# Addressing ZSM Security Issues with Blockchain Technology  
[PERSON]  
1 Department of Industrial Design and Production Engineering, University of West Attica, 122 43 Attica, Greece 1  
crucial to orchestrate the performance of the individual NSs [9; 10]. Considering that modern networks must support applications with very different QoS requirements, the ability of flexible and agile provisioning of high availability, ultra-low latency and 100% coverage is of high importance [11; 12] and SDN/NFV-enabled networks play a crucial role in this [13; 14]. Massive, seemingly infinite capacity, imperceptible latency, ultra-high reliability, personalized services with extreme improvements in customer experience, global web-scale coverage, and support for massive machine-to-machine communication are only a subset of the requirements that these deployments should fulfill. The flexibility offered by the SDN/VNF architecture opens the opportunity for NPs to enhance the utilization of their resources by the dynamic reconfiguration and allocation of workload to the different devices/resources. For given NS demands, NPs can trade resources to support NSs with predefined network characteristics when needed. To maximize the benefits of resource sharing, NPs need a framework for a highly dynamic, self-optimized resource management process. Additionally, to avoid human errors and reduce the response time of the system, the resource management process should require minimum human intervention. The requirements of NPs have led the research community to the development of the Zero-touch network and Service Management (ZSM) standardization, kicked off by the ETSI (the European Standards Organization) in 2017 [15]. The pivotal deployment of 5/6G and network slicing gave birth to the need for a radical change regarding the management and orchestration of modern networks and services. More specifically, there is a need to handle: (a) the increased overall complexity of networks derived from their transformation into programmable, software-driven, service-based and holistically managed architectures, (b) the unprecedented operational agility (i.e., real-time management of NS) required to support new business opportunities enabled by technology breakthroughs, such as network slicing. The ultimate automation goal is to enable largely autonomous networks which will be driven by high-level policies and rules; these networks will be capable of self-configuration, self-monitoring, self-healing and self-optimization without further human intervention. Besides the important benefits stemming from ZSM introduction, a set of security challenges are also introduced in this highly dynamic, automated resource management environment, as already pointed out by their proposers [15]. The concerns are related to the untrusted nature of modern networks where large numbers of NPs are involved and the security level of the automated mechanisms (many times powered by Artificial Intelligence (AI) and Machine Learning (ML)). Since these automation mechanisms are responsible to make important decisions regarding the management of the network, the safeguarding of this mechanism is vital for the network's well-being. These mechanisms must not be compromised, and their decisions must not be manipulated or tampered with. Although several solutions have been discussed in the ETSI documents, the complexity of the system increases as multiple different techniques are combined. On the other hand, Blockchain technology (one of the most hyped technologies in 2022) is adopted in many different use cases. The ability to establish trust in an untrusted environment, the data integrity and the transaction validity ensured in the absence of a trusted third party are the main characteristics that make blockchain attractive. To accomplish that, blockchain solutions run in a decentralized and distributed network of nodes that are characterized as public, private, permissioned and permissionless, offering different degrees of participation control.