What is cryptocurrency?

In brief

"Cryptocurrency" describes digital assets whose issuance, transfer, and ownership records are secured using cryptography and maintained on a decentralized or semi-decentralized network, rather than by a bank, payment processor, or government ledger. The term is used loosely enough in everyday speech that it gets applied to things that work quite differently from one another: a blockchain's own native asset, an application-issued token built on top of someone else's blockchain, and dollar-pegged stablecoins are all commonly called "cryptocurrency," even though only some of them are designed to function as money in an economic sense.

Native coins versus tokens

A useful first distinction is between a blockchain's native asset and a token issued on top of an existing blockchain.

A native asset (bitcoin on the Bitcoin network, ether on Ethereum, SOL on Solana) is built into the base protocol itself. It is typically used to pay transaction fees, and on proof-of-stake networks it is also used to secure the network through staking. There is no separate issuer to point to; the asset exists because the protocol's rules create and track it.

A token, by contrast, is issued on top of an existing blockchain rather than being that chain's own base asset, and different chains implement "on top of" quite differently. On Ethereum, a token is typically its own smart contract: the ERC-20 standard, proposed by Fabian Vogelsteller and Vitalik Buterin in 2015, defines the common set of functions (transfer, balance lookup, and so on) that a fungible-token contract needs to implement so that wallets and applications can interact with it consistently, and each ERC-20 token is a separately deployed contract. Solana takes a different approach: rather than giving each token its own contract, Solana's Token Program is a single, shared on-chain program that every token uses, where a "mint" account represents a specific token and per-owner "token accounts" track individual balances of it. Cardano differs again: its ledger treats user-defined tokens as native, first-class assets tracked directly by the same protocol-level accounting used for its own native asset (ADA), so a basic token transfer does not require executing any smart-contract code at all, even though a script can still control minting and burning rules. In every case, a token depends entirely on its underlying blockchain's security and availability rather than being a separate network of its own, but exactly how a token is implemented, and whether that requires its own smart contract, is a chain-specific design choice rather than one universal mechanism.

How ownership and transfers actually work

Regardless of whether an asset is a native coin or a token, the same basic mechanism authorizes a transfer: whoever controls the relevant private key can cryptographically sign a message instructing the network to update its records, and the network's nodes check that signature against the account's public key before accepting the change. Ownership, in this technical sense, is not a certificate or a name in a corporate database; it is the ability to produce a valid signature for a specific account or address. This is also why the record of who owns what does not live with a company: it is maintained collectively by the ledger and its network of validating nodes, following rules set out in the protocol (see the companion article on what a blockchain is for how that ledger and its validation process work).

Examples, without turning this into a coin list

Bitcoin was designed, per its original whitepaper, as "a purely peer-to-peer version of electronic cash," allowing direct payments between parties without a financial institution in between. Ethereum's native asset, ether, functions primarily as the fee and staking asset for a general-purpose programmable network rather than as a payments-first design. Thousands of other native assets and tokens exist with widely different designs and purposes; this article deliberately does not attempt a comprehensive list or imply that any of them is a good store of value or investment, which is outside its scope.

Cryptocurrency versus conventional electronic money

Ordinary electronic money, such as the balance in a bank account or a payment app, is a liability recorded and guaranteed by a specific institution, denominated in a national currency, and ultimately backed by that institution and its regulator. A cryptocurrency, in the strict native-asset sense, is not a liability of any single institution; it exists as an entry in a decentralized ledger that no single party unilaterally controls, and its supply and issuance follow rules encoded in the protocol rather than a central bank's policy decisions.

This distinction matters for how each is regulated and how disputes get resolved. The IMF's 2016 discussion note on virtual currencies noted that these systems can offer efficiency and financial-inclusion benefits, particularly for cross-border transfers, while also creating new risks around money laundering, consumer protection, and, potentially, financial stability as adoption grows, precisely because they do not sit inside the existing framework of licensed financial institutions.

Stablecoins, briefly

Stablecoins are cryptoassets specifically designed to track the value of another asset, most commonly the US dollar, usually by holding reserves or using an algorithmic mechanism to defend the peg. They are worth mentioning briefly here because they sit in an interesting middle position: they are issued and transferred using the same cryptographic, blockchain-based mechanisms as other tokens, but they are explicitly designed to behave like currency rather than to fluctuate in value the way most other cryptoassets do. The Bank for International Settlements noted in a 2025 bulletin that stablecoin market capitalization had grown to roughly $255 billion, that two issuers accounted for around 90% of that total, and that because stablecoins move across borders on permissionless blockchains while regulation is generally organized by jurisdiction, applying a simple "same risks, same regulation" principle to them is not straightforward. This article only introduces the category; peg mechanisms, reserve composition, and stablecoin-specific failure modes are outside its scope.

Why not every cryptoasset is a currency

A significant share of what gets called "cryptocurrency" in casual conversation is not designed to function as a medium of exchange, a unit of account, or a stable store of value, the three properties economists typically use to define money. Governance tokens, for example, primarily represent a right to vote on a protocol's parameters; many tokens tied to specific applications primarily represent access rights, collateral, or a claim on a protocol's future activity rather than a currency people are meant to price goods in or hold for stability. The European Central Bank's 2019 assessment of crypto-assets concluded that, at the time, crypto-assets generally did not fulfil the standard functions of money: their prices were too volatile, and they were not widely accepted by merchants as a means of payment. Calling every cryptoasset a "currency" tends to obscure this: it is more accurate to treat "cryptocurrency" as a broad, historically established umbrella term, and to ask what a specific asset is actually designed and used for before assuming it behaves like money.

What to learn next

The companion articles on blockchain and crypto wallets cover the underlying ledger and the tools used to hold and authorize transfers of these assets, and coverage of decentralized finance extends this introduction into the applications built around cryptoassets, including how stablecoins are used within it.