How to revoke smart contract permissions in Trust Wallet?

Understanding Smart Contract Permissions in Trust Wallet

When using Trust Wallet to interact with decentralized applications (dApps) on blockchains like Ethereum, Binance Smart Chain, or Polygon, you may need to grant smart contract permissions. These permissions typically allow a contract to spend specific tokens from your wallet, such as approving a decentralized exchange (DEX) to swap your ERC-20 tokens. Once approved, the contract has access until you manually revoke it. This access can pose a security risk if the dApp is no longer trusted or compromised. Understanding how these permissions work is essential to maintaining control over your digital assets.

Smart contract approvals are blockchain transactions recorded permanently. They do not expire automatically. The approval process involves signing a transaction that sets an allowance for a specific contract address to transfer your tokens. This allowance can be limited to a certain amount or set to an unlimited value. Regardless of the amount, if you no longer use the service, it's safer to revoke these permissions.

Why Revoke Smart Contract Permissions?

Leaving active smart contract permissions increases your exposure to potential exploits. If a dApp you approved suffers a security breach, attackers could use your existing approval to drain your tokens. Even if the dApp is legitimate now, future updates might introduce vulnerabilities. Revoking unused permissions reduces your attack surface.

Another reason to revoke is privacy and control. You may have granted access during testing or a one-time transaction. Keeping those approvals active serves no purpose and contradicts the principle of least privilege in security. By revoking, you ensure that only currently needed contracts have access to your funds.

It's also important to note that unlimited allowances are especially risky. A contract with unlimited access can withdraw your entire token balance at any time. Revoke these first if they are no longer needed.

How to Check Active Smart Contract Approvals

Before revoking, you must identify which contracts have active permissions. Trust Wallet does not display this information directly in its interface, so you'll need to use external tools.

• Visit revoke.cash, a trusted open-source platform for managing token approvals.
• Connect your Trust Wallet by selecting 'WalletConnect' and scanning the QR code from the browser interface.
• Once connected, the site will display all active token approvals associated with your wallet address.
• Review the list to see which contracts have spending rights over your tokens.
• Each entry shows the token name, contract address, and allowance amount. Unlimited allowances will be clearly marked.

Alternatively, you can use Etherscan (for Ethereum) or BscScan (for Binance Smart Chain). Navigate to your wallet address, go to the 'Token Approvals' or 'Proxied Contracts' section, and inspect the transactions under 'Internal Txns' or 'Token Approvals' tabs. These platforms allow you to see past approval transactions.

Revoking Permissions Using Revoke.cash

Revoke.cash is the most user-friendly method to revoke smart contract permissions from your Trust Wallet.

• Go to revoke.cash and connect your wallet via WalletConnect.
• After connection, the dashboard will load all active approvals.
• Locate the contract you want to revoke. You can filter by token or contract address.
• Click the 'Revoke' button next to the approval.
• A transaction window will appear in Trust Wallet. Confirm the transaction.
• The transaction will be sent to the blockchain. You can track its status via the blockchain explorer.
• Once confirmed, the contract will no longer have spending rights over that token.

If you have multiple approvals, you can revoke them one by one. Some users choose to revoke all unused permissions at once for maximum security. Each revocation requires a small gas fee, paid in the native token of the network (e.g., ETH for Ethereum, BNB for BSC).

Manual Revocation via Contract Interaction

If you prefer not to use third-party tools, you can manually revoke permissions by interacting with the token contract directly.

• Open Trust Wallet and go to the DApp browser.
• Navigate to Etherscan.io or BscScan.com, depending on the network.
• Search for the token contract address you want to revoke.
• On the contract page, go to the 'Contract' tab and find the 'Write Contract' section.
• Connect your wallet using Web3.
• Locate the 'approve' function in the list.
• In the 'spender' field, enter the contract address you wish to revoke.
• In the 'value' field, enter 0 to remove the allowance.
• Click 'Write' and confirm the transaction in Trust Wallet.
• Wait for the transaction to be confirmed on-chain.

This method requires more technical understanding but gives you full control without relying on external interfaces.

Best Practices for Managing Smart Contract Permissions

Always review the contract address before granting or revoking permissions. Scammers may create fake dApps with similar names. Verify the official website and contract address through trusted sources like the project’s GitHub or community announcements.

Limit token allowances whenever possible. Instead of approving an unlimited amount, specify the exact amount needed for the transaction. Many dApps support this option during the approval step.

Regularly audit your active approvals. Make it a habit to check every few weeks using revoke.cash. Remove any permissions for services you no longer use.

Avoid interacting with unknown dApps. Only approve contracts from reputable platforms. If a site asks for approval without clear reason, it may be malicious.

Frequently Asked Questions

Does revoking a smart contract approval cost gas?Yes, revoking an approval is a blockchain transaction that requires a gas fee. The fee is paid in the native token of the network (e.g., ETH, BNB) and varies based on network congestion.

Can I revoke permissions for multiple contracts at once?Currently, each revocation must be done individually. There is no batch revoke function on revoke.cash or directly in Trust Wallet. Each transaction must be confirmed separately.

What happens if I revoke a contract I still use?If you revoke a contract that a dApp requires, the dApp will no longer be able to access your tokens. You will need to re-approve the contract to use the service again. This is safe but adds an extra step.

Is revoke.cash safe to use with Trust Wallet?Yes, revoke.cash is an open-source, non-custodial tool. It does not have access to your funds. It only facilitates transactions that you approve in your wallet. Always verify the URL to avoid phishing sites.