How to check if Ethereum address is valid in solidity?

Question

Is there a way to check if the ethereum address is valid in solidity? I think I might have found a way in web3js library on utils, but want to know if this method is possible on solidity.

And how can I use solidity to know the difference between account addresses and smart contract address?

The EVM will check and fail if any value set to an address function argument is not an address. You can also use tests like `require(anAddress == address(anAddress),"Invalid address");` — Emmanuel Collin, Aug 31 '20 at 08:11
What do you mean by a valid address? About the contract addresses you can read there https://stackoverflow.com/q/37644395/7450049 — Vitaly Migunov, Aug 31 '20 at 13:19

score 2 · Answer 1 · answered Aug 12 '22 at 14:21

And how can I use solidity to know the difference between account addresses and smart contract address ?

You can use EXTCODESIZE opcode.

function isContract(address _a) public returns (bool) {
  uint size;
  assembly {
    size := extcodesize(_a)
  }
  return size > 0
}

How to check if Ethereum address is valid in solidity?

1 Answers1