Sending hash in function parameter

Question

I'm writing a smart contract where the user sends a hashed string : the answer of an asked question (because I don"t want it to be public in the blockchain). It is compared to the correct hashed answer:

function answerQuestion(bytes32 _answer) notAnswered returns (string){
    if(_answer == keccak256(answer)){
        isAnswered = true;
        winner = msg.sender;
        return pos;
    }
    return "WRONG";
}

It gives me something like 57315cf71be5ffcaf957b9cc196b322e1c4d5a1832396abcee71d05d8caf41a6 and I parse it as the parameter in the browser solidity. But it returns:

Error encoding arguments: SyntaxError: Unexpected token c in JSON at position 6

Any idea how should I fix this?

Answer 1

I am developing a smart contract using the Remix IDE and I ran into the same issue. I solved this issue by appending 0x to the beginning of the hash.

0x57315cf71be5ffcaf957b9cc196b322e1c4d5a1832396abcee71d05d8caf41a6