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The 6G networks are under theoretical and research exploration by both the academia and industry. The 6G networks are a natural evolution step of the 5G networks, which are currently undergoing extensive deployment globally. The key point indicators and the key value indicators chosen for the 5G network establishment are already marching toward the dense network penetration along with excessive machine-to-machine communication, which will find further extensions within the 6G network. The sensor-based machine-to-machine communication with cloudification, softwarization, and virtualization of the different network entities will pose a great challenge for the network engineers. This excessive machine-to-machine communication has found a great enabler in the form of blockchain and artificial intelligence (AI)-based mechanism for the proposed 6G networks. This chapter addresses the security and privacy issues within the 6G networks in view of the ultradense network penetration in comparison with the 5G networks. The chapter also highlights manner in which these issues can be addressed with the blockchain-based data security schemes. Moreover, it is also pointed out that these schemes can be made robust by incorporating artificial intelligence which provides swift decision making at the machine end.
Department of ECE, KLE Technological University, Dr. M. S. Sheshgiri College of Engineering and Technology, Karnataka, India
Rochak Bajpai*
Opto-Electronic Research Group, Department of ECE, KIET Group of Institutions, Delhi NCR, India
Shailendra Kumar
Department of ECE, Integral University Lucknow, UP, India
Jyoti Tripathi
Department of CSE, G.B. Pant DSEU, New Delhi, India
Shree Prakash Singh
Department of ECE, Netaji Subhas University of Technology, New Delhi, India
*Address all correspondence to: rochakbajpai@gmail.com
1. Introduction
The evolution of communication is an age-old phenomena, which affects the humanity in multiple ways. The wireless communication speeds up the way of transferring information among man/machine through different generations. The first generation of wireless communication enabled digital voice transfer between two people. This further progressed via the second, third, fourth, and fifth generations, which aimed to transfer data among man/machine [1, 2]. Each generation, up to the fourth generation, of wireless communication system contributed in term of novel services, in the form of different types of data transmission rate (bandwidth), as summarized in Table 1. Services are offered with each generation scaling to higher data transmission rate with innovative addendum of applications in the services.
Different generation of communication: a comparison.
The fifth-generation (5G) wireless communication system has changed the entire landscape of utility of communication as it involves massive machine-to-machine communication in terms of sensor-based communication, intelligent spectrum utilization, and low latency with an emphasis on the connectivity anytime anywhere [3]. 5G communication also paves way for the application of network services not only for data transfer but also the manner in which the data are used in real-time basis for day-to-day decisions as well as forecasting about the future decisions. However, the versatile applications of the communication technologies, with innovative demands from the users, force the communication paradigm to design and develop new set of standards, which not only cater to the demands of the customers but also satisfy the advanced expectations from the network designer/engineer.
The next generation, that is, sixth-generation (6G) wireless communication system, is envisaged to be unique and innovative as it will be more proactively involved with machines as compared to the human beings. This massive machine connectivity will demand better interpretation and understanding in regard to trust, security, and privacy from man/machine perspective [4].
In this chapter, we investigate the details of the 6G communication paradigm and the manner in which it will be implemented simultaneously addressing the various challenges. The 6G communication paradigm is discussed in Section 2. Section 3 elaborates the blockchain technology for 6G communication. In Section 4, we highlight the challenges in regard to blockchain and artificial intelligence (AI). Finally, Section 5 summarizes the chapter.
With the advancement of communication paradigm and the corresponding integration with day-to-day life, the services are not only limited to leisure activities, such as video on demand and online gaming, but also to the mission critical applications, such as online financial activities, medical advises, and corporate decisions. A typical 6G communication scenario has been depicted in Figure 1. All these complex and critical activities have found use in the communication network starting with the fourth-generation wireless communication paradigm. Further, each of these activities requires their share of privacy and security to be considered for successful deployment of the services. In each generation of communication, the designers have tried to address these issues in a competitive manner; however, with the advent of 5G, it has been noticed that the softwarization, virtualization, and cloudification will be the predominant features of the next-generation network [5]. The 5G, prominently based on the interconnection of things with the support of enhanced Mobile Broad Band (eMBB), ultra-Reliable and Low Latency Communication (uRLLC), and massive Machine Type Communication (mMTC) as moving toward 6G paradigm, will also require the three support systems such as Computation-Oriented Communications (COC), Contextually Agile eMBB Communications (CAeC), and Event-Defined uRLLC (EDuRLLC) [5]. A brief about mentioned six terms is as follows:
Figure 1.
Communication scenario in 6G.
Enhanced mobile broad band: It is among the defining characteristics of 5G envisioned to support the human-centric multimedia content accessibility, services, and data, with throughput speeds that could eventually be as much as 20 Gbps under millimeter wave communication. It found its application with high population density over smaller area [6].
Ultra-reliable and low latency communication: It is another defining characteristic which is based on the premise of low latency, high throughput, and more availability. Numerous applications, such as high-frequency trading, remote surgery, and autonomous vehicle, demand communication system with minimal time delay, with strong reliability and availability. It introduces new horizon for emerging technology market with sophisticated delivery system for public services [7].
Massive machine-type communication: It is an important characteristic associated with wireless connectivity to tens of billions of machines with low latency, strong reliability, and availability. The major challenge is scalability with efficient connectivity among a large number of devices transmitting very short packets, which is not done typically with cellular system-designed human-type communications [8].
Computation-oriented communications: With the availability of unprecedented voluminous digital data, tools, memory storage, and processing power, the communication science is moving toward a new realm where we use the big data to study the communication science in social context. It is envisaged to be an interesting step in the application of 6G [6].
Contextually agile eMBB communications: With ever-expanding device domain, it is imperative to provide network connectivity with possible minimum delay, maximum reliability, and availability. Under many conditions, the response of device is not adequate and results in poor quality of service. This demands parameter adjustment in such a fashion that optimizes the overall performance. Such type of adjustment requires detailed deep analysis of the network and the machine connected through it, which will be the definitive feature of upcoming 6G.
Event-defined uRLLC: In the context of 5G, we observed that the strong reliability and low latency are the required features, but from the key performance indicator perspective, it is still lacking its applicability. It has been further fixed with proposed 6G upgradation based on the specific use case and the requirement of low latency and scaled up reliability and availability.
In view of the COC, CAeC, and EDuRLLC, 6G network will further drive the intelligent network orchestration and management and will demand that the performance key points be more stringent with a strong focus on the security and privacy of user [9]. A brief tabular representation is presented in Table 2 for reference, and as summarized below, the detailed description about different key performance indicators can also be found in [10].
Data rate: Maximum limit of data transmission rate up to 1 Tbps is envisioned for proposed 6G services. User-experienced data rate guaranteed at 95% of user locations is expected to reach 1 Gbps [9].
Spectral efficiency: The maximum spectral efficiency is proposed to reach up to 60bps/Hz, with improved multiple-input and multiple-output antenna technology and advance modulation schemes. The spectral efficiency at the individual user level is supposed to approach 3 bps/Hz. It is expected to develop optimum broadband connectivity in the case of high mobility as it will not be supported by older generation of wireless network [9].
Wide bandwidth: In order to support high data rate, the high bandwidth is inevitable. It promotes the use of millimeter wave and visible light channel to support bandwidths up to 100 GHz [11].
Enhanced energy efficiency: It is directed to have better energy efficiency at user equipment level and at the level of transmission efficiency. It is projected that the 6G technology will reach the energy efficiency of Terabits’ order per second per Joule and that demand careful crafting of energy-efficient communication strategy [9].
Ultralow latency: As per the proposed bandwidth greater than 10 GHz, the latency should be less than 0.1 ms with variation in latency less than 1 μs [11].
Extremely high reliability: As the proposed structure of 6G supposed to be extensively used for man/machine communication with strong flavor for automation. Thus, a very high degree of reliability is needed for such safety and mission critical applications.
2.1 Privacy and security issues in sixth-generation communication paradigm
With network applications including sensors and internet of things (IoT), 5G communication network categorically expands the services by leaps and bounds [4, 12]. A typical communication scenario is presented in Figure 2. This proliferation of network services with IoT devices presents a unique challenge for the network operators with regard to the security of the system. The concerns arise due to the fact that security at the hardware level is less trodden path [13], and moreover, until recently, few policy-level decisions have been taken to address this issue [14]. In the 6G paradigm, the role of network-based services and applications across the horizon seem inevitable—a continuation from 5G network paradigm. The increasing cloudification with IoT-enabled sensors-based components at the edge network possesses new set of challenges in the security landscape of network; for example, the different sensors prone to malware attack can be easily targeted by the intruders/hackers to access the data which can create havoc in the entire system. This is due to the reason that inherently, network security is supposed to be a network layer issue with little or no consideration of the data link or the physical layer design approach.
Figure 2.
Next generation network scenario.
The privacy consideration is another very vital issue, which occurs due to the large amount of information which is being shared on the network, and there is a lack of threshold to identify how much information from a person should be received so that it cannot affect the privacy. Another important aspect is that of trust which arises as the edge network is filled by different sensor nodes, and hence, it is demanding to identify the trustworthy node for information/data exchange.
Specifically, protection of privacy is a key requirement and a principle feature in the wireless communications in the envisioned era of 6G, which will pose three key challenges, namely: (i) data exchange with large number of small chunks, to harness the energy efficiency in 6G, will compromise the peoples’ privacy with over exposure of information to the government and different business enterprises; (ii) as the intelligence moves to the edge of the network result in sophisticated computation at the mobile devices, resulting in increase in the threat of attacks. This will impose a new set of requirement of establishing a privacy protection mechanism in the already resource constrained device, that is, mobile device; and (iii) maintaining a balance between performance of high-accuracy service requirements and the protection of user’s individuality will be highly required. Also, location information and identities will be demanded to realize many services and that will need judicious consideration of right to access the data, issue of ownership, supervision, and follow-up of regulatory framework for privacy protection. An evolution sketch is depicted in Figure 3. In this regard, AI and machine learning (ML) techniques will impact the privacy in the following two ways: (i) The correct application of ML can resolve the privacy issue in 6G, and (ii) on the other hand, privacy violations may occur on the ML attacks. Therefore, trust, privacy, and security are the major challenges, which need to be addressed by the 6G network to provide optimum services to the end users. The possible solutions of earlier-discussed challenges are found from the technology such as AI and blockchain [11, 15].
Figure 3.
Evolution of security landscape from 4G to 6G [9].
Blockchain is a form of distributed ledger technology, which shows promising flair to realizing advanced internet of everything (IoE) applications for the 6G communication regime. Blockchain builds trust among the networked applications by establishing a distributed database, or ledger, to collect the transition of state of all the participating nodes as data blocks. These data blocks are attributed to be self-managed and form a chronological chain, with each block associated with its previous one by their hash value. In order to maintain the order, the chain of blocks must be transparent, immutable, and traceable. Also, to develop transparency in the system, it is required that the state change of all participating nodes must be visible to every node in the network. In other words, blockchain compromises the privacy to maintain the transparency [5, 16].
3.1 Blockchain and 6G
The compromise on privacy issue to generate trust by the blockchain technology will be further exposed in the 6G communication paradigm by the aid of complex protocol and need to maintain the integrity of distributed blocks. In a nutshell, it can be inferred that blockchain introduces new attack points for the intruder, which is further aggravated in the 6G communication paradigm, as faster connectivity, and high throughput adds to the opportunity for complex and quick attacks by the adversaries [16]. Further, as discussed previously, 6G networks will face the challenge of trust measurement and the corresponding development with proper provisioning of the security of participating entity without affecting the privacy. This three-dimensional arrangement will provide multiple unique opportunities and challenges for the researchers, as presented below.
3.1.1 Opportunities
Blockchain is transparent, chronologically appended by the data blocks, and managed by participating nodes themselves. Prior to adding a new data block to the existing blockchain, the new data block needs to be substantiated and confirmed by more than 51% of already participating nodes. After verification by 51% of the nodes, the block is added to the existing blockchain. This transparency of blockchain makes it state-of-the-art technology to cultivate the trust among participating nodes, however, at the cost of privacy. Some example cases discussed in the literature, based on blockchain-dependent trust and security management, have been presented in Table 3 [17].
Example case
Description
Reference
Edge computing
Cloudification of computing resources allows the shifting of heavy/complex computations to remote servers. However, this shifting may involve classified information; hence, security and trustworthiness of participating resources need to be ascertain. The blockchain technology can be of great help to build the trust among participating servers and user devices, by ensuring integrity of all constituents.
Spectrum management involves sharing of same frequency band among multiple users. A primary user deals with leasing issue for sharing of its spectrum. Blockchain technology can help it by maintaining the lease records so that it cannot be tampered.
The next-generation communication is all about ubiquitous, reliable, and rapid connectivity where high-volume content can be cached on user devices. The advantage of device-supported content caching is that it decreases the traffic at different parts of network and results in better quality of service. As the user content may comprise sensitive information, therefore there must be mutual trust between cache requester and cache providers. The blockchain technique can bridge the trust gap between participation entities at the expense of some privacy.
The modern network is becoming more and more intelligent, resulting in independent and autonomous working with self-decision-making. This requires to take multiple critical decisions during collaboration with peer networks/service providers/infrastructure owners, etc. Blockchain can help to create a better marketplace based on trust function at the cost of privacy of participants.
We highlight that recently, blockchain has gained the highest attention in telecommunication industry. The added advantages of blockchain, such as disintermediation, immutability, non-repudiation, and proof of provenance, integrity, and pseudonymity, are particularly important to enable different services in the 6G networks with trust and security. The use of AI/ML, and other data analytic technologies, can be a possible source for new attack vectors. Since data are the fuel for AI/ML algorithms, it is crucial to ensure their integrity and provenance from the trusted sources. Blockchain has the potential of protecting the integrity of AI/ML data through its attributes of immutable records and distributed trust between different stakeholders, by enabling the confidence in AI-driven systems in a multitenant/multi-domain environment. While trust ushers the needed confidence for users to adopt autonomic AI-dependent security management systems in 6G networks, it may not prevent breach and failure in AI-enabled systems. Thus, to address the possible failure of AI systems, liability and responsibility must be addressed carefully. Therefore, trust with liability complement for ensuring secured service delivery in 6G networks. Further, to support the role of blockchain for complying with 6G requirements, most of the current 5G service models need to be significantly appended in sync with 6G. Lastly, blockchain is among the key candidates for privacy preservation in the content-based 6G networks.
3.1.2 Challenges
In the literature, blockchain is defined as a technology, which is entirely developed on the basis of trust among the participating machines and needs some compromise on privacy to measure/earn the trust. As 6G communication is supposed to be deeply penetrative in day-to-day life, when compared with existing fourth and upcoming 5G communication technologies, it differs not only with the software used through the typical data network, but also with the sensors that are used to capture the data such as smart wristwatch and smart phone [2, 3, 5]. It further introduces a set of unique challenges, which needs to be answered prior to the adaptation of the blockchain as a core 6G framework constituent. As we discussed previously, blockchain is based on trust creation among all the participants, which is not controlled or monitored by any outside controller. The attackers may take advantage of this self-regulatory mechanism by trying to control at least 51% of the participants. In other words, it can be interpreted as the attacker may control the network by controlling 51% of computing power of entire participating network. It is found to be majority vulnerability. Also, blockchain counts the trust at the cost of privacy, which makes participating nodes vulnerable as they need to share their details with other nodes in order to earn trust. Another proposition of interest is selfish mining, where a dubious participant earns more trust reward by compromising the privacy in comparison with the genuine participant [17]. Sybil attack is another challenge, where the intruder node creates multiple blockchain accounts to manipulate the trust function in its favor. With the expected scale of deployment of 6G network, blockchain can be the front runner in massive machine-to-machine communication, which is going to make many mission critical decisions. Therefore, the concerns need to be critically addressed by the research and the scientific community.
The massive deployment of networked machines creates a plethora of data, which is expected to increase by leap and bounds in the next generation of communication. The massive information creation and the corresponding meaningful interpretation are not possible with human efforts only, and need of machine is inevitable to process/interpret and then apply for meaningful purpose. AI along with ML is the emerging processing mechanism by which better and cost-effective decision-making can be ensured [19]. As blockchain is supposed to be the forerunner in 6G communication, AI will aid the blockchain technology to measure/monitor the trust value by mining the available information to identify malicious node within the network. Further, vision of 6G is based on the premise that the autonomous networks will perform self-x (self-configuration, self-monitoring, self-healing, and self-optimization) with limited human involvement [16, 18]. The ongoing efforts on specification development to integrate AI/ML as a native element in the futuristic networks, such as ETSI ZSM architecture necessitating closed-loop operation and AI/ML techniques with ubiquitous automation of network management operations including security, are paramount steps toward this objective [11]. Since the ubiquitous use of AI/ML will be conceived in a large-scale, distributed system for numerous use cases including network management, distributed AI/ML techniques will enforce rapid control and analytics on extremely large amount of generated data in the 6G networks. Further, in 6G, AI/ML will be spatially pushed in close vicinity to the source of data of interest, to achieve ultrasmall latency, while distributing ML functions over the network to attain performance gains due to optimized models and ensemble decision making. However, overcoming practical constraints of few network (IoT) elements, such as computational shortcomings at the edge node and intermittent connectivity of node to the server, is an open research issue to be addressed. Also, distributed AI/ML can be applied for security of different stages of cybersecurity protection and defense in 6G. The major advantages of AI/ML-driven cybersecurity are the features of autonomy, higher accuracy, and predictive capabilities for security analytics.
In regard to trustworthiness issue, an eager reliance on AI/ML on futuristic networks raises the question of whether ML components are reliable or not. This is a key issue under the consideration, when critical network functions, as well as security aspects, are all AI-controlled. As a possible solution, trusted computing resources, formal process of verification techniques, and integrity checks are tool of importance. As for the visibility, to control and account, visibility is crucial. Security experts and monitoring authority require neat and intelligible insight into AI-based schemes, as compared to the blackbox operation. An open issue is to monitor for security-breached AI incidents in a timely fashion so that time-bound preventive and corrective measures can be approached.
The 6G communication paradigm is at the discussion level with some expected goals and decided key performance indicators. Some of the technologies such as blockchain, as per the application, have been identified as a probable candidate for real-time deployment, however, with their own share of challenges and their solutions. This chapter presents a consolidate research survey in this direction so that further research can be undertaken in specific direction.
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