Abstract: The article is devoted to the definition of cryptocurrencies and the peculiarities of their use as an alternative means of electronic payments. The need to study this aspect of cryptocurrencies is due to the fact that since the first cryptocurrencies appeared, although this phenomenon has become entrenched in modern economic life, it has not been unambiguously assessed by the scientific community.

Existing discussions on the role of cryptocurrencies in the financial system have led to insufficient attention being paid to their actual characteristics and peculiarities of practical application. This is important given that in Ukraine, the issues of state regulation of cryptocurrencies and their place in the domestic financial and payment system have not yet been fully resolved.The purpose of this study is to examine the basic features and essence of cryptocurrencies, their main types and the technological basis of their functioning. The review in this paper of the current state and prospects for the development of cryptocurrencies, as well as the technologies on which they operate today, made it possible to deepen the understanding of this relatively new phenomenon for the economy in the current environment.

The article discusses various technologies for storing transaction data. Among them, such types of blockchain technology as public and private (closed blockchain on which such altcoins as Ripple operate) are separately distinguished. The article also considers those cryptocurrencies that use other (alternative) technologies for verifying, recording, storing transaction data, as well as managing both them and the network. Among the variety of such technologies, given the purpose of the study, the following were separately identified: 1) Directed Acyclic Graph (DAG) technology, 2) Holochain technology, and 3) Centralized Ledgers technology. The author also traces how the emergence of these technologies affects the understanding of what can be called a cryptocurrency today.

The analysis conducted in this article shows that: 1) Cryptocurrency is a digital asset that plays the role of a parallel means of exchange, payment and accumulation among a limited number of persons and has cryptographic security. It exists only in digital form in the corresponding payment system. 2) Today, cryptocurrencies operate not only within peer-to-peer networks. There are also those that operate in multi-peer networks. 3) Today, there are cryptocurrencies that are subject to central regulation by a single regulatory authority. 4) Today, not all cryptocurrencies use a decentralized public ledger (blockchain); 5) Today, there are cryptocurrencies whose networks can function without the use of mining. 6) The main feature of cryptocurrencies is their cryptographic security.