Track 2 · Keys & identity · lesson 7
Connecting a wallet is not handing over your key
6 min
"Connect wallet" is the most misunderstood button in crypto. People treat it like handing over their keys. It is closer to telling someone your name.
Connecting shares one thing: your address.
The site learns which account you are using and can read your public on-chain history — which is public anyway. It gains no ability to move anything.
Your private key never leaves the wallet. Not on connect, not on signing, not ever. The wallet signs on your behalf and returns only the signature.
What a connected site can and cannot do
Can:
- See your address, and everything public associated with it.
- Ask you to sign a message.
- Ask you to send a transaction.
Cannot:
- Read your private key or seed phrase.
- Move funds without a prompt you approve.
- Do anything at all while you are not looking.
Every action is a request. You are the one who approves it.
Predict
If connecting is safe, why do people still lose funds to malicious sites?
Where the real danger lives: approvals
To let a contract move your tokens, you grant an approval. Most interfaces request an unlimited one, so you never have to approve again.
That approval persists after you disconnect, after you close the tab, and after you forget the site existed. If the contract is malicious — or is compromised later — it can drain that token whenever it likes.
Disconnecting does nothing to revoke it. Disconnecting is a UI state; the approval is on-chain.
Two habits worth having from today:
- Review your approvals periodically and revoke ones you no longer use. Revoke.cash and Etherscan's token approval checker both do this.
- Use a burner wallet for anything experimental. A separate address with a little ETH cannot lose what it does not hold.
You will exploit an unlimited approval yourself in track 7, which is a considerably more memorable way to internalise this than being told.
Check
You disconnect a site in MetaMask. What happens to the token approval you granted it?
Worth remembering
- Connecting a wallet shares your address and nothing else — the private key never leaves.
- A connected site can only ask; every action needs your approval.
- The risk is not the connect, it is the prompt that follows.
- Token approvals persist on-chain after disconnecting and must be revoked explicitly.
- Review approvals periodically, and use a burner wallet for anything experimental.