What is Cryptocurrency?

Cryptocurrency is a digital asset whose ownership and transfers are secured by cryptographic signatures and recorded on a distributed ledger, usually a blockchain, that anyone can verify. Where your bank keeps its own ledger of your balance, a cryptocurrency’s ledger is maintained jointly by thousands of computers following the same rules. The first and best-known example is Bitcoin, which went live in 2009.

The label now covers very different things: native coins of independent networks, tokens issued on top of other networks, dollar-pegged stablecoins and NFTs. So the first question to ask about any of them is not “what’s the price?” but “what does it do, and who controls it?”

How does cryptocurrency work?

Each user holds a private key and an address derived from it. When you send crypto, your wallet signs the transaction with that key and broadcasts it to the network. Nodes check that the signature is valid and the balance is sufficient, and valid transactions are bundled into a block.

A consensus mechanism decides which block gets added next. Bitcoin uses Proof of Work: miners compete with computing power, and the winner produces the block. Ethereum has used Proof of Stake since 2022: validators lock up ETH as collateral and can lose part of it if they break the rules. Because each block references the one before it, rewriting an old record would mean redoing every block that came after it.

That makes the ledger hard to tamper with, but it doesn’t make the data correct. A payment sent to the wrong address is perfectly valid under the rules, gets confirmed, and in most cases cannot be reversed.

How is crypto different from money in a bank?

A bank balance is a claim on an institution: the bank moves the money and can correct mistakes. Someone who controls their own keys signs transactions directly, and the network accepts anything that follows the protocol. There are no banking hours or borders, but there is usually no one to call if something goes wrong.

Not every crypto asset is equally decentralized, though. Stablecoin issuers such as Tether and Circle can freeze specific addresses, and many token contracts can be upgraded by their developers. A balance on an exchange is usually just an entry in the exchange’s internal database, with the platform holding the keys.

Coins, tokens, stablecoins and NFTs

• Coin: the native asset of a blockchain. BTC pays fees on Bitcoin; ETH pays fees on Ethereum.
• Token: issued through a smart contract on an existing chain. Sending an ERC-20 token still costs a fee in ETH. Our coin vs token guide goes deeper.
• Stablecoin: designed to track a reference such as the US dollar. Reserve quality and redemption terms vary by issuer.
• NFT: a token that is unique and distinguishable from others. Owning one does not automatically give you copyright over the artwork.

Holding a token does not make you a shareholder in the company behind it or entitle you to its revenue. What a token actually gives you should be spelled out in the whitepaper and contract documentation.

Where is cryptocurrency stored? Wallets vs exchanges

A crypto wallet doesn’t hold coins; it holds the keys that let you spend them. The 12- or 24-word recovery phrase you get at setup can regenerate those keys. Lose the words and you lose access; share them and you’ve handed over your funds.

An exchange matches buyers and sellers. If you leave assets there, the exchange controls the keys, which is convenient but adds platform risk. The collapse of FTX in 2022 is the best-known reminder of what that risk can mean. Many people move long-term holdings to a personal wallet for this reason.

When you withdraw, the network matters. A token like USDT exists on several chains, and the network you send on must match the one the receiving address supports.

How to read price and market cap

A low unit price doesn’t mean an asset is cheap. A token at $0.10 with 1 billion units in circulation has a market cap of $100 million; a $10 token with 1 million units is worth $10 million. The “cheaper” token is ten times bigger.

When reading market cap, look at circulating supply, tokens still locked for future release, and order-book depth together. In a thin market, a single large sell order can move the price sharply. Our guide to market cap and FDV covers this in detail.

What does buying crypto actually cost?

Fees add up in layers. On a $1,000 purchase, a 0.2% trading fee is $2. Withdrawing to your own wallet adds a separate withdrawal fee, and the spread between the buy and sell price takes another slice. “Zero commission” rarely means the whole round trip is free, so compare the net amount you actually receive.

What to know before you start

1. Find out what the asset is for and who can mint new units or freeze transfers.
2. Decide whether you’ll keep it on an exchange or in your own wallet, and store your recovery phrase offline.
3. Add up trading, spread and withdrawal costs before you buy.
4. Test with a small transfer first, and leave leverage, lending and cross-chain bridges until you’re comfortable with the basics.

Crypto rules differ by country, and crypto holdings generally don’t carry the deposit protection that bank accounts do. Check how your local regulator treats exchanges and taxes before you commit money.

Sources

• Bitcoin.org: Transfers on an open network
• Ethereum: Network and applications
• Ethereum: Wallets
• Ethereum: Stablecoin structures