Cryptocurrency for Beginners

How crypto works is simpler than the jargon suggests. A blockchain is a ledger. A cryptocurrency is an entry on that ledger. A private key is the only thing that can move that entry. Almost everything else, including exchanges, wallets and stablecoins, is built around those three facts.

The ledger: blocks and consensus

A blockchain groups transactions into blocks. Each block contains a fingerprint (a hash) of the one before, so changing an old transaction would mean redoing every block that followed. Thousands of independent computers, called nodes, keep copies of the ledger and check each new block against the rules.

Networks need a way to agree which block comes next. Bitcoin uses proof of work: miners spend electricity solving a puzzle, and the winner adds the block and collects a reward. Ethereum switched to proof of stake in 2022: validators lock up ETH as collateral and can lose part of it if they break the rules. Tron uses a delegated form of staking, with a small group of elected block producers. The method differs, but the aim is the same: make cheating more expensive than following the rules.

Keys, addresses and wallets

A wallet does not hold coins. The coins stay on the blockchain. What a wallet holds is a private key, a very large secret number that can sign transactions for an address. From the private key comes a public address, which you can share so others can send to you.

Most wallets let you back up your keys as a seed phrase of 12 or 24 words. Anyone with those words can rebuild the wallet on their own device and empty it. No legitimate company, support agent or website ever needs them.

Coins, tokens and stablecoins

A coin is native to its own blockchain and pays that chain's fees: BTC on Bitcoin, ETH on Ethereum, TRX on Tron. A token is created by a smart contract on an existing chain. USDT, for example, exists as a token on Tron, Ethereum and other networks, and moving it still requires the chain's native coin (or resources bought with it) to pay the fee.

Stablecoins are tokens designed to hold a steady value, usually one US dollar, by keeping reserves of cash and short-term assets. They are the main way traders park money between trades without leaving the crypto system. Our page on what USDT is explains the reserve model and its risks.

Smart contracts, Ethereum and Tron

Bitcoin's scripting is deliberately limited. Ethereum was designed to run smart contracts: programs stored on the blockchain that execute exactly as written when someone interacts with them. Tokens, decentralised exchanges and lending protocols are all smart contracts. Tron offers a similar environment and has become a busy network for stablecoin transfers.

Smart contracts create new possibilities and new risks. A bug in a contract can be exploited, and once funds are drained there is usually no one to appeal to. When a wallet asks you to "approve" a contract, you are giving it permission to move certain tokens, sometimes without limit. Grant approvals only to contracts you have good reason to trust, and review them from time to time.

Each network charges fees in its own coin. On Ethereum, fees are called gas and paid in ETH; they rise when the network is busy. On Tron, transactions consume bandwidth and energy, which can be obtained by staking TRX or paid for by burning TRX. In both cases, you need a little of the native coin in your wallet even if you only want to move a token like USDT.

What drives crypto value

Most crypto-assets produce no earnings, pay no interest by default and have no issuer promising to buy them back. Their price is whatever buyers and sellers agree at a given moment. Crypto value tends to be influenced by:

• Supply rules. Bitcoin's supply is capped at 21 million. Other assets may have ongoing issuance, token unlocks for early investors, or burning mechanisms that remove coins.
• Use and demand for block space. A network that people actually use to move stablecoins or run applications creates demand for its native coin to pay fees.
• Liquidity and interest rates. When money is cheap, speculative assets have tended to attract buyers; when rates rise, the reverse.
• Sentiment and leverage. Large leveraged positions can be forced shut in a falling market, pushing prices down faster.
• Regulation and security events. Enforcement actions, platform collapses and hacks can move the whole market.

Because none of these give a firm anchor, drawdowns can be deep. A simple piece of arithmetic shows why that matters: after a 40% fall, an asset must rise by 66.7% just to get back to where it started, because 0.6 × 1.667 ≈ 1.

Exchanges and how you buy

Most people first buy crypto on a centralised exchange: a company that verifies your identity, takes a bank transfer or card payment, and matches your order against other users in an order book. Many also offer a simpler "buy" button that quotes an all-in price with the spread built in. Decentralised exchanges, by contrast, let wallets swap tokens through smart contracts without an account, but you carry all the risk of mistakes and malicious contracts.

Expect identity checks. Regulated platforms must confirm who you are before you can deposit, and may ask where your money comes from. That can feel intrusive, but a platform that skips these checks entirely is also likely to be skipping other rules that protect customers. Withdrawals may also be delayed while a new account is reviewed.

Before using any platform, work through the checks in how to choose a broker or exchange, and read buying crypto with a debit card if you plan to pay by card.

How crypto works when you send coins

1. Check the network. Sending USDT on Tron to an address expecting Ethereum is a common and often permanent mistake.
2. Check the whole address, not just the first and last characters. Scammers create look-alike addresses and plant them in your history.
3. Send a small test first when using a new address.
4. Make sure you hold enough of the native coin, such as TRX or ETH, to pay the fee.

A sensible order of first steps

1. Read how the specific asset works, including who issued it and how new units are created.
2. Decide in advance the maximum you are prepared to lose, and treat that money as gone the moment it leaves your bank.
3. Check the platform using our ten-point checklist and note every fee on its schedule.
4. Turn on two-factor authentication using an authenticator app rather than text messages where possible.
5. Buy a small amount first and practise a withdrawal to a wallet you control.
6. Write your seed phrase on paper, store it offline, and never photograph it.

None of this makes crypto safe. It removes the avoidable mistakes, leaving only the risks you knowingly accepted.

The risks in one place

Tax is the other risk people forget. In many countries, swapping one crypto-asset for another, or spending it, can count as a disposal for tax purposes. Keep records of every purchase, sale and transfer. For a map of how crypto compares with regulated markets, see financial markets explained, and for the deeper mechanics of the original network, what Bitcoin is.

Sources

• Bitcoin protocol documentation
• Ethereum Foundation documentation on proof of stake
• UK Financial Conduct Authority, consumer warnings on crypto-assets