Just a quick question on blockchain interoperability that REN attests to be able to handle.

If person A wants to use a smart contract on REN such that person B is only paid when a condition is achieved, which address does he send the BTC in order for REN to convert them into a BTC-equivalent on the ETH chain, and who controls that wallet? Is it to a special BTC multi-sig wallet where only a set of darknodes must collaborate to decipher the private key?