Just deploy a smart contract on, say, Ethereum MainNet. One side will publish the public keys for RSA and the private key signature can take the money. The ot

Just deploy a smart contract on, say, Ethereum MainNet. One side will publish the public keys for RSA and the private key signature can take the money. The other side will likewise lock up some money, but that money can be moved by a smart contract method after a certain date, if the first account still has money in it. You can have multiple dates, for removing some or all of the money in the multiple bets against it. For example, "$200 that it's cracked by 2004". The main problem with bets and contests is that the side which knows the private key can simply withdraw the money itself. That’s why you need the private key to be generated by all parties involved in a ceremony.