Re: [bitcoin-dev] CoinPool, exploring generic payment pools for Fun and Privacy

[ZmnSCPxj <ZmnSCPxj@protonmail.com>]

Good morning Antoine,


> Yes, that's part of future research, defining better *in-pool* observer. Sadly, right now, even if you use mask construction inside, it's quite easy to trace leaves by value weight. Of course, you can enforce equal-value leaves, as for a regular onchain CoinJoin. I think it comes with a higher onchain cost in case of pool breakage.


Perhaps not necessarily.

An advantage of WabiSabi is I can pretend to be two or more participants.

For example, I can pretend to be "Alice" and "Bob", and pretend that "Alice" owes a life debt to "Bob".

At initial state setup, I put a 1.0 BTC coin as "Alice" and a 0.5 BTC coin as "Bob".

Now, at each state update I need to sign as "Alice" and "Bob".
However, after the first initial state, I can use a new persona "Bobby" to *own* my coins, even though I still have to sign as "Alice" and "Bob" in every state update.

What the other pool participants see is that the 1.0 BTC "Alice" coin and the 0.5 BTC "Bob" coin are merged into the 1.5 BTC "Bobby" coin.
What they cannot be sure of is:

* "Alice" paid to "Bob", who is now pretending to be "Bobby".
* "Bob" paid to "Alice", who is now pretending to be "Bobby".
* "Alice" and "Bob" are the same person, and is also pretending to be "Bobby".

All the other participants know is that whoever owns the coin *now* is still part of the pool, but cannot be sure which participant *really* owns which coin, and whether participants are sockpuppets (which is why it should use n-of-n at each state update, incidentally).

In effect, it "imports" the possibility of PayJoin inside the CoinPool construction.



Regards,
ZmnSCPxj