Background. Blockchain technologies are one of the most relevant examples of computer science today. Blockchain technologies have a lot of both existing and theoretical applications. Given the speed of development of this sub-industry, the standards by which it will operate are far from ideal and there are regrettably few peer-reviewed scientific articles on this topic. Therefore, there will be links to current security standards in the industry and to the results of various events to identify and test vulnerabilities in these algorithms, as well as links to real cases and articles on the theory of algorithmization. This work will explore and test several technologies and standards in terms of information security concepts and risk assessment, as well as the use of blockchain, including smart contract technology using the example of Non-Fungible Tokens (NFT) and decentralized finance, in the application, and the risks associated with it. This paper explores the question of how secure is the current level of NFT technologies and decentralized finance, in particular what problems of Accessibility and Integrity do exist in Blockchain Projects? It is proposed to answer this question by studying cases of recent years, as well as checking the performance of some exploits, some of which have been around for a couple of years and are still an urgent problem. In this work, a blockchain application is a part of a blockchain project that is the implementation of blockchain technology in practice, together with the architecture, depending on the purpose of the project, such a combination is called a blockchain project.Objectives. The purpose of this work is to study the security of the practical implementation of blockchain projects, using the example of decentralized finance, smart contracts in the Ethereum blockchain, since they are the most common. Particular attention is paid to the centralized approach to the use of blockchain technology in practice on the example of the Ethereum blockchain anddecentralized finance.Methods. Methods include multivocal literature review, Proof of Concept evidence-based approach using several vulnerabilities as an example, as well as a review of current case studies of blockchain projects in the period from 2020 to 2022.Results. The result of this work is the answer to research questions, namely the found correlation of the use of a centralized approach to the implementation of blockchain projects in practice and the vulnerabilities found associated with this approach. Based on the results of the work done, it was concluded that the current level of security of blockchain technologies working with smart contracts is unsatisfactory given the number of unresolved problems regarding the current capitalization of the industry / <p>Defence was held online</p>