What is the consensus on how to make instant transactions work in bitcoin while of course avoiding double spending. I've heard of various things like green address.
But consider implementing some generic game on a website that involves betting with bitcoin. How would you make instant transactions work given the following constraints.
- No deposits
The website must not hold deposits of bitcoins. Maintaining deposits is a security annoyance. Bets are instead placed through transactions from a bitcoin wallet that is under full control of the player. When a player wins the bitcoins that were being temporarily held by the server are sent to the winner. And the game continues on. Therefore response needs to be fast and the transactions must be instant.
- Minimize having to refund because one player backs out of bet
A bet involves two players and before the game continues both players must send their bet of bitcoins. If one player sends their bet but the other leaves the game, then the first player must be refunded their bitcoins. However this means that those refunded bitcoins are useless until the refund transaction is confirmed by the bitcoin network (could take tens of minutes?). In a fast paced game this decrease in effective usable bitcoins could be unacceptable. I would like to avoid the effects of these annoying leavers.