The main objective of the paper is to provide an answer to the question whether new technologies such as blockchain that enter various spheres of public life are safe for users and what impact they have on national legislations. Cryptocurrencies, which are based on blockchain technology, can be used as a means of payment, investment or capital accumulation. Therefore, blockchain becomes more and more popular. The main research method used in the paper consists of the analysis of legislation and jurisprudence as well as linguistic and purposive interpretation which affects the functioning of blockchain and cryptocurrencies. The introductory part of the paper contains a general historical outline and basic principles related to blockchain technology. Real and potential threats posed by the discussed technology are also discussed in the paper as well as the question whether governments or, more broadly, the international community, offer sufficient level of protection against risks related to the use of new technologies such as blockchain and cryptocurrencies. Using blockchain to streamline logistic activities or to speed up transactions is useful in itself, but in the hands of private entities the technology may pose a risk of losing funds if not properly secured. The financial market is and should be supervised and controlled by the state which is the guarantor of economic freedom. Another vital question is whether legislators keep up with the advances in technology. It seems that the development of blockchain technology triggers development of new legal regulations. The more blockchain technology enters everyday life, the more legal documents appear in the form of case law, legal provisions, opinions etc. The role of these documents is to regulate, define and specify new technologies as they appear.