Lesson 2 of 4 · 4 min read
Wallets & keys
Not your keys, not your coins. What does that mean?
Public & private key
Your public key is like your account number (anyone can see it). Your private key is your password — whoever has it owns the crypto.
Hot vs cold wallet
Hot wallet = online, convenient but vulnerable. Cold wallet = offline hardware, safer for large amounts.
Seed phrase
12-24 words that let you restore your wallet. Write them down on paper, NEVER share them. Whoever has your seed phrase has everything.
'Not your keys, not your coins'
If you leave your crypto on an exchange, then technically the exchange owns the keys — not you. If that exchange goes bankrupt or gets hacked, you may lose your money. Only in your own wallet do you have real control.
FTX collapses: billions in customer funds vanished
Users who left their crypto on the exchange FTX suddenly couldn't access it overnight. 'Not your keys, not your coins' was proven in the harshest possible way.
Remember this
- Public key = your account number (fine to share); private key = your password (never share).
- A cold (offline) wallet is safer for large amounts than a hot (online) wallet.
- Your seed phrase restores your entire wallet — keep it offline and never share it.
- Crypto on an exchange = the exchange owns the keys; only your own wallet gives you control.
There is a quiz for this lesson
3 questions that check whether it stuck. They live in the app, because a quiz nobody grades teaches nothing.
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