What is cryptocurrency and how does it work?

Hi worlds

Cryptocurrency is money that exists only as records in a shared database. No bank holds the balance and no company can edit the history. Instead, thousands of computers keep the same copy of the same ledger and agree, continuously, on what it says.

That one design decision explains almost everything else about how crypto behaves — why transfers settle at any hour, why a lost password cannot be reset, and why prices move faster than most people expect.

The ledger, not the coin

It helps to stop picturing a coin. Bitcoin is not a file sitting in your wallet, and moving it does not send anything anywhere. What exists is a list of transactions. Your balance is simply the sum of the entries that point to your address.

This list is the blockchain. New transactions are grouped into a block, the block is added to the end of the chain, and every participant updates their copy. Each block carries a fingerprint of the one before it, so changing an old entry would break every block that followed it. Rewriting history is not forbidden by a rule — it is made expensive enough that nobody can afford it.

How a transaction actually moves

Sending crypto works through a pair of mathematically linked keys.

• Your public key produces the address you share to receive funds.
• Your private key signs outgoing transactions and proves the funds are yours.

When you send, your wallet signs the transaction with the private key and broadcasts it to the network. Other participants verify the signature, confirm the funds have not already been spent, and include the transaction in the next block. Once enough blocks have been added on top, the transfer is treated as final.

Nobody approves the transaction on your behalf. This is why the private key matters so much: it is not a password protecting an account someone else maintains, it is the ownership. Whoever holds it controls the funds, and there is no support line that can restore it.

Where the coins come from

Different networks issue new units differently, and the mechanism shapes how the network is secured.

Proof of work networks such as Bitcoin ask participants to spend computing power solving a problem with no shortcut. The first to solve it proposes the next block and receives newly issued coins. Attacking the chain would mean out-spending everyone else on electricity.

Proof of stake networks such as Ethereum ask participants to lock up coins as collateral instead. Validators are chosen to propose blocks and lose part of their stake if they misbehave. This consumes far less energy and is why Ethereum moved to it in 2022.

Most networks cap or taper issuance over time. Bitcoin will never exceed 21 million units, and the reward for producing a block halves roughly every four years.

What gives it a price

Nothing anchors a cryptocurrency to a national currency unless it is explicitly designed to track one. Price is what the most recent buyer and seller agreed on, and that number reacts to supply changes, regulation, network activity, and sentiment.

Stablecoins are the exception. Each unit is meant to hold a fixed value — usually one US dollar — backed by reserves or by an on-chain mechanism. They exist because a settlement layer is far more useful when the unit of account does not move while a trade is in progress.

Volatility is not a defect that will be engineered away. An asset with no central issuer and a fixed supply schedule has no mechanism to smooth demand, so the price absorbs all of it.

Custody: who holds the keys

There are two ways to hold crypto, and the difference is precise.

With self-custody, you hold the private keys yourself, in software or on a hardware device. You depend on nobody, and you carry the full consequence of losing the keys or the recovery phrase.

With custodial holdings, a platform holds the keys and credits your balance in its own records. You get password recovery and a familiar account model, and you take on the risk that the platform fails or restricts withdrawals.

Neither is universally correct. What matters is knowing which one you are using, because the two fail in completely different ways.

Before you buy anything

Three things are worth understanding first.

1. Transactions are final. A transfer sent to the wrong address cannot be reversed, and neither can one authorised by a scammer.
2. The network and the token are separate. Sending an asset over the wrong network is one of the most common ways funds are lost permanently.
3. Tax and reporting rules vary by country and usually apply to disposals, not just to withdrawals in national currency.

Cryptocurrency is a genuinely new settlement technology, and it is also a market where prices can fall sharply and stay down. Learning how the mechanism works is what turns it from a bet into a decision.