The smart grid idea was implemented as a modern interpretation of the traditional power grid to find out the most efficient way to combine renewable energy and storage technologies. Throughout this way, big data and the Internet always provide a revolutionary solution for ensuring that electrical energy linked intelligent grid, also known as the energy Internet. The blockchain has some significant features, making it an applicable technology for smart grid standards to solve the security issues and trust challenges. This study will present a rigorous review of blockchain implementations with the cyber security perception and energy data protections in smart grids. As a result, we describe the major security issues of smart grid scenarios that big data and blockchain can solve. Then, we identify a variety of recent blockchain-based research works published in various literature and discuss security concerns on smart grid systems. We also discuss numerous similar practical designs, experiments, and items that have recently been developed. Finally, we go through some of the most important research problems and possible directions for using blockchain to address smart grid security concerns.

1. Introduction

Internet of Things (IoT) is considered the most uncontrollable innovation in today’s world; this improves our ordinary life by reworking the bodily items that surround us into an ecosystem of facts. IoT and big data have numerous applications in day-to-day life, i.e., security, transportation, industrial, retail, healthcare, home automation, military, agriculture, surveillance, and good infrastructure. Indeed, IoT and big data have heavily driven nowadays smart grid developments, and smart meters are progressing by featuring more vital sensing abilities and higher connectivity [1, 2]. The smart electricity generation, transmission, and distribution system and smart buildings/homes are all controlled and explicitly maintained by ICT devices like WAMS, IEDS, and RTUs for service systems, as well as AMIs for smart building/home management in the smart grid (SG) [3]. The IoT-enabled field measurement data can be safely and automatically collected by including the blockchain control and field measurement with smart communication to these ICT devices in HAN/SN, NAN, and WAN [4]. Furthermore, blockchain-enabled AMIs can use DAPPS services to conduct decentralized system capacity, local power management, and trading in a cyber-secured environment [5].

The days are passing. Civilization is also progressing rapidly. Science is becoming more powerful as time passes. Simultaneously with the problems that the modern world presents, scientists and engineers face difficulties in satisfying market demand at various levels for various reasons. The total electricity generation, transmission, and distribution system are becoming a loss project because of a lack of raw electricity generation raw material supply, corruption on both the transmitting and receiving ends, transmission line and distribution system losses, and other factors. As a result, the SG technology was developed to meet consumer demand, improve the electricity generation and distribution system efficiency, ensure customer protection, and monitor and regulate the entire system through communication (generating and receiving end). As a result, the critical focus of the paper is to include an overview of blockchain (BC) in smart grid and energy trading presented in Figure 1.

Beyond the area of computer vision, this article will contribute as a supplement to an adversarial attacks’ summary and protections for SG IoT and big data linked devices and networks. The contribution of this study is discussed below. (1)General Working Flow. We review an overall working flow to describe the Internet-connected devices, protocols, and network infrastructure and its adversarial attacks in SG big data/IoT networks. The integration of the potential BC technology in SG IoT networks is presented. Based on this, a robust classification is provided to organize and structure existing attacks intricately and effectively where the defenses can be possibly accomplished in SG IoT-connected devices and networks.(2)Systematic and Comparable Studies. We classify current attacks based on the above taxonomy into three standard sensor data types: textual, audio, and surveillance sensor data. Here, we also did a quantitative comparison between them based on six technical factors. In addition, we define as well as outline three possible defense strategies for aggressive attacks in CPSs.(3)Open Issues and Opportunities. We highlight several existing research prospects which should be pursued in the future in order to inspire and enhance future follow-up on this research topic.

The overview of this paper’s structure is presented in Figure 2. Section 2 discusses the study methodology and the relevant research on IoT security specifications. Section 3 examines the findings, highlighting critical characteristics for understanding IoT and general security criteria related to the entire lot system. Section 4 presents the overview of blockchain technology and its application. Finally, in Section 5, we present the findings of this study, and the conclusion is in Section 6.

2. Research Methodology

2.1. Research Questions

Research questions. The following research questions are to be analyzed and accomplished throughout the paper: (1)What are the recent features technologies in SG?(2)What are the security vulnerabilities, threats, and their counter measurement in SG?(3)What are the blockchain technology and the security mechanism that attracted the researchers to security solutions for SG?(4)What are the critical success factors of the blockchain that can ensure the security of SG systems (smart metering, energy trading, SG communication systems, etc.)?(5)What are the issues and challenges of the blockchain- (BC-) based security solutions, and what are the possible enhancements of the blockchain framework that strengthen the security in SG?

2.2. Review Protocol

The specific review protocol of the procedures can be followed during the studies. It is necessary to make assessments almost the review issue, data extractions, data synthesis, inclusion criteria, quality assessment, search strategy, research collection, and dissemination plans. Only full published conferences and journals in the English from 2010 and 2021 were considered. Data sources, data extraction, research collection, and selection strategy process are the main components of the review protocol.

2.3. Data Sources

To assist in answering the research questions, research papers related to blockchain, IoT, and big data were chosen. Related research articles which are not addressed or even endorse with the research questions were rejected. Our primary resources for looking the published research publications are in the following libraries: (i)Science Direct(ii)IEEE Xplore Digital Library(iii)MDPI(iv)Taylor and Francis(v)Springer Link(vi)ACM Digital Library(vii)Google Scholar

2.4. Search Process

Based on the research methodology, we focused on IoT and blockchain-based keyword patterns to find any research queries. We apply Boolean operators and symbols like “AND,” “OR” to find out the following keywords: (block chain OR (block chain technology) OR (block chain security AND block chain issues) OR (IoT security)) OR (big data in SG) AND (study OR Adoption) AND ((requirements AND solution) OR (benchmark AND regulation)) AND ((block chain application AND fields). Figure 3 presents this process.

2.5. Data Selection

The data collection is the deciding process of the appropriate data source and type and perfect implements to collect the data. Data selection precedes the actual repetition of data collection. Data selection criteria were as follows: (i)Has been the study paper written between 2010 and July 2021?(ii)Is the research paper published in the well-known/referred data sources?(iii)Does the research paper reference or address BC/IoT/big data?(iv)Is there any discussion of security, requirements, or practice in the research paper?

2.6. Data Extraction

In July 2021, we completed the search process and discovered 269 publications and websites. Related research papers were carefully extracted by following the collection and rejection criteria as part of the search process. Finally, preliminary results were found from 142 abstract studies and 57 full-length reviews and research work for studies. The data synthesis and extraction of the selected review papers to find the research question answers and classify the studies shown in Tables 1 and 2 present the IoT and blockchain application field, respectively.

3. Smart Grid System and Security Analysis

The term “SG” states to a concept that encapsulates the entire electricity generation, transmission, and distribution system in a single edging. In other words, an SG makes smarter the entire system more competent or safer. Clean energy is now in high demand all over the world. As a result, clean energy is also called smart energy. The word “smart grid” was first used in the year 2003 [6]. That was the first time Michael T. Burr used the word in a document. He clarified how the power grid’s flaws could be detected and fixed to improve the power flow mechanism from generation to delivery across the whole transmission lines. This SG idea is now a reality, and the SG design objectives are presented in Figure 4. It was becoming a fact through the excellence of executing some one-of-a-kind function that makes things simpler. The SG is prepared smart by exhausting the national grid’s security mechanism and central control via the supervisory control and data acquisition (SCADA), transmission equipment monitoring and diagnostic, grid computing, handling the whole power system as a hybrid adaptive power system, and using distributed computer agents to make the self-healing power system network [7].

3.1. Smart Grid Systems

The development of a highly secure, dependable, and eco-friendly national power grid system, termed the SG, is being driven by rising concerns about greenhouse gas emissions like carbon dioxide (CO2) and the demand for additional efficient and dependable power transmission and distribution [8]. An SG uses two-way digital technology to transmit power between providers and consumers. It monitors and regulates smart appliances in users’ homes or buildings to conserve energy, save costs, and improve dependability, efficiency, and transparency (Figure 5) [9]. The legacy power network is intended to be modernized by a smart grid. It automatically monitors, protects, and optimizes the function of the associated pieces. Several of the SG technologies are already in use in different industrial regions, like manufacturing process of wireless and sensor networks in telecommunications, and are starting to be modified for application in the different intelligent fields and linked scenarios such as energy distributions, communication systems, energy metering, and energy trading. The conventional power delivery system focuses on designing technology that improves the power supply’s integrity, availability, and secrecy. Until recently, modern communication technology and equipment were thought to be boosting the dependability of the power industry. Nonetheless, the growing connection is becoming more critical for the power system’s cyber security. In particular, securing the electrical grid system protects, arranges for, recovers, responds, and mitigates from unexpected cyber system incidents or natural catastrophes [10].

The integration of security system/protocol/algorithm with smart grid (SG) technology is becoming so sophisticated key solutions for facilitating comprehensive security functionality SG technology. The core related interfaces, components, and applications of SG that are critically security dependent are discussed in analyzing the key RQs. The feature of SG is presented in Figure 6.

3.1.1. Smart Meters for Energy Trading

Smart meters (SMs) are distinctive characteristics of SG technology that become a most reliable device for data measurement in electricity generation, transmission, and consumption. The SMs combine use with digital meters and communication systems to allow real-time monitoring of the consumers’ energy [2]. In simple terms, a SM is a meter that calculates the amount of electricity used by customers. It usually records the reading at several times during the day. A typical SM assists the customers to understand electricity consumption and billing procedures; therefore, they can easily manage their usage electricity inside their desired budget/billing limit.

On the other hand, the SM measurement aids the suppliers and consumers in calculating accurate bills for customers. SM acts as a contact point between households and the Distribution System Operator (DSO), part of energy transactions. It is crucial to have a secure connection between SM and utility servers because it can affect transactions and billing information. It is essential to maintain track of the transactions in terms of planning the operation and compute invoices. When several parties engage in any kind of trading, trust is a big challenge. Initially, the record of transactions is maintained by a responsible third party. For SM-DSO transactions, blockchain technology can be used to maintain a distributed ledger. As a result, they were implementing blockchain technology to trade energy required to be trusted on their third party [1115].

3.1.2. Distributed Generations

Smart grid technology relies heavily on distributed generation (DG). The term “distributed generation” refers to the production of electricity from various small energy sources. Massive power plant generation has inevitable consequences, such as environmental effects on transmission and distribution and a very stable electricity supply via the grid [6]. The present electricity networks are becoming more overburdened as demand rises regularly. As a result, traditional strategies contribute to the complexity of existing networks. To meet customer expectations on the distribution side, such as lower power bills, increased comfort, reliability, and data security, a comprehensive analysis of SG components such as distributed generation is necessary [9, 16]. Integrated minor nonconventional power resources can be utilized to produce electricity at the load end in distributed generation. This technology improves power quality, efficiency, reliability, and security while lowering operational costs and environmental impact [10, 17].

3.1.3. Integration of the Renewable Energy

The interconnection of renewable energy is another critical function of the SG system. Improving the grid’s IRE (Integration Renewable Energy) capability allows the national power grid to address customers’ increased demand while maintaining future security. Like the DG (distributed generation), IRE will face some difficulties as it integrates into the smart grid.

3.1.4. Two-Way Communication System

The SG system is more straightforward for both suppliers and consumers when the bidirectional communication system is activated. The SG communicates in two-way communication with consumer’s alert of the price and energy consumption as well as electricity generation, and suppliers are aware of the simple billing system of usage electricity. Cyberphysical security employs communication interfaces such as Universal Asynchronous Receiver-Transmitter (UART), Ethernet, and WLAN for the complex Internet Connected SACADA and PMU device WAMS in SG networks. The IEEE C37.118, Gateway Exchange Protocol (GEP), SIEGate has been designed and presented to secure cyberphysical communication interface, gateway, and control systems. Furthermore, only this communication device allows for central control of the entire grid. However, one thing to keep in mind is that privacy must be protected when interacting in the SG system, whether multidirectional or bidirectional.

3.1.5. Automatic Healing Capability

Since SG system is a cognitive approach for electricity generating and distributing with a high level of data protection, convenience, and robustness, the SG must provide one feature: Automatic Healing Capability (AHC). This function comprises automatic identification of unstable system conditions, such as overcurrent, fault current and surge voltage, and information transmission from the central control room and fault or disruption healing/recovery capability.

3.1.6. Carbon Emission Reduction

The SG is called Green Grid. Since it can integrate renewable energy sources into the grid and efficient energy production and distribution, SG technology can help reduce carbon emissions by a significant amount.

3.1.7. Meter Data Management

The key component of Advanced Metering Infrastructure (AMI) is data management systems of the meter [18]. Meter data management (MDM) is a software that stores and manages enormous amounts of generated data by SM systems over time.

3.1.8. Field Area Networks

In power delivery, field networks help build impregnable connectivity between various field equipment, such as transformers, distributors, and smart electronic devices. Near field instruments, several electrical sensors are mounted [19].

3.1.9. Electricity Storage Devices

Energy storage systems in many mobile devices have found excellent applications. Therefore, the environmentally safe products replace the standard battery-acid metal storage equipment, requiring more charging time and less acid use. Based on the SG feature and application, Table 3 presents the contribution of some published work.

3.2. Attack in Smart Grid

Scanning, surveillance, maintaining, and manipulation are the major four access and measures to use by hackers to target the devices and gain access and control [12]. The attacker collected and gathered information to their target through the first phase, reconnaissance. In the second stage, they take attempts to locate the system’s vulnerabilities. These movements are designed to learn and identify the service methods on the open port operating system individually and their flaws. They make an attempt to gain and concession the complete control system during the goal exploitation period. When the target administration access is gained, then the final move must be complete and continuously can access. This is consummate by installing an undetectable and stealthy program, consenting them to simply back to the target system. In SG, security criteria are a concession with attackers [1] following the same steps. They apply various methods to compromise a specific system in the SG at each level. As a result, these steps can be used to classify attacks. The types of attacks that occur during each stage are presented in Figure 7. It depicts the variety of attacks that could occur during the exploitation process. The attacks and the malicious activities have occurred during every step.

3.2.1. Reconnaissance

Attacks such as traffic analysis and social engineering are part of the reconnaissance process. Instead of technological skills, emphasize human interaction and social skills in social engineering (SE). An attacker applies persuasion and communication gain to legitimate the user’s confidence to obtain private and credential information, i.e., PIN or passwords to log in to the server. For instance, password and phishing attacks have become well-known methods used in SE [41]. The traffic analysis listens to the attack and analyzes network traffic to decide which computers and hosts connect to the network and their IP addresses. The security of information is primarily jeopardized by social engineering and traffic analysis.

3.2.2. Scanning

The scanning attack is the next move in discovering all of the computers and hosts on the network that are still alive. Scans can be divided into four categories: IP addresses, ports, utilities, and security flaws, which are all things that need to be considered [42]. An intruder usually begins to identify the network with an IP scan in the hosts connected with their won IP addresses. Then, they explore a little deeper by port, checking to see which ones are available. This scan process is run on any host network that has been discovered. After that, the attacker performs a service scan to determine which service or device is running behind each opened port [41]. The final stage is vulnerability scanning to find the flaws, aims, and vulnerabilities associated with every service system on the target devices to be exploited later. Industrial protocols Modbus and DNP3 are also susceptible to scan attacks. The TCP/Modbus was developed to protect the communication system rather than hack by using the scanning Modbus network technique. Attacker entails sending a harmless message to all network-connected computers to collect their information. Mods scan is a well-known scanner on the SCADA Modbus network that can detect and open TCP/Modbus connections and identify system IP addresses and slave IDs.

3.2.3. Exploitation

The SG system components are exploited by malicious activities and attempt to gain control and vulnerabilities over it are included in the third phase, exploitation [41, 43]. Viruses, worms, and Trojan horses popping the human-machine interface (HMI), privacy violations, channel jamming, and integrity breaches, as well as different attacks like denial of service (DOS), man-in-the-middle (MITM), and replay attacks, are all examples of these activities [24]. In the SG, viruses are a program that infects a particular computer or machine. A worm is a program that replicates itself. It spreads across the network, copies itself, and infects the system and other devices. A Trojan horse is a computer program that pretends to do something useful on the target machine. In the context, however, it executes malicious code. An attacker uses this form of malware to infect a computer with a virus or worm.

3.2.4. Maintaining Access

In the final stage, the attacker applies a specific attack form for retaining access, such as backdoors, viruses, and Trojan horses, to obtain permanent access to the target. An undetectable program like a backdoor is mounted for the target invisibly to be quickly and easily accessed. Suppose the attacker is successful in surrounding a backdoor into the SCADA server control. In that case, they will be able to initiate a series of attacks in contradiction of the system, which will significantly affect the power system [41]. The security criteria on the IT network is defined in the following order based on their importance: confidentiality, honesty, transparency, and availability. They are known as availability, honesty, transparency, and confidentiality in the SG. As a result, attacks that compromise the availability of smart grid networks are considered to be of high severity.

In contrast, attacks that target confidentiality are considered to be of low severity. Every attack has a degree of probability of being carried out in addition to its intensity. Attacks like Stuxnet and Duqu, for example, have a high intensity because they can vandalize industrial control systems and circumvent all security barriers; however, they are complex and complicated [44]. As a result, these viruses are hazardous, but their chances of being spread are poor. The popping HMI attack is another example. It is a highly severe attack requiring specialized networking expertise or extensive experience with industrial and security control systems. While the vulnerability documentation for the devices is publicly accessible, a hacker may quickly launch an attack using open source tools, including Meterpreter and Metasploit. As a result, this attack has a high probability of being carried out.

3.2.5. Impact of the Cyber Attack

Significant impacts can cause cyber attack (CA) on economic and physical/technical impact in SG. Though recent research has concentrated on cyber technical/physical attacks on SG, it is also essential to focus more on CA economic risk. The SG has faced a significant economic problem for CA [45, 46], specifically renewable energy resources with high penetration grid-connection mode. The electricity market is a combination of real-time and day-ahead markets [47, 48]. Mainly, the day-ahead market focused on solving the optimization and load forecasting problem at a minimum cost. The optimization problem explains the location marginal price (LMP) of electricity in different locations at each bus (economic dispatch) since load forecasting is affected by false data injection (FDI) CAs in the day-ahead market.

In contrast, the real-time market estimates the generated power and load power for each bus/line. Each line power is required to calculate to achieve the congestion pattern (when estimated line power exceeds the maximum power limit congested), and real-time LMP can estimate this. Thus, FDI state estimation on CA significantly impacts the real-time market that is briefly discussed in [4651].

The FDI attacks have significant technical/physical impacts on SG. Typically, SG faces steady-state stability and transient impact for FDI attacks. The FDI attacks on steady-state stability significantly impact SG voltage control (AC/DC voltage control in AC-DC SG), demand current/voltage/power management, and energy management [5256]. Additionally, the CA has an adverse effect on SG steady-state operation; the FDI attacks have impacted SG dynamic and transient stability. Currently, the SG frequency control system can be affected by FDI, but rotor angle stability will be the target [52, 5761]. Moreover, all of the attacks were occurred in SG protection system.

3.2.6. Cyber Security

SG infrastructure must be protected against a variety of threats and attacks. Hackers, attackers, organized crimes and cyber terrorists, certain criminal elements, poorly or careless workers, and industrial rivals may all attack the SG. To abuse the vulnerability system, individual criminals, a group of hackers, attackers, organized criminals, and cyber terrorists may target SG systems and networks. Poorly qualified workers running the system carelessly will create the entire system susceptible to physical/cyber security attacks. Since infrastructure is interrelated across the system, if one part of the SG cyber security (CS) network is targeted, the whole system is at risk, resulting in a complete blackout or system failure. As a result, CS must be robust sufficient to ensure the system’s smooth and effective operation. Data privacy, secrecy, and verification are essential for the infrastructure’s security and performance of SG applications. Disregarded cyber security strategies must be implemented to protect data security and supervise the infrastructure to prevent unwanted alterations across the infrastructure [41, 62]. There are several security flaws in SG applications, and each has its unique features. SG applications are vulnerable to diversity of cyber threats that might harm the moderate to more comprehensive level [24, 63]. A jamming attack can only be carried out by accessing the data transmission channel. Stuxnet and other zero-day attacks pose the risk of undiscovered data breaches within control systems. These data breaches may only be identified after the attack is executed [42, 64].

The attacker interrogates the communications between the nodes on the data transmission in an eavesdropping attack [20, 65]. Privacy can be compromised by password theft, traffic analysis on MITM, spoofing attacks, and overhearing. Reliability might be affected by data injection, wormhole data injection, task scheduling, spoofing attacks, and data manipulation. DoS, puppet, buffer overrun, wormhole, jammer, and flooding attacks cause security breaches [20, 65]. Services, applications, end nodes, and networks are the four levels of IoT-based information security solutions for smart infrastructures. Cyber attack (CA) countermeasures include intrusion detection systems (IDSs), sensor verification, compact cryptography, causal inference, and antijamming at the application level. Authorization, anti-DoS, pattern detection, intrusion prevention, cryptography, load balancing [47], ant jamming, and packet filtering are all elements of CA remedies at the network layer. Access control, encryption, pattern detection, authentication, information manipulation, controlled disclosures, and session identifiers are all components of cyber attack solutions at the service layer. CA solutions comprise verification, encrypting, and analysis of the anomaly behavior of software and systems at the end-node layer [43, 66]. Figure 8 shows the security solutions for IoT-based information security applications.

3.3. Security Requirements in Smart Grid

CS is a crucial concern due to the risk of CAs and accidents beside this critical industry as it associated with interconnected, according to the EPRI report. Not just malicious threats by malicious workers, corporate espionage, and hackers, but even accidental breaches to the communication system due to software errors, computer faults, and natural disasters must be addressed. Vulnerabilities may enable the attacker to break into a network system, manipulate load conditions and control the gain access in the software to disrupt the power grid in unexpected ways. In the SG system, there are two kinds of data that are shared. Specifically, data and functional data [67]. The logging system, energy trending, power billing, marking, geographical areas’ historical reporting, customers’ records, and emails are all examples of information. Real-time voltage and current values, capacitor banks, load current, transformer feeder, transformer tap changers, relay position, circuit breakers, and fault positions status are examples of operational information. To secure smart grid networks against any weakness or attack resulting in a power outage, operational data demands a high degree of protection. The smart grid’s security criteria and goals are as follows:

3.3.1. Availability

The term “availability” discusses the right to use the information and obtain appropriately and accurately. If the SG's contact information is dislocated, that leads to a loss of availability, so the maximum security criteria are necessary [68, 69]. For example, a lack of availability will disrupt the control system’s functioning by preventing network information, and operator systems prevent the network’s availability. Availability attacks potentially distort, restrict, or hinder data transmission [11, 70]. Additionally, availability attacks in the smart grid prohibit and may disrupt authorized access. It was challenging to target asset availability in the large-scale conventional power grid. ICT is embedded into the power grid’s information assets in the smart grid, allowing them to be attacked and completely inaccessible [12, 71].

The DoS attacks are called availability attacks [13, 72]. DoS attacks attempt to interrupt data transmission by obstructing, corrupting, or stalling it. This makes network sources inaccessible. Availability attacks are designed using several methods to overburden networks to ensure that the system does not operate correctly [14, 73]. Attackers transmit significant volumes of traffic to overwhelm the network’s transmission connections. For this, the valid data package’s presence is lost and not processed in network traffic. IEC 61850 and IP/TCP are IP-based protocol system, which are subject to availability attacks [15, 74]. The most important security prerequisite in SG technology, robust, and comprehensive remedies against availability attacks must be executed. Some successful methods include traffic filtering, big pipes, air-gapped networks, and anomaly detection methods [16, 75]. In SG system, attacks by DoS pose the biggest threat to big data; integrating software solutions in different network layers may prevent DoS attacks significantly.

3.3.2. Integrity

In the SG, integrity states securing data against unauthorized modification or degradation. The absence of integrity ensues when data is destroyed, modified, or altered deprived of existence identified [43]. For example, power injection is a destructive attack by an opponent who intelligently modifies calculations and state estimator from the power flow and injection meters. To protect the dignity, material authenticity or nonrepudiation is necessary. Integrity threats are not limited to unauthorized data alteration or injection. Integrity attacks include device impersonation, sparse, and replay attacks. Data integrity threats are prevented via cryptography techniques and approaches [17, 76]. SQL injection and MITM attacks use gaps in the SG to alter, takeover, or corrupt authorized operations.

In SG application system, the data concentrators are linked to SM HAN’s. On the other hand, an attacker can use unauthorized data alteration or MITM to impair data transmission among the SM and the data concentrator unit. One of the subdivisions of integrity attacks is load-drop attacks [18, 77]. MITM attacks threaten the systems, and CIA’s tried accountability. Security gateways enable the authentication of both target nodes and sources and the confidentiality of data transfer [62, 78]. TLS protocols also include inbuilt asymmetric cryptographic features that can uncover and resolve vulnerabilities efficiently, preventing MITM attacks [63, 75]. By inserting script commands into databases, SQL injection attacks attempt to manipulate databases. SQL injection attacks insert fraudulent demands into the database system to maintain the control system, erase or alter current information, and insert falsified data. SQL injection attacks in the SG network system can be mitigated by using techniques like input type checking, matching the positive pattern, verified static code, database access prevention for remote users, dynamic SQL prevention, and conducting vulnerability scanning. Attackers may use characters such as semicolons; therefore, these characters should be monitored and excluded during type verification [63, 75]. Other kinds of integrity attacks include tampering SCADA systems [64, 79], replay attacks [65, 80], and time synchronization attacks (TSA) [66, 81]. To prevent the mentioned integrity attacks on the SG networks, authentication methods and end-to-end encryption recommendations were used. To launch a confidentiality or integrity attack, attackers can be verified the communication network access and confidential data [19, 24]. As a result, authentication and access control are key to reduce integrity attacks on the SG system.

3.3.3. Confidentiality

In particular, confidentiality protects permitted limits on access to and dissemination of records. In other words, the confidentiality criterion includes preventing unauthorized persons, organizations, or systems from disclosing or accessing proprietary or sensitive details [82]. Confidentiality is compromised if materials are released deprived of permission. For instance, information transmitted among the customer and multiple agencies, i.e., metering use, meter management, and billing information, can be private and protective; else, the customer’s information can be exploited and changed, or other uses nefarious purposes [24]. Confidentiality attacks have a negative impact on the communication network’s functionality. Confidentiality attacks seek toward obtaining the data that should be kept or disclosed confidential between trusted parties. Accessing device memory unlawfully, replay attacks, spoofing payload, and altering the software control of SG are some instances of confidentiality attacks. Password attacks commonly include the social manipulation, dictionary attacks, password sniffing, and password guessing. Social manipulation is a technique of breaking into a scheme utilizing social skills relatively technical skills [15, 74].

Eavesdropping is a kind of passive attack that also compromises data confidentiality [20, 65]. Eavesdropping attacks on local area networks (LANs) in SG networking systems sniff IP packets or intercept wireless transmissions, causing harm to the system’s accountability and transparency. Encryption protects sensitive information from eavesdropping attacks [83]. Traffic analysis attacks are passive confidentiality attacks. Interpreting and sniffing the messages permit the attackers to get crucial data around the communication pattern among the networks. Masquerading attacks, also known as impersonating or identity spoofing, are other confidentiality attacks [84]. Other confidentiality attacks include unauthorized access, MITM, and data injection attacks [10, 63, 78, 84, 85]. To prevent confidentiality attacks, smart grid equipment must include authentication, data encryption, and awareness of privacy protocols.

3.3.4. Authentication

Machine and human authentication is of high importance; besides this, it is also a weakness because it can lead and cause the attacker to gain access to personal and confidential information or illegitimate devices creating procedure of the SG resources [29]. One of the most challenging aspects of SG communication is authentication. The SCADA systems with communication standards and protocol systems are used in modern SG applications. However, these networks’ protocols are often sensitive to MITM attacks, impersonation attacks, and replay attacks. Also, cryptographic keys are applied in the system’s different devices that can be exploited. Integrating the SCADA system into Internet communication infrastructure raises security and privacy risks considerably [86]. Mutual authentication between smart devices can be achieved using identity-based authentication and critical public infrastructure (PKI) methods [87]. To avoid authentication attacks, the late-launch dynamic root of trust for measurement (DRTM) technology can be applied to secure the cryptographic key of a specific device [88]. Moreover, to prevent authentication attacks on a mobile RFID-based SG network, an authentication technique can be developed; however, it adds cost and memory [89].

3.3.5. Authorization

They are granting access and permission to the computer (also known as access control). Because of the large number of devices besides these people involved in a SG network system, an authorization system is needed to ensure that information and resources are adequately controlled [29]. Unauthorized individuals or systems are prohibited from access to the system without authorization [79]. For this CS, required authorization refers to a decision differentiating between authorized and illegitimate parties based on authentication. If authorization is breached, it may result in security risks. Access control ensures that resources in the smart grid are only accessible by appropriate personnel and entities who have been properly identified [80]. Strict authentication measures should be established to prevent unwanted access to sensitive data and vital assets [24]. Flexible access control, compulsory access control, and role-based access control are examples of authentication techniques that can improve system performance and minimize security risks. As a result, access controls are required to limit the device’s network and user’s access.

3.3.6. Nonrepudiation

Attempt to convince that a device or user’s operation cannot be reversed later. For example, an IoT system cannot deny sending a message it has already received. When sensitive resources and knowledge are involved, nonrepudiation becomes a major problem [82, 90]. Data integrity relies heavily on nonrepudiation and legitimacy. Accountability attacks are aimed at changing client information such as account information, payment information, or network operation data such as device status and voltage measurements. Such attacks try to interfere with the source information in the communication network process to interrupt vital communication process in the smart grid [91].

3.4. Security Standard and Protocol

There are many security algorithms, standards, and protocols presented to provide the security in the SG system. In an overall standard, generation companies and customers/consumers are linked in distributed ledger and peer-to-peer communication with a trusted third party (TTP) [92]. In SG application, the widely applicable protocol is open smart grid protocol (OSGP) via encryption techniques. However, the rigorous study shows that OSGP encryption mechanism has some weaknesses. The weakness is generating and transmitting messages by stream cypher encryption with a new key to another customer where only difference is the first 8 bytes of the key. Another issue is using this generate encryption key to use in authentications. After that, when the BC was introduced and used in the SG application, the security issues are solved. Using the existing security protocol in BC architecture became more secure [93]. The existing SG standards and protocols are as follows: AMI-SER [94], CEN-CENELEC-ETSI SG Coordination Group [95], IEC 62351 [96, 97], NERC-CIP [98], IST [99, 100], ISO/IEC 27001 and 27002 [101, 102], GB/T 22239 [103], ISO/IEC 15408 and 18045 [104], IEC Strategic Group 3 SG [105], IEC 62443 (ISA99) [106], IEC 62443 (ISA99) [107], IEEE Std 2030-2011 [108], IEEE 1686 [105], DHS catalog [109], German Standardization Roadmap E-Energy/SG [108, 110], NIST SP 800-82 [99], NRC RG 5.71 [107], NIST SP 800-53 & 800-64 [110], NIST SP 800-115 [108], Open SG Security Working Group [108], ITU-T SG Focus Group [107], SG Interoperability Panel [108, 109], The State Grid Corporation of China (SGCC) Framework [111], European Commission SG Mandate Standardization M/490 [112], and Japanese Industrial Standards Committee (JISC) Roadmap to International Standardization for SG [107].

The SG standard and protocol summary is presented in Table 4, which presents the applicable scope, types, ranges, applicability, communication technologies (CT), and publication year (Pby).

4. Overview of Blockchain (BC)

The BC is a computer network-based archives (big data system), where hackers can access any place worldwide. This is a fully transparent system, where if provisioned for public BC, all service providers and consumers can see the change made and transactions [113]. For this, BC focused on responsiveness in many industries. This is significantly applied in the energy industry, communication, data exchanges, e-treading, and authorization and authentication tamper-proof mechanism. In the point of energy trading, BC technology adopts the grid energy [114].

The block transection of BC is achieved by secure and integrated consensus algorithms [115]. In 2008, the first cryptocurrency, Bitcoin, was introduced in the market and this is the peer-to-peer electronic currency transfer process. In this transection process, without authorization from one party to another party, currency was securely done online transaction by a trusted third party and was first applied in BC technology. This BC technology is significantly and successfully applied in the financial industry, SG, electric vehicle (EV) system, healthcare, IoT, supply chain, etc. [116].

4.1. Blockchain Mechanism for Smart Grid

The integration of BC with SG technology is becoming so sophisticated key solutions for facilitating comprehensive security functionality SG technology. The core related interfaces, components, and applications of SG that are critically security dependent are discussed in analyzing the key RQs. The existing centralized ledger system may be transferred by BC technology into a distributed ledger because of the public key algorithm. It also has end-to-end encryption technology and, due to the distribution processing structure, guarantees low costs. The idea of blockchains is generating a lot of research and functional attention right now. A BC is a cryptographic collection of node blocks, where the headers, corresponding transaction data, and auxiliary protection metadata are secured for each block. Intrinsically, the BC supports free connectivity, incorruptibility, openness and secure storage, and transfer of data [117, 118]. In recent years, several BC implementations have arisen beyond initial cryptocurrency applications, like Bitcoins.

Bitcoin’s BC system is a public data database that saves the history of Bitcoin value transfers updated regularly. To avoid forgery, this ledger is created using cryptographic technology. The BC technology could help solve a numerous complex matters relating to the transparency and trustworthiness of fast, distributed, and complex data exchanges and energy transactions. Smart contracts built on the BC often exclude the need to negotiate with third parties, constructing it easier toward monetizing distributed and implementing energy transfers and connections, containing both energy flows and financial transactions (Figure 9). Table 5 presents some BC-based SG applicable methods and findings.

4.2. Blockchain Mechanism for Energy Trading

In BC technology, energy trading is necessary for academic research and industrial application with emergency SG electricity generation and distribution. The BC technology is used to reduce the fraudulent act. A certificate is issued for achieving the generators/consumers’ trust/guarantee in this energy trading. Implementing BC technology makes the energy trading system easy and helps to reduce the marketing effort and minimize the time. Conventional fossil fuels are diminishing rapidly, and researchers and governments worldwide are looking for suitable alternative energy sources like renewable energy. For this, many smaller generated companies produce energy for smaller grid scale and need to connect in the national grid so that consumers can buy [145, 146].

Additionally, the consumer also produces the energy and sells it on the market. The BC system gives an efficient peer-to-peer trading process for local consumers, which generates a small amount of energy. The peer-to-peer topology automatically handles this data and stores it on the public ledger, where all copies are reflected over the network. The BC technology transmits the data and communicates with SG network in a block node. All nodes are connected where every device shares the address and information with previous devices [115].

4.3. Blockchain Mechanism for Electric Vehicles

Last few years, EV connection with SGs has been an important and hot topic. Primarily, EV charging systems make more concern to connect with the SG. The power grid system can face severe stress for EV irrelevant charging. Thus, BC technology adopted this problem with several approaches. The BC technology in EV charging integration was discussed in [147149]. Researchers recommended integrating the EV charging system with the BC technology to be able to find out a near charging station so that EVs can charge. Using this BC technology, EV was used easily to find out the low cost and best location for EV charging station to ensure the privacy and security system.

5. Discussion

Since smart grid technology is the most incredible tool for dealing with the complexities of rising energy demand in the future, we should be more mindful of how to use it specifically and wisely. Both underdeveloped and emerging countries, like developed countries, should begin developing policies to make their grid systems smarter and cleaner. There is an adage that says, “cleaner electricity is smarter electricity.” And, in this age of environmental degradation, we need a reasonable amount of renewable energy. Smart grid infrastructure assists in the interconnection of national networks. Smart grid systems can transmit energy through a smart web infrastructure, with far-flung transmission and delivery guaranteeing the system’s perfection. Under the English Channel, an IF 2000 Under Sea connection creates 2000MW HVDC submarine interconnection that ties up the national grids of France and the United Kingdom. Via a bidirectional transmission and delivery network, this interconnection network assists all countries in meeting their increased energy demand as peak demand rises. Tables 6 and 7 present some funding and application of BC-related published work.

6. Conclusion

A SG infrastructure attack does not only affect consumers; it also affects energy providers’ profitability. There are several risks to the SG networks that could turn into attacks depending on the adversary’s benefit. To make identifying and analyzing such attacks easier, we have divided them into five categories. The paper also looks at and reports on countermeasures for all types of assaults. Extensive research is also required to ensure that IoT and big data on the SG system can protect against adversarial threats without compromising customer trust in the utility provider or dramatically inconvenience. Based on the survey, we still found some research gaps; those are required more concern and improvement for a sustainable BC-based SG and energy trading system. To address issues and challenges, the further improvements and recommendations are as follows: (i)The BC in different SG systems needs efficient cryptographic schemes(ii)BC network required penalty and incentive mechanisms(iii)Advance privacy, security, and data communication exchanges(iv)The BC-based SG system is required to keep penalty/reward policies(v)Interoperability limitation among the SG process(vi)Game theory, cognitive modeling, and deep learning need to add a standard processing technique for benchmark and validation(vii)SG energy sources required optimal allocation(viii)Renewable/storage energy system required communication and advance metering for integration with SG, control, and monitoring(ix)Energy management systems are required considering the burden and computational complexity to design and implement(x)SG required more focus to handle uncertainty: source intermittency, weather condition, electric vehicle/plug-in-electric vehicle driving pattern, impulsive human behavior during the load connection, and disconnection

Data Availability

All related data is available in the manuscript.

Conflicts of Interest

The authors declare no conflict of interest.


This work was supported by the Universiti Kebangsaan Malaysia (UKM) under the FRGS/1/2020/ICT03/UKM/02/6 and GP-2021-K023208.