There has got to be a way to mathematically lauder crypto. I know we are talking about highly illegal math. I will take my chances.

I wonder if like a "network" that has nodes whose only job is to launder money. Their traffic and exchanges of value are all mish-mashed up like Tor, but meanwhile trying to conserve on "gas", so we're always talking about "chunks" of value that are big enough to mitigate that to everyone's satisfaction.

Consider a single node...

It has a number of wallets for the various things it's laundering for (the more the better). Why doesn't node-runner just run off with the money when the value sitting in those wallets exceeds a certain value...?

Donno. Good question.

If they are being paid to participate in the network, hopefully the long-term benefit of establishing "cred" (something else that needs working out) will exceed the value of these wallets at any particular time "soon". Like, you can expect to have $50 sitting in those wallets at any one time, but if you just leave your node plugged in and working, you'll have $150 in three months...or something.

Can a node work with the Feds and log all that goes on? Yes they can, but I think that all that needs to be reliably expunged and considered "ephemeral" is the destination chain-address (tuple), that the laundered money should go to. The node keeps in memory, or maybe even a journal that gets pruned, the chain-address pair that the funds should go to after laundering. What if they sell you out? Well, that would be a breach of trust and would jeopardize their key's creds. It might be something the network can be made aware of, at which point the key(s) gets "slashed" or even banned.

How would someone be able to reliably communicate, "they gave me up to the authorities" without it being some kind of malicious act? If the node operator is being properly paranoid, no one will know who the corresponding person is. If your target is a person, maybe it's hopeless? If your target is an address, what would be the incentive? Dealt with an evil address? Well, how did evil address choose this node? Can we disallow picking and choosing your launderer? How does Ethereum choose a block proposer? Something like that? [where the heck does randomness come out of all this?]

It seems the launderer and the laundery both need a concept of "cred".

Lots of frayed ends yet, I know.

Also, any one node has to be trusted this way, so it makes sense that your special key you use to operate node(s) has associated with it a quantifiable amount of trustability cred. Participants on the network prefer to operate on the most trusted nodes, so you should have to work for the benefit of trustability. And if you adjust that curve correctly, the total value of all of the backlogged crypto you are laundering (your slush wallets.) never gets high enough for you to be willing to cheat. The above $50 balance/$50-per-mo ratio can also apply to big players.

And big players can make every bigger efficiency gains: the bigger your total backlog (crypto on hand), the bigger chunks you can move around, which means relatively lower transaction fees. That might also mean that the big players take a longer time... have to wait for the wallets to fill up again... or maybe not: bigger players also have bigger volume! It might not take that long!