence, the use of the
blockchain is a big challenge in the payment industry.
Rimba et al. [151] provided a comparison of cloud ser-
vices and blockchains for Business Process Execution (BPE).
Based on the experimental results, the authors showed that
the cost of Ethereum based process execution is higher as
compared to the cost for business process execution on Ama-
zon SWF, but authors ignored to formulate a method which
could estimate the execution cost depending on the model as
well as data collected in the past. Moreover, this paper did
not describe how to minimize latency and execution cost.
Lundbak et al. [152] discussed that consensus and trust
could be achieved in a distributed network through the
blockchain. Thus, many private and governmental sectors,
central banks, insurance and finance agencies, academic
institutions, and especially some startups in Europe focus
on the implementation of the blockchain in their routine
operations. Improper implementation of the blockchain may
lead the industrial standards and agendas to non-secured op-
erations. The authors of [152] devised an oligarchic approach
to authenticate and secure business processes and data. Their
approach shared the business data without exposing the sen-
sible information and resolved numerous issues of game-
theoretic mining but it was not able to prevent uncertain
behavior such as cheating.
The authors of [153] described an algorithm to ensure data
confidentiality in an untrustworthy environment. This algo-
rithm translated the Business Process Execution Language
(BPEL) into a highly confidential smart contract, but this
algorithm did not meet the basic security pillars such as data
integrity, correctness, and authenticity. The implementation
of the blockchain may help to resolve the above-mentioned
issues.
Johng et al. [154] presented a framework to improve
the trust in business processes using the blockchain. This
framework mainly focused on issues like transparency and
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
immutability. It also improved the trust among different
stakeholders. Though the framework was not capable of
resolving issues like traceability, the authors tried to build
a process meta-model for supply-chain through the same
mechanism.
An end-to-end model for Real Time Gross Settlement
(RTGS) through hyperledger fabric blockchain platform was
designed by the authors of [155]. The proposed system made
the payment service more secure and efficient. It used a
timestamp algorithm which resolved the problem of gridlock
and the risk of privacy. This framework was not generic for
diverse payment services. A more generic platform can be
developed through the blockchain technology [156], [157].
Mendlinget al. [158] discussed the execution of busi-
ness processes beyond organizational boundaries through the
blockchain without the inclusion of any trusted third party,
although the authors did not explain how to resolve the
existing issues such as latency, bandwidth, throughput, and
size in the proposed work.
Table X provides a detailed relative comparison of the ex-
isting blockchain-based approaches for the business domain.
Parameters used for this comparison are Business Process
Service(BPS), trust management, security, architecture, con-
sensus mechanism, cost model, monetary policy, pros, and
cons of the existing approaches.
H. INTERNET OF THINGS
In the Internet of Things (IoT), various devices are connected
through the internet to share useful information via servers
for performing specific tasks or actions in the external en-
vironment such as measuring temperature or humidity and
moving of shaft. Delivering the right information to the right
people at the right time is possible through the use of IoT.
Various sensors continuously sense the data and these col-
lected data can be used for effective decision making. Things
connected to the internet are expected to cross 50 billion
in the near future, which is basically an approach of how
these various devices should be designed and integrated with
each other, so as to deliver a service delivery network, which
can serve the needs in the future. The architecture of IoT is
basically the backbone of any application and thus, it should
be crafted carefully considering the needs of the evolution
of functionality, scalability, availability, and maintainability.
From this IoT architecture model, it is very clear to know
that security is an essential factor in all IoT layers as shown
in Fig. 10.
Nowadays, most of the IoT devices are not fully secured
and can be easily hacked. These devices have restricted
network capacity, limited computation power, and small stor-
age capacity. Due to these characteristics, such devices are
vulnerable to a variety of attacks as compared to computer
systems. Samaniego et al. [162] observed that the issues of
network latency occurred due to cloud-centric IoT systems.
To overcome these problems, they developed a software-
defined IoT management construct known as Virtual Re-
sources (VR). Tamper-proof, decentralized blockchains have
FIGURE 10: IoT architecture model
the potential to solve security issues in any IoT Implementa-
tion. To use the blockchain as a service for the IoT, hosting
environment is one of the challenges. Edge devices have
limited computational resources as well as bandwidth, thus
making fog or cloud as the potential hosts [163].
The authors of [164] surveyed and categorized some im-
portant IoT related security challenges and requirements. The
same were tabulated and mapped against the existing state-
of-the-art solutions. The authors suggested the integration
of the blockchain as a key solver for such challenges and
also outlined the research issues which must be addressed
in future, that could provide scalable, reliable, and efficient
security solutions for the IoT.
Singh et al. [165] observed that the current security tech-
nologies do not have the potential to secure IoT applications
from various cyber-attacks in the business domain. They also
suggested three different patterns of the blockchain-based
security model for the IoT. There are various distributed
ledger protocols suitable for the IoT Implementation such
as hyperledger fabric, Ethereum, and Internet of Things
Application (IOTA) [166]. In this paper, the performance of
these protocols was compared for the development of IoT
applications. The authors also presented three different archi-
tectures for the same. The architectures differ in the position
of key storage and Ethereum blockchain which enhanced
the security and reduced the network traffic. The problem
with these architectures was that they were not capable of
VOLUME 4, 2016 21
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Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 10: Business in blockchain technology
Author Year Objective 1 2 3 4 5 6 7 Pros Cons
Nguyen et
al. [150]
2016 To develop sustainable financial tech-
nology with blockchain with business
model
3 3 3 X333Faster, efficient, time optimized solution; reduced cost;
access managment
Incompleteness of legal
regulations
Singh et al.
[149]
2016 To explore future of finance in
business and cyber security with
blockchain technology
3 3 3 X333Encrypted ledger; tamper-proof; decentralized registry Lack of interoperability,
scalability
Rimba et
al. [151]
2017 To execute business process model
with blockchain
3 3 3 3 3 3 XCross-organisational, computational cost model High latency, cost
Lundbak et
al. [152]
2017 To control oligarchic business to busi-
ness blockchains
3 3 3 X333Game-theoretic mining incentives, immutability, secu-
rity, anonymity
Trustworthiness,
Carminati
et al. [153]
2018 To secure confidential business pro-
cess execution on blockchain
3 3 3 3 3 3 XTrust, transparency, and accountability over business
processes
Serious consequences on
confidentiality and pri-
vacy
Johng et al.
[154]
2018 To increase transaparency of business
process in blockchain
3 3 3 3 ✕ 3✕ Distributed database, traceability, immutable ledger Lack of trust, traceabil-
ity and transparency
Wang et al.
[155]
2018 To developinter bank payment system
on business enterprise blockchain plat-
form
3333333Distributed trust, confidentiality, gridlock resolution and
reconciliation
High costs in centralised
system lack of security
and recovery.
MENDLING
et al. [158]
2018 To manage the business process man-
agement in blockchain technology
3 3 3 X333No single point of failure Throughput, Latency,
Size and bandwidth
Oak et al.
[159]
2018 To create smart collaboration mecha-
nism in business using blockchain
3 3 3 3 3 3 XSmart contracts, collaborations, social network-
ing,Consensus, Authentication, Secure Release, Non
Repudiation
Increased Latency, In-
creased Traffic, Com-
plexity
Konstan-
tinidis et al.
[160]
2018 To review business applications of
blockchain technology
33333X3Smart collaboration, authentication Complexity
Attaran et
al. [161]
2019 Toexplore the business applications of
blockchain technology
3 3 3 3 3 3 XTransparency Privacy issues need to
explored in detail
1: Business process service 2 : Trust management 3 : Security 4 : Architecture5 : Consensus transaction mechanism 6 : Cost model 7 : Monetary policy
monitoring the IoT devices’ transactions automatically.
Huh et al. [167] developed a new way to manage a
few numbers of IoT devices with the use of Ethereum and
computing platform. They used three Raspberry Pis, and
smartphones and proposed three smart contracts which used
public keys and signatures to track meter values and save
the values of light bulbs and air conditioners. Malicious
attacks on smart contracts could be detected and ignored by
the computing systems of light bulbs and air conditioners.
However, the proposed work failed to resolve issues such
as Denial of Service (DoS) and synchronization. Moreover,
the proposed mechanism considered a small number of IoT
devices and thus was unable to implement a full-fledged IoT
system for multiple devices.
Liao et al. [168] presented various design issues and an
architectural approach for the blockchain-based IoT services.
Design decisions could be carried out by developers with the
help of this architecture. Unfortunately, the proposed work
failed to show the adverse effects on architectural attributes
like robustness, efficiency, and security.
Reyna et al. [169] analyzed the major challenges of IoT
Integration such as scalability and storage capacity, data
privacy and anonymity, and consensus mechanisms. They
identified the potential benefits of the blockchain for the IoT
and also suggested different topologies for the integration.
Some key points to enhance the performance and feasibility
of IoT applications with the help of the blockchain was also
discussed in the paper.
Table XI provides the detailed relative comparison of
the existing blockchain-based approaches for the IoT. This
comparison has been done using parameters such as reli-
ability, encryption, security management, edge computing,
architecture, consensus mechanism, threat model, framework
implementation, advantages, and disadvantages of the exist-
ing approaches.
I. MANUFACTURING
The process of manufacturing includes several elements such
as operations management, asset management, intelligent
manufacturing, planning, the interaction of humans and ma-
chines, performance optimization, performance monitoring,
and end-to-end operational visibility.
Li et al. [183] stated that the IoT has converted the conven-
tional manufacturing processes into a smart manufacturing
process. The IoT enabled manufacturing is far smarter and
efficient than cloud manufacturing, as it speeds up the flow
of production especially in the manufacturing plant, man-
agement of inventories & warehouses, and observation of
development cycles by using IoT devices. Due to this, most of
the manufacturing companies have invested crores of funds
in the implementation of the IoT applications. The use of
the IoT in the field of manufacturing and logistics will rise
to 40 Billion by 2020 [188]. Due to the characteristics of
the IoT such as greater energy efficiency, predictive main-
tenance, higher product quality, reduced downtime, speed,
and more informed decisions, it has various applications in
the manufacturing plants [191]. As we know, energy is one
of the largest expenses for manufacturing Industry, energy
efficiency must be achieved which can be done through IoT
based smart manufacturing.
The authors of [185] proposed a trusted FabRec proto-
type, which linked physical devices and various computing
nodes through a decentralized platform. In this prototype,
transparency was ensured through audit trails. In the de-
centralized network, the authors developed smart contracts
for the autonomous interaction of nodes in the absence of
human involvement. The proposed architecture used a proof
of concept linked with the nodes and physical devices and
enabled smart manufacturing. Cloud-based manufacturing
basically use the centralized networks which have problems
such as security, flexibility, availability, and efficiency.
To resolve such issues, the authors of [183] discussed and
22 VOLUME 4, 2016
This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/.
This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI
10.1109/ACCESS.2020.2988579, IEEE Access
Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
TABLE 11: Internet of things in blockchain technology
Author Year Objective 12345678Pros Cons
Samaniego
et al.
[162]
2016 Tohost virtual IoT resources on edge devices
with blockchain
3333X333Safe and secure approach for data
management of IoT nodes
Constrained interactions
Samaniego
et al.
[170]
2016 To developblockchain as service in IOT 3X33X333Tamper-proof storage of approved
transactions, distributed and decentral-
ized ledger
Hosting location
Khan et
al. [164]
2017 To review IOT security and its challenges
with blockchain solutions
33333333Ownership of keys, Distribution and
re-issue of keypairs, access control
Jamming adversaries, Insecure
initialization, Insecure physi-
cal interface, Buffer reserva-
tion attacks
Singh et
al. [165]
2017 To enhance security of IOT data in
blockchain
333X3333Shared ledger, cryptography, consen-
sus, smart contract
Access control
Pustisek
et al.
[166]
2017 To develop front end IoT based blockchain
application using Ethereum
333X3333Reduced network traffic and enhanced
security, Front-end application parts,
On-chain business logic
Location and synchronisation,
trusted transaction, data vol-
umes
Huh et al.
[167]
2017 To manage IoT Devices using Blockchain
Platform
3X33X333Smart contract, Ethereum model, en-
cryption
Synchronization, configuration
Liao et al.
[168]
2017 To discuss design problems and architectural
styles for blockchain based IoT services
3X333333Mechanisms for cyber-physical inte-
gration
Locations of blockchain end-
points
Reyna et
al. [169]
2018 To explore blockchain and its integration
with IOT
33333333Secure code deployment, reliability,
autonomy, identity,decentralization
Storage capacity and scalabil-
ity, threats, data privacy
Qian et al.
[171]
2018 To enhance decentralised IOT security with
blockchain approach
33333333Decentralisation, light weight encryp-
tion methods
Identity verification, Abnormal
network traffic
Hammi et
al. [172]
2018 To implement decentralised blockchain
based authentication system for IOT
3X3X3333Threat model, resiliency toward at-
tacks, spoofing attack protection, mes-
sage replay protection, DoS/DDoS
protection
Not adapted to real time ap-
plications, initialization phase,
Evolution of cryptocurrency
rate
Minoli et
al. [173]
2018 To develop Blockchain mechanism for IOT
security
33333333Global shared trust, firewalls, encryp-
tion, trusted execution environment,
authorization, authentication, and ac-
counting
Practical level, implementation
of topology
Novo et
al. [174]
2018 To create design for scalable access manage-
ment in IoT
33333333Merged-mined, backward compatible
virtual machine
Expiration date parameter in
smart contract
Han et al.
[175]
2018 To evaluateblockchain for IOT 3X3X X 333Energy greediness Compatibility service manage-
ment, scalability
Kataoka
et al.
[176]
2018 To develop distributed IoT traffic manage-
ment with the help of blockchain and SDN
network
33333333Automation for implementation of IoT
traffic management, Trust List realistic
deployment
Trustability and Authenticity,
Scalability and Coverage
Agrawal
et al.
[177]
2018 To keep continuous security in IOT using
blockchain
333X3333Immutable and decentralized nature,
intangible and unquantifiable security
Lack of trust, single point of
failure
Ismail et
al. [178]
2019 To reviewthe potential of blockchain Archi-
tecture and Consensus
3XXX3333In-depth survey discussed various con-
sensus algorithms
Scalability of the IoT network
Shi et al.
[179]
2019 To provide comprehensive survey on data
sharing among trusted stakeholders in IoT
33XXX33XDecentralized consensus Security flows in smart con-
tract
Park et al.
[180]
2020 To provide comprehensive survey on
blockchain technology toward green IoT
33X3333XImmutability in the transaction NA
1: Reliability, 2: Encryption, 3: Security management, 4: Edge computing, 5: Architecture, 6: Consensus transaction mechanism, 7: Threat model, and 8: Framework
TABLE 12: Manufacturing with blockchain technology
Author Year Objective 1 2 3 4 5 6 7 Pros Cons
Zhang et al.
[181]
2017 To analyse operational ways of smartfactory and its
costlier devices of manufacturing in the Internet
3 3 3 3 3 3 3 Blockchain-based collaborative manufactur-
ing model, demand management
Operation manage-
ment strategy, liq-
uidity problem
Backman et
al. [182]
2017 To explore 5G network broker with blockchain to
allow automation of manufacturing devices
3 3 3 3 3 3 3 Security enhancement, trust layer, efficient
ecosystem, consensus mechanisms
Privacy
Li et al.
[183]
2018 Todevelop cloud manufacturing system on blockchain
technology
3 3 3 3 3 X X Improved security and scalability Public-based
Li et al.
[184]
2018 To explore cloud based manufacturing with
blockchain to secure knowledge sharing for injection
mould redesign
3 3 3 3 3 X3Secure and trusted network Needs different
Implementation
and development
for different
applications
Angrish et
al. [185]
2018 To explore case studies on blockchain in manufactur-
ing
X3X3X3 3 Proof of concept system for all physical de-
vices, smart manufacturing and design
Lack of infrastruc-
ture
Barenji et
al. [186]
2018 To discuss blockchain based cloud manufacturing
shop floor and its machine level
3 3 3 3 3 3 3 Transformation of industry to service ori-
ented, combined and unique manufacturing
Machine level data
sharing
Kobzan et
al. [187]
2018 Toapply blockchain technology in industrial manufac-
turing with network simulation
X3 3 3 3 3 3 Better solution Heterogeneity
of mechanisms,
scalability
Mondragon
et al. [188]
2018 To explore the quality of blockchain in build up man-
ufacturing in mixed industry
X3 3 3 3 3 3 Reduction in lead times; tamper-proof pro-
cesses, transportation, storage and prove-
nance
Implementation
and low maturity
of blockchain
Lee et al.
[189]
2019 To apply blockchain enabled Cyber-Physical System
architecture for Industry 4.0 manufacturing systems
3 3 X3 3 3 3 Efficient performance Scalability
Stefan et
al. [190]
2019 To explore blockchain in additivemanufacturing X3 3 X X X 3Enough security Operation manage-
ment strategy
1 : Cloud based 2 : Peer network scalability 3 : IOT 4 : Security 5 : Architecture 6 : Simulation/Framework7 : Smart contract
VOLUME 4, 2016 23
This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/.
This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI
10.1109/ACCESS.2020.2988579, IEEE Access
Bodkhe et al.: Blockchain for Industry 4.0: A Comprehensive Review
developed a blockchain-based distributed network architec-
ture known as BVmfg. This architecture had a total five layers
which improved the trust between the service providers and
users for secured service sharing. The authors evaluated the
performance of BCmfg a case study in which for fifteen end
users and five service providers, scalability, and security were
improved. Later, the authors revised their prototype and de-
veloped a shop floor and machine level data sharing prototype
[186]. Authors used a public blockchain for shop level and
a private blockchain for service providers through which im-
portant data is collected and gathered. The new prototype was
level 2 Point-to-point (P2P) network implemented through
the blockchain. It handled cloud manufacturing challenges
like security and centralization effectively.
The authors of [184] proposed a blockchain and private
cloud based manufacturing four-layer knowledge sharing
system for Injection Mould Redesign (IMR). This work pro-
vided the rules and standards for the secured implementation
of the system in a trusted environment. It also provided a
knowledge sharing mechanism for the owners through which
their data, as well as assets, could be shared securely among
them. The system used the k- nearest neighbor retrieval
method which improved the efficiency of the search process.
The proposed model was limited to only some applications
and not fully developed for many applications. The au-
thors of [187] investigated various industrial requirements
such as scalability and adaptability of the network with the
implementation using OMNeT++ network simulator. Their
approach was efficient up to the first fourteen participating
lines and no uncertainty was identified.
Table XII provides the detailed relative comparison of the
existing blockchain-based approaches for manufacturing us-
ing the parameters such as scalability, architecture, security,
simulation/framework, smart contract, pros, and cons of the
existing approaches.
J. AGRICULTURE
In recent times, various issues related to food safety have
been observed. Higher use of fertilizers and pesticides on
agricultural products is the major concern in food safety.
Pesticides and fertilizers residues on various agricultural
products have caused world-wide concern [197]. Due to this,
there is a huge demand for safe agricultural products in the
market. To fulfill this demand, we need secured solutions
for handling the perfect tracing and management of the pro-
duction, wholesale, logistics to retail, production standards,
certifications, and business reputation [198].
Hua et al. [193] proposed a blockchain-based agricultural
tracking system, which was basically a decentralized system
in order to solve the trust crisis in the domain of supply-
chain. This blockchain-based agriculture platform recorded
the information about the production, storage, transporta-
tion, processing, distribution and supply-chain of agricultural
products for the third parties like government, insurance
companies, customers, and banks. The platform recorded all
the agriculture product related information on the blockchain
structures, as it could involve different users such as com-
panies, agencies, banks, or government to work together.
By considering the requirements, the authors developed an
agricultural traceability system for the same. This system
considered the fertilizers, pesticides, companies, seeds, agri-
cultural operations, time, and residue testing. According to
the authors, it was a very tedious task to build a platform
having a uniform structure, which considered all the complex
information and eliminated the possibility of the redundancy
in data. Hence, the authors designed two related structures
especially for the basic planting information as well as
for provenance records. Planting information included the
source production information in terms of identity, species
name, planting-time, company-name, greenhouse number,
and geographical location. Provenance records include the
details about the agricultural operations in terms of identity,
date & time, person, digital-signature, location, operation-
type, inputs & memo, and company. The agriculture tracking
platform consisted of three components- data node, clients
and registration center. The issues in the agriculture system
such as creditability of data and integration the subsystems
were easily handled by this open data-sharing platform. Due
to this, any participant could view the data uploaded by any
participating companies, which was also one of the major
advantages of this platform.
According to Tian et al. [192], food safety is the major
concern, especially in China. As China is an agricultural
country, the annual demand for vegetables and fruits is ap-
proximately 730 million tons [199]. Due to the huge demand
of the market, traditional agri-food logistics are not capable
of handling this situation. There are some open challenges
in traditional agri-food logistic systems such as deficiency
of funds and modern equipment, shortfall of a monitorable
traceability system, moderate level of information, and un-
ordered regulatory systems. Therefore, there are massive
and frequent brokedown events of food safety in China.
To overcome the limitations of the traditional agri-food lo-
gistic systems, the authors of [192] proposed a blockchain
and RFID-based agri-food supply chain traceability system.
This system significantly improved the quality and safety of
food, and also reduced the probability of different losses in
the conventional logistics process. The building process of
the system included various stages such as production link,
processing link, warehouse management link, distribution of
cold chain link and sales link. The authors compared and
analyzed the proposed traceability system with the traditional
traceability systems using various parameters. The authors
also discussed the advantages of using the blockchain and
RFID technology in the proposed system. As stated by the
authors, the major advantage was that the traceability sys-
tem totally removed the necessity of the trusted centralized
agencies and provided a data sharing decentralized platform
through which all the users could carry out their respective
operations with openness, neutrality, transparency, security,
and reliability.
Lin et al. [199] developed a blockchain-based traceability
24 VOLUME 4, 2016