Study of Cryptographic Security of Computer Networks

The article examines modern aspects of cryptographic protection of computer networks, which are critically important in the context of growing information threats and cyberattacks, in particular in the context of military operations in Ukraine. The key tasks related to ensuring the confidentiality, integrity, and availability of information, as well as the challenges facing cryptographic systems in the context of the rapid development of computing power and attack methods, are considered. The article contains an analysis of the historical development of cryptography, starting from its fundamental principles laid down by Claude Shannon, to modern methods such as symmetric and asymmetric encryption, hash functions, digital signatures, and public key infrastructure (PKI). Classical algorithms, including DES, 3DES, AES, RSA, ECC, as well as standards that demonstrate high efficiency in ensuring information security, are considered. A comparative analysis of these algorithms is conducted, their strengths and weaknesses are identified, in particular, taking into account modern challenges such as attacks based on machine learning and the development of quantum computing. Particular attention is paid to the latest threats, including Side-channel and Fault injection attacks that exploit side information or errors in cryptographic systems. These threats are becoming especially relevant for resource-intensive and embedded systems, as well as Internet of Things (IoT) devices. The article emphasizes the importance of developing post-quantum cryptographic algorithms that can provide protection against attacks that exploit the capabilities of quantum computers. It also discusses the need to improve symmetric and asymmetric encryption mechanisms, hash functions, and security protocols to increase their resistance to modern attacks. Based on the analysis, recommendations are proposed for developers of information protection systems aimed at increasing the effectiveness of computer network protection. Particular attention is paid to the implementation of integrated solutions that combine symmetric and asymmetric encryption, digital signatures, and modern cryptographic protocols to ensure multi-level security