I would have them both fund the multisig simultaneously in the same transaction. A psbt would help with this. Alice and Bob both add a 10 btc input to the psbt and the psbt has one 20 btc output that goes into the multisig address. Then both review/cosign/broadcast it. That way neither party sends any money unless both do.
Discussion
Yes that’s perfect. So the multisig does not start until both have committed to paying. Once the exchange begins, neither can back out without losing everything.
Very cool. I have updated KNC to explain this in more detail. Seems like this would be relatively easy to build.
Awesome! Btw the GitHub description still says "Know No Customer (KNC) a bitVM Bitcoin exchange"
Consider changing that to something like "a bitcoin exchange based on multisig" or "based on incentives" or even "based on the game of chicken"
(I also like "based on mutually assured destruction")
Description has been changed. I like mutually assured destruction.
Okay, I have now contributed very little to this project haha.