Cryptocurrency for Beginners: How Crypto Works

How crypto works comes down to one idea: a public record that many computers keep in sync, so that nobody needs a bank to confirm who owns what. That record is the blockchain. The coins are not files on your phone; they are balances on the record, and you prove ownership with a secret number called a private key. Everything else, from wallets to exchanges to fees, builds on that.

The blockchain in plain terms

A blockchain is a list of transactions grouped into blocks, each linked to the one before it. Thousands of independent computers, called nodes, hold copies and check every new block against the network's rules. Changing an old entry would mean redoing all the work that came after it and persuading most of the network to accept the altered version, which on a large network is impractical.

How a network settles on the next block varies. On Bitcoin it is proof of work, a race among miners to solve an expensive puzzle, as our Bitcoin guide explains. Ethereum and many newer chains use proof of stake, where validators lock up coins as a deposit they can lose if they cheat. Either way, the result is a shared history that is very hard to rewrite.

Coins, tokens and stablecoins

• Coins are native to their own blockchain: bitcoin on Bitcoin, ether on Ethereum. They pay the network's fees.
• Tokens are created by smart contracts running on an existing chain. One chain can host thousands of tokens, from project tokens to digital collectibles.
• Stablecoins are tokens pegged to an outside value, most often the dollar, with an issuer promising reserves behind them. USDT is the best known; read what USDT is for how it works and where it can fail.

Anyone can create a token in minutes. The existence of a token, a website and a price chart tells you nothing about whether a project has any value.

Keys, addresses and wallets

Every wallet is built on a pair of keys. The public address, derived from your public key, is what you share to receive funds. The private key signs transactions and must never be shared. Most wallets turn the private key into a recovery phrase of 12 or 24 words; anyone who has those words can take everything in the wallet from any device.

Custodial or self-custody

When you keep crypto on an exchange, the exchange holds the keys and your balance is an entry in its own database. That is convenient and allows password resets, but you depend on the company staying solvent and honest. In a self-custody wallet, either an app on your phone or a dedicated hardware device, you hold the keys. No firm can freeze or lose them, but if you lose the recovery phrase, nobody can help you.

A common middle path is to keep small, active amounts on a platform and move longer-term holdings to a wallet you control, writing the recovery phrase on paper and storing it somewhere safe offline.

Buying, sending and paying fees

Most people buy their first crypto on a centralised exchange or app, paying by bank transfer or card. There are three layers of cost to watch: the platform's trading fee or spread, the payment method (card purchases are usually the most expensive), and the network fee paid to miners or validators whenever coins move on-chain.

Network fees vary with how busy the chain is. Sending USDT on one network can cost cents while the same amount on another costs several dollars at busy times. Exchanges often charge a flat withdrawal fee that includes the network fee, which hits small withdrawals hardest.

Before sending anything, check three things: the address, the network, and whether the receiving wallet or platform supports that exact network. Many wallet addresses look alike, and some scams rely on planting a similar-looking address in your transaction history. Send a small test amount first when the destination is new.

Worked example (illustrative figures)

You buy $500 of a coin through an app that charges 1.5% for card payments. That is $500 × 1.5% = $7.50 before you start. Withdraw it to your own wallet with a flat fee of $4 and you have spent $11.50, or 2.3% of the stake, before the price has moved at all.

How crypto works when you press send

Following a single transfer shows the whole system at work. Say you move USDT from an exchange to a wallet on your phone:

1. You copy the receiving address from your wallet and choose the matching network on the exchange's withdrawal screen.
2. The exchange checks your security settings, deducts the withdrawal fee and signs a transaction from one of its own wallets.
3. The transaction is broadcast to the network, where nodes check the signature and the balance.
4. A miner or validator includes it in a block. Your wallet shows it as pending, then confirmed as more blocks follow.
5. The balance now sits at an address whose private key only your wallet holds.

Transfers between two customers of the same exchange often skip the blockchain entirely: the exchange simply updates its own records, which is why they can be instant and free. That convenience is also a reminder that the coins never left the exchange's control.

Staking, lending and "earn" products

Many platforms offer to pay a return on coins you hold. The sources differ, and so do the risks:

• Staking commits coins to help secure a proof-of-stake network in return for rewards paid in that coin. Rewards can fall, coins may be locked for a period, and validators can be penalised for faults.
• Lending passes your coins to borrowers, often traders, in return for interest. If borrowers default or the platform mismanages the funds, you can lose the principal; several crypto lenders have failed this way.
• Liquidity and yield schemes in decentralised finance add smart-contract risk, where a flaw in the code can be exploited.

A yield is paid for taking a risk. The higher the advertised rate, the harder it is worth looking for where that risk sits.

From crypto back to cash

A crypto cash-out usually means selling for a regular currency on an exchange, then withdrawing to a bank account in your name. Expect identity checks, possible holding periods for new accounts and withdrawal fees. Peer-to-peer sales and cash-in-person trades carry much higher risk of fraud and of receiving money linked to crime. Converting to a stablecoin is not the same as cashing out: you still hold a token that depends on its issuer.

In many countries selling, swapping or spending crypto can create a taxable gain. Keep records of every purchase and sale, including fees.

The risks that matter most

• Volatility: falls of 50% or more from a peak have happened repeatedly, even in the largest coins.
• Platform failure: exchanges and lending firms have collapsed, freezing customer balances for years.
• Irreversible mistakes: a transfer sent to the wrong address or network is usually gone.
• Scams: fake apps, investment "mentors" met online and recovery services that charge fees to retrieve stolen coins. See how to spot trading scams.
• Regulation: rules differ by country and change. UK firms may not sell crypto derivatives to retail consumers, and UK and EU caps limit retail crypto CFD leverage to 2:1 where they are permitted.

If you do decide to buy, compare platforms carefully using our ten checks, and calculate the effect of fees with the crypto profit calculator.

Sources

• UK Financial Conduct Authority, ban on crypto-derivatives for retail consumers
• European Securities and Markets Authority, CFD leverage limits