How do i revoke an ERC20 or ERC721 token approval given to a smart contract

Question

I've granted allowance to a smart contract to spend some tokens on my behalf, but it seems i gave it unlimited access.

I want to revoke this access as i now know that this could be a potential opening for an attack on my address(wallet).

I noticed that block explorers like etherscan or wallets like coinbase have a tool that makes revoking approvals possible.

I'm interested in knowing how this would work, and how i can build something similar. I dont think this is a feature that ERC20 OR ERC721 tokens currently support natively.

Thanks.

Answer 1

You just need to call the contract's function setApproval(ERC721) or setApprovalForAll(ERC1155 & ERC721) and pass false as the bool value

EDIT - added ERC20 standard

//for ERC1155 & ERC721
function setApprovalForAll(address operator, bool approved)

//only for ERC721
function approve(address to, uint256 tokenId)

//for ERC20 according to the EIP-20
function approve(address _spender, uint256 _value) public returns (bool success)