You have probably heard that a blockchain is a new kind of database. That is true, but it misses what makes it interesting: nobody owns it, anyone can check it, and once something is written it is very hard to change. This guide explains the idea in plain language, without maths.
A shared ledger anyone can check#
Picture a notebook that records every payment between people. In a bank, one company keeps that notebook and you trust it to be honest. A blockchain gives a copy of the notebook to thousands of computers around the world. When someone sends a payment, every copy is updated in the same way, so anyone can check the record for themselves.
| Traditional ledger | Public blockchain | |
|---|---|---|
| Who keeps it | One company | Many independent computers |
| Who can read it | The company and you | Anyone |
| Changing history | Possible for the company | Extremely hard for anyone |
| Opening hours | Business days | Always on |
Blocks, hashes and the chain#
Transactions are grouped into batches called blocks. Each block gets a unique fingerprint, called a hash, that is calculated from everything inside it. Change one character and the fingerprint changes completely.
Every new block also stores the fingerprint of the block before it. That link is the “chain”. To rewrite an old payment you would have to rebuild every block after it, on most of the computers in the network, at the same time. In practice that is not realistic.
- A transaction is signed and sent to the network.
- Computers check that it follows the rules.
- It is added to a new block that points to the previous one.
- Every copy of the ledger adds the same block.
Who keeps the ledger#
The computers that store and check the ledger are called nodes. Some nodes, often called validators, also propose and vote on new blocks. They are run by independent people and organisations, which is why no single party can quietly edit the record.
A blockchain replaces “trust the record keeper” with “check the record yourself”.
Agreeing on the truth#
With thousands of copies, the network needs a way to agree on which block comes next. This process is called consensus. Older networks use proof of work, where computers compete to solve a puzzle. Solana uses proof of stake, where validators lock up SOL as a promise of good behaviour and risk losing rewards if they cheat. Proof of stake uses far less energy and lets the network confirm payments in seconds.
Keys, addresses and wallets#
Your coins never leave the blockchain. What a wallet holds is a pair of keys. The public address is like an account number you can share to receive funds. The private key signs your transactions and proves that you own the address. Your recovery phrase is a human-readable backup of that private key.
SOLKEEP keeps your keys on your device and asks you to approve every transaction. Read more in the wallet FAQ.
Where to go next#
- Open your SOLKEEP world and create or restore a wallet.
- Learn how to send money on a future date with scheduled payments.
- Turn your wallet into a shareable 3D scene with Solkeep Studio.
Frequently asked questions
Is a blockchain the same as a cryptocurrency?
No. A blockchain is the shared record. A cryptocurrency such as SOL is an asset tracked on that record. One blockchain can track many different tokens.
Who controls a public blockchain?
No single company. Thousands of independent computers keep copies of the ledger and follow the same rules to agree on which transactions are valid.
Can a blockchain transaction be reversed?
Generally no. Once a transaction is confirmed it becomes part of the shared history. Always check the address and amount before you approve a payment.
Is everything on a blockchain public?
On public blockchains like Solana, addresses, balances and transactions are visible to anyone. Your name is not stored, but addresses can sometimes be linked to people.
Do I need to understand blockchains to use a wallet?
Not in depth. It helps to know that your recovery phrase is the key to your funds, that transactions are hard to undo and that fees are shown before you approve.
