Date: Mon, 25 May 2020 06:54:27 +0000
To: "prayank@tutanota.de" <prayank@tutanota.de>,
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
From: ZmnSCPxj <ZmnSCPxj@protonmail.com>
Reply-To: ZmnSCPxj <ZmnSCPxj@protonmail.com>
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Subject: Re: [bitcoin-dev] Post-mix(coinjoin) usage with multisig and cpfp
	in bitcoin core wallet
Precedence: list

Good morning Prayank

> I have explained the whole idea with a proof of concept in this link:=
=C2=A0https://medium.com/@prayankgahlot/post-mix-usage-using-multisig-and-c=
pfp-e6ce1fdd57a1

The article is not clear I think, so please confirm my understanding below.

Participants:

* "Peer 3" - Payee
* "Peer 2" - Payer
* "Peer 1" - Enabling tr\*sted third party

Goal: Payer wants to pay to the payee 0.006BTC

Current Conditions:

* Payer owns 0.01 BTC in a single UTXO
* Third Party owns 0.05 BTC in a single UTXO

Protocol:

1.  Payer and Third Party compute a 2-of-3 address with the public keys of =
Payer, Payee, and Third Party.
2.  Payer and Third Party individually pay their owned funds to the 2-of-3 =
address.
3.  After confirmation, they consume the new outputs into another transacti=
on with equal-valued outputs, hiding who owns which coins.

Is my understanding correct?

If so, I believe JoinMarket has a superior technology, which does not requi=
re a tr\*sted third party; it simply requires one or more UNtrusted third p=
arties to participate in signing a single transaction that does not require=
 paying to an intermediate m-of-n address (thus all inputs are singlesig).

Basically JoinMarket allows the market taker to decide how much the equal-v=
alue outputs are, and to define the address it goes to.
The destination address need not be one the market taker controls, it can b=
e to a payee.
This technique is the only out-of-the-box way that a JoinMarket wallet can =
spend funds from a JoinMarket wallet.

JoinMarket as well already includes how to get in touch with enabling third=
 parties (called "market makers").


Regards,
ZmnSCPxj