e.g.
If Alice wants to pay bob, how can Alice convince Bob to use Payjoin?
First, payjoin gives alice an opportunity to have cheaper consolidation paid for by Alice, since the transaction already is proposed with her paying overhead.
Second, Alice can offer additional fees to pay for Alice's input, and by custom pays for 1 of Bob's input. There's no real cost to Alice to propose one, so it's an optimistic protocol that falls back to normal transaction behavior if Bob doesn't respond.
What does the final transaction look like in this simple case ?
If Alilce has 6 btc and wants to pay Bob 5, she'd always get her change as 1btc of output. But Bob could add his own input to augment his payment output, and get a transaction with inputs like {6, 2} and outputs {1,7}
e.g.
First, payjoin gives alice an opportunity to have cheaper consolidation paid for by Alice, since the transaction already is proposed with her paying overhead.
Second, Alice can offer additional fees to pay for Alice's input, and by custom pays for 1 of Bob's input. There's no real cost to Alice to propose one, so it's an optimistic protocol that falls back to normal transaction behavior if Bob doesn't respond.
If Alilce has 6 btc and wants to pay Bob 5, she'd always get her change as 1btc of output. But Bob could add his own input to augment his payment output, and get a transaction with inputs like {6, 2} and outputs {1,7}