The short version
- A cryptocurrency is an entry on a public ledger (a blockchain) that anyone can check and no single company controls.
- Whoever holds the private key controls the coins; on a platform, that is usually the platform, not you.
- Prices are driven largely by demand and sentiment, so falls of more than half have happened repeatedly.
How crypto works comes down to one question: who keeps the record of who owns what? In a bank, the bank does. In crypto, thousands of independent computers keep identical copies of a shared record, called a blockchain, and follow the same rules for adding to it. No single company can quietly edit the balances, and anyone can check them. That design is what makes crypto different, and it is also the source of most of its risks.
The blockchain: a ledger everybody holds
A blockchain is a list of transactions grouped into blocks. Each new block contains a fingerprint (a cryptographic hash) of the one before it, so changing an old entry would break every block that follows. Computers running the network's software, known as nodes, check each new block against the rules before accepting it.
Someone has to propose new blocks, and networks use different methods to choose who:
- Proof of work, used by Bitcoin: miners compete to solve a costly computing puzzle. The winner adds the block and earns newly created coins plus fees.
- Proof of stake, used by Ethereum since 2022: validators lock up coins as a deposit and are picked to propose blocks. Cheating can cost them part of that deposit.
Either way, the goal is the same: make rewriting history far more expensive than playing by the rules.
Keys and wallets: what "owning" crypto means
You do not hold a coin the way you hold a banknote. What you hold is a private key, a long secret number that can sign transactions for a particular address. The address, derived from a public key, is like an account number you can share. The private key is like the only signature the network will accept.
A wallet is software or a device that stores those keys. Most wallets let you back them up as a seed phrase of 12 or 24 words. Anyone who learns those words can take everything, from anywhere, instantly. No legitimate company, support desk or website will ever ask for them.
| Custodial (on a platform) | Self-custody (your own wallet) | |
|---|---|---|
| Who holds the key | The platform | You |
| If you forget a password | Usually recoverable through support | Lost for good without the seed phrase |
| If the company fails | Your coins may be frozen or lost | Not affected |
| Main risk | Platform failure, freezes, hacks | Your own mistakes, theft of the seed phrase |
Coins, tokens and stablecoins
A coin is the native asset of its own blockchain, such as bitcoin on Bitcoin or ether on Ethereum. A token is created by a program running on someone else's blockchain; thousands exist on Ethereum, Tron and other networks. Some represent votes in a protocol, some are used inside apps, and many have no clear purpose beyond speculation.
Stablecoins are tokens designed to hold a steady value, usually one US dollar. The largest is USDT (Tether). They are widely used to park money between trades and to move value across platforms, but they depend on the issuer actually holding the reserves it claims.
How you buy crypto, and where it sits afterwards
Most beginners buy through a centralised platform: you pass identity checks, deposit money, and buy from other users on the platform's order book or directly from the company. The coins then sit in the platform's wallets and your account shows a balance. You can usually withdraw to your own wallet, paying a network fee.
The alternative is a decentralised exchange, a program on a blockchain that swaps tokens directly from your wallet. There is no company holding your funds, but there is also nobody to call if you approve a malicious contract or buy a worthless token. Before trusting either, read how to choose a platform and what the costs look like.
Why crypto prices swing so much
Most crypto assets produce no earnings, so there is no profit figure to anchor the price. Value rests on how many people want to hold the asset, how much of it exists and what they expect others to pay later. That makes prices unusually sensitive to news, interest rates, regulation, large holders selling, and the general mood on social media.
The recurring result is the crypto bubble: prices rise fast, rising prices attract new buyers, new buyers push prices higher, and then some trigger reverses the loop. Falls of 50% to 80% from a peak have happened more than once in Bitcoin's history, and far worse for smaller tokens, many of which never recovered.
The arithmetic of a fall is harsher than it looks. Take an illustrative $1,000 holding that drops 80% to $200. To get back to $1,000 it must rise fivefold, a gain of 400%. A 50% fall needs a 100% gain to recover.
Network fees, staking and "earn" products
Every blockchain transaction pays a fee to whoever adds it to a block. On busy networks the fee rises because users bid for limited space, so sending the same token can cost pennies one day and several dollars another. Platforms usually pass this on as a withdrawal fee, sometimes with a margin added.
On proof-of-stake networks, holders can lock coins to help secure the network and receive rewards, known as staking. Platforms also offer "earn" products that pay a yield on deposited crypto. The yield has to come from somewhere: network rewards, lending your coins to other users, or riskier activities. When several crypto lenders collapsed in 2022, customers who had deposited coins for yield found themselves among the creditors. Before locking anything, ask where the return comes from, whether you can withdraw at any time, and what happens to your coins if the platform fails.
Signs of froth worth noticing
- Prices rising mainly because prices are rising, with no change in how the asset is used.
- Friends and relatives with no interest in technology asking which coin to buy.
- Heavy use of leverage, with large liquidations on sharp moves.
- New tokens launched daily with names borrowed from whatever is popular.
None of these tells you when a turn will come. They are reminders to size any purchase as money you could lose entirely. Our guide on comparing coins covers the checks to make on any individual token.
Common beginner mistakes
- Sending on the wrong network. USDT exists on several blockchains; sender and receiver must use the same one.
- Trusting a screenshot. A fake platform can show any balance it likes. The test is whether you can withdraw.
- Using leverage early. Crypto futures can liquidate a position after a modest move. In the UK and EU, retail CFD leverage on crypto is capped at 2:1, and the UK bans crypto derivatives for retail consumers entirely.
- Ignoring fees. A small trading fee on each side, plus spread and network fees, raises the price you need just to break even. The crypto profit calculator shows the effect.
Beginner questions
Is crypto real money?
Some countries treat certain crypto-assets as property or financial instruments, and a few accept Bitcoin in limited ways, but in most places it is not legal tender. Shops and landlords are not obliged to accept it.
How do I know if we are in a crypto bubble?
Nobody can reliably call the top. Rapid price rises driven by new buyers rather than new use, heavy leverage and widespread excitement are classic warning signs, and each past bubble ended with a deep fall.
Can a crypto transaction be reversed?
Generally no. Once a transfer is confirmed on the blockchain, only the recipient can send it back. That is why checking the address and network before sending matters so much.
Sources
- Bitcoin whitepaper (Satoshi Nakamoto, 2008)
- Ethereum Foundation documentation on proof of stake
- UK Financial Conduct Authority, ban on crypto-derivatives for retail consumers