Wallets and Private Keys

Your wallet is your bank account and your ID

In Web2, you log into websites with an email and password. In Web3, you connect with a wallet. Your wallet does three things:

Holds your money — your ETH, tokens, and NFTs
Proves your identity — your wallet address is your on-chain identity
Signs transactions — confirms that you approve a transfer or contract interaction

There is no company behind your wallet. No bank holds your funds. You hold them directly.

Public keys and private keys

Every wallet is built on a pair of keys.

Private key → a secret number (like a password you can never change). If someone gets it, they control your money.

Public address → derived from the private key using math. You share this with anyone who wants to send you crypto. It starts with 0x on Ethereum.

The key point: you can go from private key → public address, but you cannot go backwards. Nobody can figure out your private key from your public address.

The seed phrase

Managing a raw 256-bit private key is impractical. That is why wallets use a seed phrase (also called a recovery phrase): 12 or 24 English words that encode your private key.

Example seed phrase (do NOT use this — it is just for illustration):

apple banana cherry dragon eagle frost grape hollow ivory jewel kite lemon

From these 12 words, your wallet can generate your private key, your public address, and even multiple accounts. If your phone breaks, you install a new wallet app, enter the 12 words, and everything is restored.

The rule: Write your seed phrase on paper. Store it somewhere safe. Never type it into a website. Never screenshot it. Never email it. If someone asks for your seed phrase, it is a scam. No exception.

Types of wallets

Hot wallets are connected to the internet. Easy to use but more vulnerable to hacks. Use them like a wallet in your pocket — carry spending money, not your life savings.

Cold wallets keep your keys offline. A hardware wallet like Ledger is a USB-sized device that stores your private key on a secure chip. When you want to sign a transaction, you physically press a button on the device. Even if your computer has malware, the hacker cannot access your keys.

How to stay safe

Do	Do not
Write seed phrase on paper	Screenshot your seed phrase
Store backup in a safe	Keep it in a notes app or cloud
Use hardware wallet for savings	Keep large amounts in a browser wallet
Double-check addresses before sending	Rush transactions
Start with small test transactions	Send large amounts to unverified addresses
Bookmark the real website URLs	Click links from DMs or emails

Common scams to watch for:

"Connect your wallet to claim free tokens" — this is almost always a scam. The website drains your wallet when you approve the transaction.

"Send me your seed phrase to verify your wallet" — no legitimate service will ever ask for your seed phrase. Ever.

"This token will 100x" — unsolicited investment advice in DMs is a scam. Always.

Key takeaways

Your wallet has a private key (secret, controls your funds) and a public address (shareable, receives funds).
A seed phrase is 12 or 24 words that can restore your entire wallet. Guard it like cash.
Hot wallets (MetaMask, Phantom) are for daily use. Cold wallets (Ledger, Trezor) are for savings.
If you lose your seed phrase and your device, your crypto is gone. There is no password reset.