9

In a smart contract, if we make a member variable public:

Question 1: Can a malicious party write a transaction/contract and change the value/state of the public variable in the contract?

Question 2: Would the problem be solved by only turning public to private?

For instance, if in a contract we have:

address private owner;

and in the contract constructor we have:

 owner= msg.sender;

then we have a getter function like:

get_owner() returns (address){
  return ownner;

}

then nobody can change owner, but if have

address public owner;

someone may change it later on?


But if we have a getter function as above, MyEtherWallet (to interact with a contract on testrpc) does not read/return owner, unless we turn public owner to a private one.

Question 3: Why MyEtherWallet does not return a value, for the getter functions that we write?

16
  1. No. For public variables with a global scope within a contract, only getters for those variables are automatically created by the compiler, not setters.
  2. Because of the first answer, this does not apply.
  3. About MyEtherWallet I can't understand the issue, but it should be able to automatically show all public functions of the contract (getters included), like other tools do (i.e. remix). Please note that usually a ÐApp expose functions reading the ABI of the contract. The ABI in any case is always provided by the user (for some famous contract MEW can suggest to the user a known ABI)

You can find more useful information about variables and functions visibility in the official documentation.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.