I think my confusion stems from my use case: where Alice and Bob are the same person (2-party with only Alice & Carol) who will calculate the X Value?
Alice does, and it's perfectly fine that alice knows it first. It might help you to try to describe the attack you're feeling might be there in concrete terms.I'm looking at the point where Alice generates X & HX, Alice sends Carol HX. They both then create, sign & exchange TX_2 & TX_3 transactions that spend TX_0 & TX_1 with the common hash lock.
It seems that whomever holds X has an advantage here.
What is to stop Alice from simply not sending Carol X (so Carol can't spend TX_2) announcing TX_3 which spends TX_1, and then announcing the TX_0_Refund as well?
I am sure I am missing something here, I appreciate your patience
