Your first crypto wallet: keys, seed phrases and staying safe

Every crypto wallet, from a phone app to a hardware device, does the same job: it keeps the keys that let you move your coins. The coins themselves never leave the blockchain. Once that idea clicks, the rest of this lesson follows from it.

What a wallet actually holds

A wallet holds a pair of keys:

• A private key, a secret number that signs your transactions. Whoever has it controls the funds.
• A public address, worked out from that key, which you share so people can send you crypto.

Think of the address as your mailbox number and the private key as the only key to the mailbox. You can hand out the number freely; you never hand out the key.

Not your keys, not your coins. If someone else holds the private key, they decide what happens to the funds, not you.

Custodial or self-custody?

Plenty of people use both: an exchange to buy, and a self-custody wallet to hold.

Your seed phrase is the master key

When you create a self-custody wallet, it shows you a seed phrase (also called a recovery phrase): usually 12 or 24 ordinary words. Those words can recreate every key in the wallet on any device.

• Write it on paper, in order, and keep it somewhere safe and private. Some people use a steel backup plate.
• Never type it into a website, a form or a chat, and never photograph it or save it to the cloud.
• Nobody legitimate will ever ask for it: not support staff, not a wallet app, not CryptoMondays. Anyone who asks is trying to take your funds.

Your first address

Once your wallet is set up, copy its public address:

• An Ethereum address starts with 0x, followed by 40 letters and numbers, for example 0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed.
• A Solana address is 32 to 44 letters and numbers, with no 0x in front.

You can add these addresses to your Learn profile so the organisers can send you rewards. Only ever paste the public address. A site that asks for your seed phrase to "connect" your wallet is a scam.

Five habits that keep you safe

1. Send a small test first. Before moving a large amount, send a little and confirm it arrived.
2. Check every address. Compare the first and last few characters before you send; some malware swaps addresses on your clipboard.
3. Type important sites yourself, or use a bookmark, rather than following links from messages or adverts.
4. Be wary of direct messages. Unexpected offers, "support" accounts and urgent warnings are the most common scams.
5. Consider a hardware wallet once you hold more than you would be comfortable losing. It keeps your keys off your computer.

Try it

• Install a well-reviewed wallet app from its official website or your phone's app store.
• Write your seed phrase down on paper and store it safely.
• Copy your public address and add it to your Learn profile.
• Send yourself a tiny test amount, or ask how at the next meetup.

This lesson is education, not financial advice. Never put in more than you can afford to lose.