Smart Contract Execution Rights - Can everyone who knows the public address of a smart contract call the smart contract?

Question

Say I have a contract with the address and method below.

myContract.at("0x9f8cedf1f93e46fac74cb9415db8bbec85f239b4").greet();

Can everyone who knows this address call this smart contract method? Any permissions restrictions?

Answer 1

It depends how you write the contract.

You get the access control you design. There are more intricate access control patterns such as whitelists, but to lay out a simple example that is admittedly flawed, but hopefully illustrative:

  contract Greeter {

  address public owner; 

  function Greeter() public {
    owner = msg.sender; // <= the "owner" will be set to the account that deployed it. 
  }

  function greet() public view returns(string greeting) {
    require(msg.sender == owner); // only the priviledged account will pass
    return "Hello, owner.";
  }
}

Hope it helps.