Abstract
The article describes the use of information and telecommunication systems in public and private institutions and disadvantages for the construction of information and telecommunication systems for decentralization. The analysis of recent researches and publications on the subject of the block is conducted. The paper describes the principle of the technology, the block and the ways in which a block protects itself from attempting to make unauthorized changes or deletion of data. The expediency and perspectives of using information security technologies from the point of view of the triad of information security services as confidentiality, integrity and accessibility are considered. The rapid development of information technology is expected to rapidly increase and increase, and also threatens the information and telecommunication systems that have most of these systems. A promising direction for the construction of information and telecommunication systems is the use of decentralization. Therefore, it is important to analyze the use of Blockchain technology for the construction of decentralized information and telecommunication systems in terms of information security.