Organizational and technical solutions for the construction of protected information and communication systems.

The paper presents the main approaches to the construction of the PKI public key architecture divided into basic, two-level, and multi-level hierarchies. Modern methods of attacks on existing public key infrastructures, protocols for building secure connections of both wired and wireless systems are considered. The basics of the class of attacks on PKI infrastructures are defined, of which the main attention is paid to the most dangerous class of attacks – man-in-the-middle (MITM-attacks). The paper provides models of various classes of MITM attacks, their details and existing methods of reducing the risks of their implementation. Existing examples of successful attacks on enterprises and various organizations that implemented MITM attack models at the application, network, and physical levels of the network interaction model are also given. For the PKI infrastructure, one of the options is its segmentation, which allows to reduce the scope of attacks on the key certification center. The paper also provides an alternative way to protect against MITM attacks using distributed micro ledger technology (DLT) to create a decentralized cryptographic key distribution system (DKMS). The solution is based on the use of micro ledgers (distributed ledger technology – DMLT). Using DMLT to create a DKMS allows protection against additional classes of MITM attacks.