Complex Security System of a Regional Corporate Network Based on the Osi Model and the "Defense-in-Depth" Model

The strategy of the EU Agency for Cybersecurity (ENISA) and Ukraine's Cybersecurity Strategy aims to develop and implement new approaches, methodologies, and technologies for addressing cybersecurity challenges in critical infrastructure sectors, particularly in ensuring data confidentiality within corporate networks. An analytical review of well-known corporate network security methods and technologies has been conducted in secure data exchange and storage; enhancement of security models, tools, and information protection systems; and the application of machine learning methods and neural network technologies for anomaly detection in corporate networks. A comprehensive security system for a regional corporate network is presented based on the seven-layer OSI model, the "defense-in-depth" model, and the "threat–security technologies" concept, which is universal for different network topologies and enables the design of information protection systems at each OSI layer by regulatory requirements. Software for the cryptographic protection of information at the transport network layer of the OSI model has been developed using the symmetric block cipher AES-256, implemented in Python. This solution is practically realized through the OpenVPN protocol and TLS transport layer technology, ensuring a high level of data confidentiality in regional corporate networks.