The theme of the final work is the application of the cryptocurrency. Cryptocurrency is a digital media exchange, and the first cryptocurrency bitcoin was created in 2009. Cryptocurrencies are spread all over the world, and in the most countries they are not regulated by law, furthermore in some they are prohibited. Bitcoin, like other cryptocurrencies, was built on blockchain technology, which allows a virtual coin to be used only once. Even though, there are more than 5500 cryptocurrencies, the most used are the bitcoin, ethereum and ripple. In etherea there is also a clever contract that allows payment only after the service has been agreed and, if it is not done, the money is returned to the account of the sender. There are also different cryptocurrency wallets where you can see information about a particular cryptocurrency, payments, account payments, and other relevant items.