Disposing of "dust attack" UTXOs

[bubb1es]

@nothingmuch

fwiw this isn’t my approach, IIRC it’s how dustbgone was implemented

I double checked and yes you are correct, in dustbgone Peter constructs a tx with NONE|ANYONECANPAY inputs and a single empty OP_RETURN output. So very much like this BIP proposal in those regards.

@nothingmuch

or put more simply, the DoS surface is substantially reduced if the rule is that dust spends are only relayed as 1 input transactions, even though these can be freely aggregated by anyone. compact block relay could also be extended to take this special case into account.

Thanks for the details, I understand the DoS issue better now and why the policy carveout would help. I certainly hope we eventually see enough dust UTXOs being disposed this way that a policy carveout is needed. My more immediate concern is having a spec wallets can implement that is safe and effective before the problem gets any worse.