SUGISAKAMASANORI

Journal of Robotics, Networking and Artificial Life
Vol. 9(3); December (2022), pp. 240–244
ISSN (Online):2352-6386; ISSN (Print):2405-9021
https://alife-robotics.org/jrnal.html

Research Article

Cross-organizational Non-repudiation Industrial Control Log
System Based on Blockchain
I-Hsien Liu1, Yao-Chu Tsai1, Chu-Fen Li2, Jung-Shian Li1

Department of Electrical Engineering / Institute of Computer and Communication Engineering, National Cheng Kung University, No.1, University Rd.,
East Dist., Tainan City 701401, Taiwan
2
Department of Finance, National Formosa University, No. 64, Wenhua Rd, Huwei Town, Yunlin County 632301, Taiwan
1

ARTICLE INFO
Article History
Received 03 November, 2021
Accepted 11 September 2022
Keywords
ICS security
Data integrity
BlockchainABSTRACT

Industrial control system (ICS) and critical infrastructure have become increasingly dependent on
cyber-physical systems nowadays. Since ICS network is vulnerable to adversarial attacks,
building secure operation mode is essential. In order to secure the integrity of data in ICS, thispaper proposes a blockchain-based log system implemented on physical industrial equipment.
Applying cross-organizational blockchain transaction mechanism in the specialized master-slave
network model, industrial control transmission logs can be verified and non-repudiation© 2022 The Author. Published by Sugisaka Masanori at ALife Robotics Corporation Ltd
This is an open access article distributed under the CC BY-NC 4.0 license(http://creativecommons.org/licenses/by-nc/4.0/)

Log verification

government as well as industry. In 2019, The Departmentof Homeland Security, United States published “A Guide
to a Critical Infrastructure Security and Resilience” toregard CI security as national security [1]. ICS relies onsecure data collection and transmission to avoid damage.
As a subgroup of ICS, Supervisory Control and Data
Acquisition (SCADA) system is composed of hardware
and software to implement data storage, processing, andcommunication. For instance, Programmable logiccontroller (PLC) is one of operating component in
SCADA, which transmits signal among manufacturing
equipment and machines, serving as a fundamental partin cyber-physical system [2].
PLC is basically a terminal device that can online control
low-level I/O devices, such as sensors or motors, andusually connects to the PC via Ethernet to embedprogram. As a kind of embedded system on the Industrial

1. Introduction
With the development of automation and network
communication in modern manufacturing technology,
the concept of Industry 4.0 has been proposed in recentyears, also known as the Fourth Industrial Revolution.
The Industrial Internet of Things (IIoT) is one of thewidely researched issues. The purpose is to innovate in
the industrial economy, construct a smart-conscious
industrial environment, and develop smart factories withadaptability, resource efficiency and human-machinecollaborative engineering.
Critical infrastructure (CI) is related to Industrial Control
System (ICS) which contains various kinds of IIoT.
Security and reliability of ICS has become a concern ofCorresponding author’s E-mail: ihliu@cans.ee.ncku.edu.tw, yctsai@cans.ee.ncku.edu.tw, chufenli@gmail.com, jsli@mail.ncku.edu.tw
www.ncku.edu.tw, www.nfu.edu.tw240changing or upgrading hardware because of cost and thepossibility of production interruptions [4].
Modicon is a brand belonging to Schneider Electric. In
1979, Modicon announced a master-slave architecture toimplement Modbus protocol. This paper refers to thisframework concept and constructs a master-slavemechanism for message verification based on blockchain.
For the purpose of implementing blockchain in ICS
environment, we design a network architecture presentedin Fig. 1. The framework is a master-slave networkmodel imported in ICS [5].

Internet, it is exactly at the risk of encountering network
attacks. In 2021, a real incident happened in a water
treatment plant in Florida. A hacker tried to remotely
hack into the water purification control system with anattempt to fill a potentially harmful chemical [3].
In order to ensure the integrity of data delivery andinformation security, this paper designs a blockchainbased network architecture for operation logs verification
in industrial control system.
2. BackgroundIn this section, we mainly discuss a widely used ICS
protocol and a type of electronic certificate for virtual
assets in blockchain.
2.1. Modbus TCP
Modbus is one of the standard communication protocols
among PLCs, and it is also commonly used in the current
industrial field. Furthermore, Modbus TCP can transmit
data through Ethernet TCP/IP. Because Modbus is aplaintext protocol belonging to the application layer, it iseasy to be interpreted or tampered by hackers, able toconduct man-in-the-middle attack (MitM) and othermalicious behaviors.

Fig. 1 Blockchain-based ICS network model

2.2. Non-Fungible Token

The network model explains the ICS devices, such as
PLCs, industrial equipment, and electric machines, areclients of the proxy server. The proxy server connects toblockchain, so that it can communicate in a protectedenvironment, transferring message to the ICS devices inthe LAN. PC is usually used to be a proxy server, which
is more suitable for fast executing blockchain programsin terms of performance. This paper makes use of theconsensus certificate from a blockchain transaction toguarantee the data integrity when ICS devices transmits
signals. In our architecture, the proxy server executes
blockchain transactions for ICS devices.
We propose a method to wrap the Modbus contexts in a
block when processing blockchain transactions. Block isa JSON file containing some transaction information, andthere is an “extraData” field in it. Putting the message
content of a Modbus packet in this field for the sake oftransmission in blockchain, data sealed in blocks cannot
be easily tampered from logs.
Combined with the immutability property of blockchain,
we set a management server to efficiently protect all

Non-Fungible Token (NFT) is a cryptocurrency based onblockchain that is often used in games and artworks Each
NFT represents specific digital data with a unique codethat can be stored in blockchain. Electronic files that canbe easily copied in the past, such as pictures, audio files,videos, etc. They are difficult to identify whether areoriginal files. Now digital data can be made into NFT
form to get verification via blockchain transaction logs.
3. System Architecture
There is explanation of proposed method and overall
framework in this section. Building a system to generatecredential logs through blockchain transactions, theobjective is to coordinate cross-organizational operations
and leave common operation logs as evidence forauditing.
3.1. Network Model
The requirement on IIoT is strict due to transmission timeand memory space. Most business owners tend to avoid241

Phase 1: Request from domain A to domain B• Step 1: PLC A sends Modbus TCP packets to proxy
server A to request authentication to access theresources of PLC B.
• Step 2: Proxy server A and proxy server Bsynchronizes the account information of each other.
• Step 3: Proxy server A initiates a transaction throughthe blockchain and transfers the Modbus TCP
message to proxy server B in the extraData field.
• Step 4: Proxy server B accepts the transaction andsigns the certificate by its private key.
• Step 5: Proxy server B takes out the Modbus TCP
message in extraData field and sends it to PLC B.

account information on the network and record thetransaction process. With buffer storage, proxy servers
regularly back up operation data read from ICS devices.
And then the management server synchronizes thetransaction logs stored in local proxy servers.
The master-slave architecture also makes blockchain
verification mechanism compatible in ICS environment.
With servers in the blockchain platform, ICS devices do
not need imbedding extra software or changing setup for
blockchain application.
3.2. Blockchain-based Registration Process
According to water resources organization structure inTaiwan, including reservoirs, dams, spillways, weirs, andclean pools, this paper plans blockchain-based
registration and transaction process for crossorganizational operation.
The blockchain-based registration process we propose
consists of three divisions, PLC, proxy server, andmanagement server. The process is as follows.
••
•
•
•
•

Phase 2: Response from B to A
• Step 6: PLC B sends proxy server B a Modbus TCP
packets to make a reply to PLC A.
• Step 7: Proxy server B initiates a transaction throughthe blockchain and transfers the Modbus TCP
message to proxy server A in the extraData field.
• Step 8: Proxy server A accepts the transaction andsigns the certificate by its private key.
• Step 9: Proxy server A takes out the Modbus TCP
message in extraData field and sends it to PLC A.
• Step 10: Proxy server A and proxy server B
synchronize their transaction information to themanagement server for transaction record backup.

Step 1: PLC provides the Device ID to its proxyserver. The objective is to ask for creating a new
account in blockchain.
Step 2: Proxy server sets up an account public key,
and then requests the management server to become
its peer.
Step 3: Proxy server peers with management serverand send the corresponding information tomanagement server.
Step 4: The management server synchronizes theaccount information of the proxy server.
Step 5: The account pointing to the PLC is added in
the blockchain by management server.
Step 6: Management server returns a message toconfirm the proxy server that the registration has
been successful.

4. ExperimentThis paper applies blockchain to record the holding
register status of a PLC using Modbus TCP query via
Ethernet. Experiments are conduct in the blockchain
platform based on Ethereum, generating transaction logs
to be preserved in a standardized format called NFT.
Containing information about ICS operation, these logs
can serve as non-repudiation digital evidence. In addition,
a database is created, providing transaction query toassist evidence investigation work. ICS field operation
data can be collected from the management server system
if it is necessary to clarify responsibilities.
The experimental environment setup is shown in Fig. 2.
During online transactions among proxy servers, the3.3. Blockchain-based Transaction Process
After finishing blockchain registration process,transactions can be launched among accounts. The
blockchain-based transaction process we design mainly
includes five elements, PLC A, proxy server A, PLC B,
proxy server B, and management server. And the wholeprocess can be divided into two phases.

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transaction logs as NFT form are eligible to become nonrepudiation evidence since it is not easily tampered. Our
blockchain server platform complies with thecoordination of ICS devices and IT management system.

Modbus data is transferred with blockchain verification.
At the end of each transaction, proxy servers peer withAcknowledgements
This work was supported by the Ministry of Science andTechnology (MOST) in Taiwan under contract numbers
MOST 110-2218-E-006-013-MBK and MOST 1112218-E-006-010-MBK.
References
1. F. Enayaty-Ahangar, L. A. Albert, and E. DuBois, “A
survey of optimization models and methods forcyberinfrastructure security,” IISE Transactions, vol. 53,
no. 2, pp. 182-198, 2020.
2. A. Ghaleb, S. Zhioua, and A. Almulhem, “On PLC
network security,” International Journal of Critical
Infrastructure Protection, vol. 22, pp. 62-69, 2018.
3. CNN, “Florida water treatment facility hack used adormant remote access software, sheriff says,” [Online].
Available: https://edition.cnn.com/2021/02/10/us/floridawater-poison-cyber/index.html. [Accessed May. 26, 2021].
4. G. Bonney, H. Höfken, B. Paffen, and M. Schuba,“ICS/SCADA Security Analysis of a Beckhoff CX5020
PLC,” 2015 International Conference on Information
Systems Security and Privacy (ICISSP), Feb. 9-11, 2015.
5. C. Wu, J. Lu, W. Li, H. Meng, and Y. Ren, “Master-slave
Blockchain Based Cross-domain Trust Access Mechanism
for UPIOT,” 2020 5th International Conference on
Computer and Communication Systems (ICCCS), May.
15-18, 2020.

Fig. 1 Experiment environment setup

the corresponding management server, synchronizing
their transaction logs. Making the logs into NFT for
private data preservation is also applicable so that
network administrator can examine all operation records.
By adjusting the block generation period in genesis block,transmission time measurement can be implemented withvarious conditions, and the result is shown in Table 1. We
found that the transmission time approximates theproduct of the block generation period and the number ofblock confirmation (B.C.).
Table 1. Transmission time with different periods
Period(sec)B. C.

Number ofTransactions

1351015

3211
11000
1000
1000
1000
1000

AverageTime(sec)
3.00046.00085.001010.001915.0006

Standard
Deviation(sec)
0.05240.07720.05130.0826
0.0561

Authors Introduction
Dr. I-Hsien Liu

He is a research fellow in the Taiwan
Information Security Center @National Cheng Kung University(TWISC@NCKU) and Department
of Electrical Engineering, National
Cheng Kung University, Taiwan. He
obtained his PhD in 2015 in
ComputerandCommunication
Engineering from the National Cheng
Kung University. His interests are Cyber Security,
Wireless Network, Group Communication and Reliable
Transmission.

5. Conclusion
ICS cyber security has been a research focus nowadays.
For the purpose of ensuring the transmission integrity,
this paper applies blockchain verification to industrialnetwork. The designed master-slave network model
would improve the adaptability of blockchain mechanism
in ICS. We also plan the registration and transaction
process in cross-organizational framework, conducting
implementation on physical industrial equipment. The243

Mr. Yao-Chu Tsai

He was born in Pingtung, Taiwan in
1997. He received his B.S. degreefrom the Department of Systems andNaval Mechatronic Engineering,National Cheng Kung University,Taiwan in 2020. He is acquiring themaster’s degree in Department ofElectrical Engineering / Institute ofComputer and Communication
Engineering, National Cheng Kung University in Taiwan.
Prof. Chu-Fen Li

She is an associate professor in theDepartment of Finance at theNational
Formosa
University,
Taiwan. She received her PhD in
information management, financeand banking from the EuropaUniversität Viadrina Frankfurt,
Germany. Her current researchinterests include intelligence finance,
e-commerce security, financialtechnology, IoT security management, as well as financial
institutions and markets. Her papers have been publishedin several international refereed journals such as European
Journal of Operational Research, Journal of System andSoftware, International Journal of Information andManagement Sciences, Asia Journal of Management andHumanity Sciences, and others.
Dr. Jung-Shian Li

He is a full Professor in theDepartmentofElectricalEngineering, National Cheng Kung
University, Taiwan. He graduatedfromtheNational
TaiwanUniversity, Taiwan, with B.S. in
1990 and M.S. degrees in 1992 inElectrical Engineering. He obtained
his PhD in 1999 in Computer Sciencefrom the Technical University of Berlin, Germany. Heteaches communication courses and his research interests
include wired and wireless network protocol design,network security, and network management. He iscurrently involved in funded research projects dealing with
optical network, VANET, Cloud security and resource
allocation, and IP QoS architectures. He is the director ofTaiwan Information Security Center @ National Cheng
Kung University. He serves on the editorial boards of theInternational Journal of Communication Systems.

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