How does cryptocurrency work?
Follow one payment from your wallet to the blockchain, and see what each part of the system does.
You sign a transaction with your private key. Your wallet broadcasts it to the network, computers check the signature and that you have the funds, and it's bundled into a block. Once the block is added to the blockchain, the payment is confirmed and very hard to undo.
One payment, step by step
- You create the payment. In your wallet you enter the receiver's address and the amount. The wallet adds a network fee.
- You sign it. Your wallet uses your private key to make a digital signature. The key itself never leaves your wallet; only the signature is shared.
- It's broadcast. The signed transaction goes out to computers on the network (nodes). It waits in a queue of unconfirmed transactions, often called the mempool.
- It's checked. Every node checks the signature is valid and that the coins haven't already been spent. Invalid transactions are dropped.
- It's put in a block. A miner (proof of work) or validator (proof of stake) bundles waiting transactions into a block, usually picking the ones paying higher fees first.
- The block is added. The network agrees on the new block and adds it to the chain. Your payment now has one confirmation.
- Confirmations build up. Each new block on top makes it harder to reverse. Many services wait for several confirmations before treating a large payment as final.
The parts that make it work
| Part | What it does | Everyday comparison |
|---|---|---|
| Blockchain | The shared record of every transaction | A ledger book that everyone has an identical copy of |
| Nodes | Computers that keep a copy and check the rules | Thousands of independent auditors |
| Private key | Proves you own the coins and authorizes spending | Your signature plus the key to the safe, in one |
| Address | Where coins are sent; safe to share | Your account number |
| Miners or validators | Add new blocks and earn fees and new coins | Clerks who write the next page of the ledger |
| Consensus rules | How everyone agrees which blocks count | The rulebook everyone follows |
How long does it take?
It depends on the network and how busy it is. Bitcoin adds a block about every 10 minutes on average. Ethereum adds one every 12 seconds. Many other networks are faster. Paying a higher fee usually gets you into a block sooner when the network is busy.
Why payments can't be reversed
There's no bank to call. Once a transaction is buried under enough blocks, reversing it would mean redoing all that work (or controlling a huge share of the staked coins), which is practically impossible on large networks. That's what makes crypto hard to censor, and also what makes mistakes and scams so costly.
Always send a small test amount first when moving a large sum to a new address, and double-check that the address and network match on both sides.
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Frequently asked questions
What is a confirmation?
A confirmation means your transaction is in a block on the chain. Each later block adds another confirmation. More confirmations mean it's more firmly settled.
Why is my transaction pending?
It's waiting to be included in a block. That usually happens when the network is busy and the fee you paid is lower than others are paying. Many wallets let you speed it up by paying more.
Do I need the internet to use crypto?
To send a transaction, yes, something has to broadcast it. But keys can be stored offline in a hardware wallet, and transactions can be signed offline and broadcast later.
Where to next
Sources
Written for beginners and checked against the sources listed. Last reviewed October 26, 2026. This page is educational and is not financial, tax or legal advice. How we write and check pages.