Wallets & Private Keys

A wallet is a keychain, not a bank account

A crypto wallet doesn't actually store your tokens — the blockchain does. What your wallet stores is a private key: a secret number that lets you sign transactions proving ownership of an address. The wallet app (like MetaMask) is really a keychain plus a signer plus a friendly interface on top.

Keys and addresses

Private key — a secret you never share. Anyone who has it fully controls the wallet.
Public address — derived from the private key, this is what you share to receive funds (e.g. 0x71C7...976F).
Seed phrase — usually 12 or 24 words that can regenerate every private key in a wallet. Losing it, or exposing it, is equivalent to losing or exposing your funds.

Key idea "Not your keys, not your coins." If a private key lives on someone else's server (like an exchange), you're trusting them, not the blockchain, to protect your funds.

How wallet login works

Sites like this one don't ask for a username and password. Instead, the page asks your browser's wallet extension for permission to see your address — that's the Connect Wallet button above. Under the hood it calls a standard interface every EVM wallet implements, called EIP-1193, and requests the accounts you approve to share. The site never sees your private key; it only ever sees the public address you've agreed to reveal.

Custodial vs. non-custodial

A non-custodial wallet (MetaMask, Rabby, a hardware wallet) means you alone hold the private key. A custodial wallet (most exchange accounts) means a company holds it on your behalf. DeFi apps are built to work with non-custodial wallets, since the whole point is removing the middleman.