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.
xmrk ₿ ⚡️ /
npub1zu…2qhzy
2024-05-01 10:14:31
Author Public Key
npub1zues2p7qdajk9hv7xn5ldntj3pufzl3jwzwa4dhlavxdkj27g92q62qhzyPublished at
2024-05-01 10:14:31Event JSON
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"pubkey": "17330507c06f6562dd9e34e9f6cd728878917e32709ddab6ffeb0cdb495e4154",
"created_at": 1714558471,
"kind": 1,
"tags": [],
"content": "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.\nSo 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.\nEven worse, joinmarket spends together coinjoined coins. If they can be linked , it partially nullifies the previous coinjoin.\nPlease 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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}