BLOCKCHAIN PROTOCOL STUDY
Blockchain has great advantages over existing payment systems (bank cards, electronic money, etc.), such as decentralization and auditing capacity. There is a wide range of blockchain applications, ranging from cryptocurrency, financial services, risk management, the Internet of things and ending with public and social services. A number of studies had focused on the use of blockchain technology in various applications. We are doing research of blockchain technology soundness. In particular, this article focuses on analyzing the safety of using a blockchain, represents typical attacks on a protocol, examines blockchain applications and discusses technical problems, as well as recent innovations in solving difficult problems. It also provides an analysis of the two most popular cryptocurrencies and smart contracts, as well as the safety problems associated with them.