What Is Cryptocurrency? How It Works and Where Bitcoin Fits
Cryptocurrency is a digital asset on a shared ledger, secured with cryptography. See how it works, the main kinds, the risks and where Bitcoin fits.
By Christopher Cannucciari · Published
Key takeaways
- Cryptocurrency is a digital asset recorded on a shared ledger and secured with cryptography, so no bank has to sit in the middle of a payment.
- Bitcoin, launched in 2009, was the first. “Crypto” is the whole category, and Bitcoin is one member of it.
- Most crypto is not a claim on anyone. You hold keys instead of an account, transfers run at any hour, and a confirmed transfer generally cannot be reversed.
- The main kinds are coins on their own chain, tokens on another chain, stablecoins, smart-contract platforms and meme coins. Quality varies enormously.
- Prices swing widely and scams are common. Bitcoin is often treated separately because of its age, fixed supply, proof of work and lack of an issuer.
What is cryptocurrency?
Cryptocurrency is a digital asset that is recorded on a shared ledger and secured with cryptography, so that people can hold and transfer it without a bank in the middle. Many computers keep the ledger instead of one company, and the rules for adding to it are public.
Compare it with a bank balance. Your balance is a line in the bank’s private database, and the bank decides whether to honor a payment. A cryptocurrency balance is an entry on a ledger that anyone can read, and you can spend it because you hold the secret key that proves it is yours. Nobody has to approve the payment, and nobody can undo it for you either.
Bitcoin was the first working example, and the network began running in January 2009. What Is Bitcoin? covers it in depth. Many other cryptocurrencies have appeared since, with very different goals.
How does cryptocurrency work?
A cryptocurrency works through three parts: a shared ledger, cryptographic signatures and a network of computers that agree on the rules. If any one of them is weak, the whole system is.
The ledger is usually a blockchain, a record of transactions grouped into blocks that each point back to the one before. What Is a Blockchain? explains why that makes tampering visible. Computers called nodes check every new transaction against the rules and reject the ones that break them. Each network has its own method for agreeing on which transactions come next. Bitcoin uses proof of work, and other networks use other methods.
Wallets and keys are the part you actually touch. A wallet is software or a device that holds your keys. A private key is a secret number that lets you authorize spending, and an address, derived from a public key, is what you share to receive. When you send crypto, your wallet signs the transaction with the private key, and the network checks the signature without ever seeing the key.
Lose the key and nobody can recover the coins. Leak it and someone else can spend them. Bitcoin Wallets Explained covers the types. Many people never hold keys at all, because an exchange holds them on the customer’s behalf. That is a trade between convenience and control, which The Power of Self-Custody examines.
How is crypto different from bank money and stocks?
Crypto differs from bank money and stocks in who stands behind it, how you hold it and whether a payment can be undone. The comparison is easiest to see side by side.
| Bank money | Stocks | Cryptocurrency | |
|---|---|---|---|
| What stands behind it | A bank, and for eligible deposits at insured banks, FDIC deposit insurance | A company; a share is a claim on its business | In most cases no issuer and no promise; value rests on what buyers will pay |
| How you hold it | An account with a login | An account at a broker | Keys in a wallet, or an account at a company that holds keys for you |
| When it moves | Bank hours and settlement times | Market hours | Any hour of any day |
| Can a payment be undone? | Some can, through disputes or returns | Not once a trade has executed | Generally not once confirmed |
Two points are worth stating plainly. FDIC deposit insurance covers eligible bank deposits and does not cover cryptocurrency, and the FDIC publishes how its coverage works. And a stock has a business behind it that earns money, while most crypto has nothing equivalent. Its price depends on supply and demand.
Stablecoins are the main exception to the “no promise” rule. An issuer says each token is worth a dollar and holds reserves to back that up, which brings a company back into the picture. What Is a Stablecoin? covers how that works and where it fails.
What are the main kinds of cryptocurrency?
The main kinds are coins on their own chain, tokens built on another chain, stablecoins, smart-contract platforms and meme coins. The groups overlap, and the word tells you little about quality.
| Kind | What it is | What to watch |
|---|---|---|
| Coin on its own chain | The native currency of a network with its own ledger, such as bitcoin on Bitcoin | How the network is secured and who can change its rules |
| Token | Issued on top of an existing chain, often through a smart contract | Depends on the project that issued it and on the chain underneath |
| Stablecoin | A token designed to track a currency, usually the dollar | Reserves, the issuer and loss of the peg |
| Smart-contract platform | A network that runs programs, so developers can build applications and tokens | Software bugs and complexity |
| Meme coin | Started as a joke or around internet culture, usually with no practical function | Value driven largely by attention |
Ethereum is the best-known smart-contract platform, and its currency is called ether. Bitcoin vs Ethereum compares the two networks without picking a winner. Any cryptocurrency other than Bitcoin is often called an altcoin, and Bitcoin vs Altcoins offers a checklist for researching one. This guide recommends none.
Why is Bitcoin often treated separately from other crypto?
Bitcoin is often treated separately because it is the oldest cryptocurrency, has a fixed supply, uses proof of work and has no company or foundation issuing it. Bitcoin is a cryptocurrency, but “crypto” is the whole category, so “Bitcoin and crypto” is a way of separating one from the rest.
Track record. It has run since 2009, which makes it the longest-running and most examined network.
Supply. Its software caps the total at 21 million, on a published schedule. How Many Bitcoin Are Left to Mine? lays that schedule out.
No issuer. Many other coins have founders, companies or foundations that can change the rules, sell large allocations or fail. Nobody issues bitcoin.
Proof of work. Bitcoin’s security rests on computing work, which is why mining exists. Other networks secure themselves differently.
None of this makes Bitcoin risk-free, and it does not make every other coin a poor idea. It means the word “crypto” tells you little about what a particular coin is, so each one has to be judged on its own design.
How do people use cryptocurrency?
People use cryptocurrency to hold it as an investment, to send money, to move dollars through stablecoins and to run applications on smart-contract platforms. Reasonable people disagree about which of these matters most.
Sending is where crypto differs most from older systems: it works across borders at any hour, though fees and waiting times vary. Paying for everyday purchases directly is still uncommon in the US, and spending is generally treated as a sale. How to Spend Bitcoin lists the real routes. For US federal tax purposes the IRS treats crypto as property, which is why How Is Bitcoin Taxed in the US? matters before you spend or trade.
What are the risks of cryptocurrency?
The main risks are volatility, scams, custody problems, irreversible mistakes and changing rules. They are as much a part of crypto as the technology is.
- Volatility. Prices can fall sharply and have done so many times. Why Is Bitcoin So Volatile? explains why.
- Scams. Fake exchanges, impersonators, giveaways and “guaranteed return” pitches target newcomers. Common Bitcoin Scams and How to Spot Them shows the patterns.
- Custody. Coins left with a company depend on that company staying solvent and honest. Coins you hold yourself depend on your backups and habits.
- Irreversibility. A payment to the wrong address generally cannot be recovered, and no customer service line can fix it.
- Rules and taxes. How different coins are regulated differs and changes, as Is Bitcoin Regulated in the US? describes.
- Failed projects. Many cryptocurrencies fade away or turn out to be fraudulent.
Is Bitcoin Safe? separates these risks in more detail. If you are weighing real money, a qualified financial professional can help you judge your own situation.
Where should you start learning?
Start with Bitcoin, because it is the simplest and best-documented example, and the other kinds make more sense once you have seen the original design. The Start Here path covers the fundamentals in order, and you do not have to buy anything to follow it.
Where to go next
- What Is Bitcoin? A Plain-English Introduction: the first and best-known cryptocurrency, explained from scratch.
- Bitcoin vs Altcoins: What Is the Difference?: how Bitcoin compares with other coins and how to research one.
- What Is a Blockchain? Bitcoin’s Ledger Explained: the shared ledger behind most crypto.
- Is Bitcoin Safe? The Real Risks and Common Scams: the risks stated plainly.
Frequently asked questions
What is cryptocurrency in simple terms?
Cryptocurrency is a digital asset recorded on a shared ledger and protected with cryptography. Many computers keep copies of the ledger and follow the same public rules, so people can hold and send it without a bank in the middle. You control it with secret keys, not with a bank login.
What is the difference between Bitcoin and crypto?
Bitcoin is one cryptocurrency, and crypto is the name of the whole category. Bitcoin launched in 2009 and was the first. It is often treated separately because it is the oldest, has a fixed supply of 21 million, uses proof of work and has no company or foundation issuing it. Many other cryptocurrencies make different choices.
How is cryptocurrency different from money in a bank?
A bank balance is a record in the bank's private system, and the bank can approve, hold or reverse payments. Most cryptocurrency is held with keys on a public ledger, moves at any hour and generally cannot be reversed once confirmed. FDIC deposit insurance covers eligible bank deposits and does not cover crypto.
What are the main types of cryptocurrency?
The main kinds are coins that run on their own chain, tokens built on another chain, stablecoins that aim to track a currency such as the dollar, smart-contract platforms that run programs, and meme coins. The kinds overlap, and quality varies a great deal within each.
What are the main risks of cryptocurrency?
Prices can swing sharply, scams are common, and mistakes are usually permanent because transfers cannot be undone. Keeping coins with a company adds the risk that it fails, and holding your own keys adds the risk that you lose them. Rules and taxes also apply and can change.
