The behavior of agents to ensure financial security on the basis of game theory was analyzed, the winning strategy taking into account risk and uncertainty was determined. Using Data Mining the useful functions of this technology were identified to ensure financial security: suspicious transactions determination, credit risks analysis, client account reliability analysis, financial indicators predicting and risks control. A comparison was made of the assessment of the effectiveness of various data mining algorithms on the nature of financial transactions and decision-making procedures in the financial security system. It was proved that the development of information technology has created a whole range of vulnerabilities in the financial system, in particular, has transformed the form of money in modern conditions - the emergence of a cryptocurrency. The influence of the formation and development of cryptocurrency on financial security at all levels of the economy: micro and macro was analyzed.