Integration of Zero Trust and Blockchain in SDN networks: An overview of threats and methods of their elimination

The purpose of the study was to identify theoretically sound methods for integrating Zero Trust and blockchain concepts to improve the overall security of software-defined networks (SDN). The research was based on the development of a theoretical network model that includes an SDN controller, switches, routers, and hosts, which used virtualisation tools such as GNS3, VirtualBox, and Docker. The theoretical basis of the study covered the analysis of key threats, including DDoS attacks, routing manipulation, insider threats, attacks on the application programming interface (API), and specific vulnerabilities of blockchain consensus mechanisms. Simulation scenarios were developed to demonstrate the potential impact of these threats on the security and performance of SDN networks. Analysis of the results obtained theoretically confirmed that the use of Zero Trust policies significantly reduces the risks of insider attacks and improves the protection of the SDN controller due to the principles of constant access verification and micro-segmentation. Integration of blockchain technologies increases the reliability of routing and traffic management, preventing malicious interference in the network infrastructure. Theoretical methods for authentication and verification of requests using blockchain significantly improve the protection of APIs and interaction interfaces. In addition, hybrid consensus algorithms have shown the potential to improve network performance and ensure its resistance to attacks. The study highlighted the importance of integrating Zero Trust and blockchain as an effective solution for eliminating a wide range of threats in SDN networks. This opens up new prospects for the protection of telecommunications systems and lays the theoretical foundation for further research and improvement of security methods. The practical significance of the study is to develop specific recommendations for implementing a comprehensive SDN security system based on blockchain technologies and Zero Trust principles. The proposed solutions can be used both in the public sector to protect critical infrastructure and in the private sector to ensure the security of corporate networks