Do you know what a Payjoin is? Here's what I learned from nostr:npub170d8w0jjdcjuh70lq5ppr0pcy7cfuxj6hpr00tm4et3v53j8pvrqj0chu7 :
Payjoin is a variation of CoinJoin, wherein the sender collaborates with the transaction recipient to conduct a joint transaction. Originating from BIP-78, crafted by nostr:npub1zfytz6ktce3av2svlfpl0e79e44tnskxmvlpkcmc7q0xct3qa49swvm60l (the creator of nostr:npub155m2k8ml8sqn8w4dhh689vdv0t2twa8dgvkpnzfggxf4wfughjsq2cdcvg ), it addresses a key problem in typical transactions where a sender pays a merchant. This problem is the 'common-input ownership' heuristic. Simply put, when I send you money, all the inputs are usually mine.
Moreover, transaction outputs often reveal the recipient and change due to differences in address types (change-scriptpubkey) and the presence of rounded, larger, or smaller amounts (change-round-amount).
Payjoin mitigates these issues:
For the recipient, it provides a chance to consolidate their coins. They can even make payments in the same transaction where they receive a payment.
For the sender, it alleviates privacy concerns related to the mentioned heuristics.
Payjoin is becoming popular across several implementations.
I did a search and looks like since 2020 this was in the works:
https://twitter.com/HillebrandMax/status/1253682677774983170
Hey nostr:npub167hmfzj38hkumks4wxny89797la0sf7wnwfrw4enlmcl82msp0cs78schc - I'm not sure if this is really your npub - I tried to use find it in https://wasabiwallet.io/ and could not see a Nostr link and https://www.nostr.directory/p/wasabiwallet told me user is not found.
Anyway, special thanks and praise to nostr:npub1mutnyacc9uc4t5mmxvpprwsauj5p2qxq95v4a9j0jxl8wnkfvuyque23vg for their Nostr-First approach and recently posting about Payjoin. This is how I heard about it today.
(This is my contribution to help spreading around the concept of Payjoin and apologies if something got lost in translation. In case anyone zaps this note, I will be splitting it with nostr:npub170d8w0jjdcjuh70lq5ppr0pcy7cfuxj6hpr00tm4et3v53j8pvrqj0chu7 who was kind to teach me in simple language about what this Payjoin is about)