A cryptocurrency is an encrypted data string that denotes a unit of currency. It is monitored and organized by a peer-to-peer network called a blockchain, which also serves as a secure ledger of transactions, e.g., buying, selling, and transferring. Unlike physical money, cryptocurrencies are decentralized, which means they are not issued by governments or other financial institutions. Cryptocurrencies are created (and secured) through cryptographic algorithms that are maintained and confirmed in a process called mining, where a network of computers or specialized hardware such as application-specific integrated circuits (ASICs) process and validate the transactions. The process incentivizes the miners who run the network with the cryptocurrency. The advantages of cryptocurrencies include cheaper and faster money transfers and decentralized systems that do not collapse at a single point of failure. The disadvantages of cryptocurrencies include their price volatility, high energy consumption for mining activities, and use in criminal activities. Popular cryptocurrencies are; Bitcoin, Ether, Litecoin and Monero. Bitcoin is the most popular and valuable cryptocurrency. In the world there is a whole range of crypt valued payments and the exchange of entire business processes through the same. There is still a certain disparity in Croatia in terms of their use, and there is a lesser possibility of their use. This thesis describes in detail the cryptocurrency markets and the most important currencies in that market, as well as capital markets, but also the cyber security of cryptocurrencies. Last part of the work is primary research which examined respondents opinions on knowledge of cryptocurrencies. The obtained results were analysed and presented in graphs. Keywords: cryptocurrencies, cryptocurrency