Why People Say "Revoke" After a Crypto Wallet Hack

Whenever someone's crypto wallet gets drained, the replies are always the same: "Revoke everything!" Revoking token approvals is good advice, but it only helps in one kind of hack, and people often do it while missing the step that actually matters. This explains what an approval is, what revoking does and does not fix, and what to do first if your wallet is compromised.

This is a security explainer, not investment advice. Crypto trading is restricted for residents of Nepal by Nepal Rastra Bank.

Quick answer

An approval lets a smart contract move your tokens or NFTs without asking you again. Revoking cancels that permission. Revoke if you approved a contract that was hacked or turned out to be a scam. But if your seed phrase or private key was stolen, revoking is not enough: create a new wallet and move what is left immediately, because the attacker can sign anything you can.

Approve and Permit: what you are actually signing

• Approve is an on-chain transaction that lets another address, usually a smart contract, spend a set amount of a token from your wallet. Many apps ask for an unlimited amount so you do not have to approve again later.
• Permit does the same with an off-chain signature. It costs no gas, which is exactly why phishing sites love it: a single "sign this message" pop-up can hand over your tokens.
• setApprovalForAll is the NFT version. It gives a contract control over every NFT in a collection.

Approvals are normal. A marketplace needs one to move an NFT when it sells, and a DEX needs one to swap your tokens. The risk is that approvals stay active forever unless you remove them.

When revoking helps, and when it does not

Situation	Does revoking help?	What to do
A contract you approved was hacked	Yes	Revoke approvals to that contract right away.
You signed something on a phishing site	Yes, if it was an approval or permit	Revoke it, then check for other approvals you do not recognise.
Your seed phrase or private key was stolen	No	Make a new wallet and move remaining funds now. Treat the old one as burned.
Malware on your PC or phone	No	Clean or replace the device first, then set up a new wallet on a clean device.

How to check and revoke approvals

1. Open a trusted approval checker such as Revoke.cash, or the Token Approval Checker on Etherscan (or the explorer for your chain).
2. Connect your wallet or paste your address to view approvals. Viewing is free.
3. Sort by value at risk. Look for unlimited approvals, contracts you do not recognise, and old apps you no longer use.
4. Click Revoke on each one. Every revoke is an on-chain transaction, so you pay a small gas fee.
5. Repeat for each network you use (Ethereum, BNB Chain, Polygon, Arbitrum and so on), because approvals are per chain.

Type the checker's address yourself or use a bookmark. Fake "revoke" sites are a common trap for people who have just been hacked.

If your wallet is compromised: the order that matters

1. Work out how. Did you type your seed phrase into a site, sign an unknown message, or run a downloaded file?
2. If the seed or key leaked, create a new wallet on a clean device and move whatever is left, starting with the most valuable assets.
3. Revoke approvals on the old wallet if anything is still in it.
4. Check your devices for malware and change passwords for exchange and email accounts.
5. Do not trust anyone who DMs you offering to recover funds. Recovery scams target people right after a hack.

Habits that prevent this

• Approve only the amount you need, not unlimited, when the wallet lets you edit it.
• Read signature requests. If a site asks you to sign a Permit for tokens you were not trading, close it.
• Keep long-term holdings in a separate wallet, ideally a hardware wallet, that never connects to new sites.
• Review and revoke old approvals every few months.

Related reading: health factor in DeFi lending, why everything seems to be getting hacked, and how fake IT support scams work.

Frequently asked questions

What does revoke mean in crypto?

Revoking cancels a token approval you gave earlier, so the smart contract can no longer move your tokens or NFTs. It is an on-chain transaction and costs a small gas fee.

Should I revoke all approvals after a wallet hack?

Revoke approvals to anything suspicious, but first find out how the hack happened. If your seed phrase or private key was stolen, revoking does not help; move your remaining assets to a new wallet immediately.

Is it safe to use Revoke.cash?

It is widely used and lets you view approvals without signing anything. Always type the address yourself, because fake revoke sites target people who have just been hacked.

Does revoking cost money?

Yes, a small gas fee for each revoke transaction on that network. Checking your approvals is free.

What is the difference between approve and permit?

Approve is an on-chain transaction that grants spending permission. Permit grants the same permission with an off-chain signature, which costs no gas but is easier for phishing sites to abuse.