Bitcoins and altcoins (other cryptocurrencies) open access to an unlimited market. More and more companies support the development of new financial technologies. Restaurants and hotels, food delivery services and the world's largest universities accept bitcoins even more willingly than their national currencies. The whole countries are introducing cryptocurrency as a means of payment in almost any field. Japan is one of the first who legalized the payment of any goods and services using bitcoin. Blockchain Clover company showed that from 148 billion dollars that were sent from the US by individuals to other countries in 2017, more than 15% of transfers were carried out using cryptocurrency. This means that blockchain technologies have already taken the 4th place at that time among all means of sending money, conceding only to such popular, but more expensive options as online services, money transfer systems and banking services.