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xmrk ₿ ⚡️ /
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2024-05-01 10:14:31

xmrk ₿ ⚡️ on Nostr: Joinmarket has a big flaw: it happily spends all your funds in a particular mixdepth ...

Joinmarket has a big flaw: it happily spends all your funds in a particular mixdepth when doing coinjoin as maker. This can reveal common ownership . An analyst can try all combination of inputs and try to match "change" outputs. Say there are several 1M sats outputs - analyst cannot link them to particular input(s). But if you contributed with 800k and 400k inputs, then you'll get a 200k change output. So if there is no other way to combine inputs to get 1.2M sats, then those 800k and 400k inputs are linked.
So if one input comes from Bisq purchase and another input comes from closing a channel of my node, then Bisq seller can deduce that I am the owner of one of the participating lighting nodes.
Even worse, joinmarket spends together coinjoined coins. If they can be linked , it partially nullifies the previous coinjoin.
Please tell me I misunderstood something. I vaguely remember that it sometimes creates 3 outputs (only for a taker perhaps?), this could save the day.
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