smart contact to release funds with a random password?

Question

I'm interested in building an app that would generate a new smart contract every time two users of my app come to an agreement:

The first user would then send eth to the smart contract, and would receive a simple passphrase (something like a pin code) in return. the second user would provide an eth address to receive the funds.

Then, sending the passphrase to the smart contract would allow for the release of the funds.

It would also be great if the funds are actually sent back to user1 after a certain period if the passphrase hasn't been entered.

Does that sound easy to do? I assume this is exactly the sort of stuff one can do with ethereum, right? I'm pretty new with these sort of things, would there be an example I could use as a base? Thanks a lot in advance!

Answer 1

Can be done, and the contract can do other things if needed since it's the trusted man-in-the-middle overseeing this. You probably want to remove the passphrase from the process because there are generally better solutions.

I removed the password bit entirely. It's not clear to me at this what purpose it would serve. I would need to know what's for to work out the Ethereum way to doing it.

In the example, sender sends the funds. The contract doesn't wait for anything before pushing funds through to receiver. Not possible anyone else got paid.

Just a minimal example:

contract Forward {

  event LogFundsForwarded(address from, address to, uint amount);

  function forwardFunds(address receiver) 
    payable 
    public
    returns(bool success)
  {
    if(msg.value==0) throw;
    if(!receiver.send(msg.value)) throw;
    LogFundsForwarded(msg.sender, receiver, msg.value);
    return true;
  }

}

Hope it helps.