Looking for advice on how to get rid of dusting

[BTCcollector19]

Hi everyone,

I recently discovered some small Satoshi txns that were sent to my wallet without my knowledge.  I'm guessing these are a "dusting" operation.  I'm not doing anything illegal so I'm not worried, but I do consider this to be an aggressive invasion of privacy and it pisses me off.  My first reaction was to find the companies that do this bullshit and spray-paint their developers' cars so they can see what it feels like.  But then I calmed down 😜.  I'm now looking for advice on how to get rid of the dust UTXOs.  My wallet is held on a Trezor.  Thanks in advance for any advice you can offer. 

[Pmalek]

From what I understood about dust transactions is that they are small amount of Bitcoins sent to a wallet whose value is so tiny that it is even lower than the amount of the fee required to spend the bitcoin. That is according to the definition.

Source: https://www.investopedia.com/terms/b/bitcoin-dust.asp

So if someone sent you such a transaction or several of them, that just means that he paid a higher fee than the value of the bitcoins he sent you. Why would you care about that, there is no fee on your side is there? You just leave them there with the rest of your bitcoins in your wallet.

[mocacinno]

Like Pmalek said: don't worry about them...
Even from a privacy standpoint it shouldn't matter... Sure, the person who sent you these dust outputs will be able to see if you use these outputs together with other outputs to create new transactions, but that's about it... Outputs funding addresses in other subwallets won't be used together anyways... Only outputs funding addresses belonging to the same wallet will be combined, it doesn't matter if it's dust or not.

You can always combine these dust unspent outputs in one transaction paying a 1 sat/byte fee and see if you can make some profit from this dust...

[Carlton Banks]

I'm now looking for advice on how to get rid of the dust UTXOs.  My wallet is held on a Trezor.  Thanks in advance for any advice you can offer.  

I think if you used the python-trezor CLI tool, you could spend your own coins without spending the dust. Electrum could also do it, but with a privacy loss.


An additional step could be to spend only your outputs at the spammed address, but specifically use only the dust for the transaction fee There would be no privacy loss, as anyone analysing the transaction already knows you can spend both your output and the spam/dust output, but the tainting would happen to the miner that accepts the transaction instead of to your own money. Probably best to use the entire spam amount as fees

That last idea, python-trezor probably won't let you do directly, the options would be to use:

• Electrum (easy, low privacy)
• A raw transaction using python-trezor and bitcoin-cli together (much more difficult/error prone, high privacy)

If you wanted to practice the 2nd option (python-trezor + bitcoin-cli), you could put some testnet coins on your Trezor to simulate your circumstances, you'd be more confident after that (mistakes can cost you badly, be careful).

You can always combine these dust unspent outputs in one transaction paying a 1 sat/byte fee and see if you can make some profit from this dust...

_Do not do that_ IF the spam is from different addresses. It's an assumption, but a reasonable one, that the person who collected all those separate spam dustings together owns all the addresses the spam was sent to. That harms your privacy.

If you spend a bunch of spam outputs that all get sent to just one address, your privacy cannot be harmed (although the resulting tainted outputs are somewhat unique, if they had been sent in different rounds of dusting from different original addresses). I'd be surprised if a dust spammer did that though.

[mocacinno]

I clearly stated in my previous post that the person who sent the OP these dust outputs would be able to see if he used these outputs together with other outputs to create new transactions, but that's about it... Since he already said that he wasn't doing anything illegal, it looked more like a statement to me (he doesn't like people trying to decrease his pseudo-anonimity)...

In this particular case, if he's fine with somebody being able to identify several addresses as belonging to the same wallet, i feel my advice is still valid and he should be able to combine all the dust inputs and try to make a profit.
IF you don't want your addresses to be linked together, Carlton Banks is correct: you shouldn't use these dust inputs.... Or at least have a solid plan on how to spend them without losing your pseudo-anonimity.

The only point i'd like to raise is that if you use the dust input, it shouldn't matter if you use it to pay the miner's fee... As soon as you use it, people WILL be able to link the address containing the transferred value and the address that was funded with the dust outputs...

For example

Code:

if you create a new transaction with inputs:
unspent output from transaction "1_this_is_a_real_transaction_n_0_is_funding_address_1MyRealAddress_with_value_10000000sat"
and
unspent output from transaction "2_this_is_a_dust_transaction_made_to_decrease_your_privacy_n_0_is_funding_address_1MyVeryPrivateAddress_with_value_10000sat"

And output:
"n_0_funding_address_1DudeIWantToPay_with_10000000sat_leaving_10000sat_as_fee"

People looking at the above transaction will be able to deduce with a certain amount of certainty that your wallet contains both address 1MyRealAddress and 1MyVeryPrivateAddress.. Even if the dust output funding 1MyVeryPrivateAddress was used to pay the miner's fee. Why? Because the miner's fee isn't sent to the miner directly. The miner adds a coinbase transaction funding his own address. In order to determine the value, he subtracts the sum of values of the outputs from the sum of the values of the inputs of every transaction in the block he is solving and adds 12.5 BTC (untill the next halving). Since the miner fee isn't payed directly to the miner, anybody analysing the transaction WILL be able to link the address with the dust to the other addresses whose funding unspent outputs have been spent

[Carlton Banks]

I clearly stated in my previous post that the person who sent the OP these dust outputs would be able to see if he used these outputs together with other outputs to create new transactions, but that's about it...

Yeah, I was just worried people might accidentally remember your last sentence instead of the first two.

For the record: Mocacinno and I agree that combining spam should only be done when the spam was sent to 1 address Don't combine spam together that was sent to 2 or more addresses, or your privacy suffers

[r1s2g3]

Since "dust transaction" topic come up, I am curious what exactly is current limit of minimum amount of BTC can be sent?
I read a very old post from satoshi where minimum was set at .01 BTC ,but I guess at that that time 1 BTC value was  also less than a cent.

[HeRetiK]

Since "dust transaction" topic come up, I am curious what exactly is current limit of minimum amount of BTC can be sent?
I read a very old post from satoshi where minimum was set at .01 BTC ,but I guess at that that time 1 BTC value was  also less than a cent.

546 sats for legacy transactions and 294 sats for (I guess native?) SegWit transactions.

It appears to be implementation dependent though, so to my understanding you could in theory run a node with a smaller dust relay fee and then mine blocks containing transactions below the dust limit (whatever good that would do).

Code:

    // "Dust" is defined in terms of dustRelayFee,
    // which has units satoshis-per-kilobyte.
    // If you'd pay more in fees than the value of the output
    // to spend something, then we consider it dust.
    // A typical spendable non-segwit txout is 34 bytes big, and will
    // need a CTxIn of at least 148 bytes to spend:
    // so dust is a spendable txout less than
    // 182*dustRelayFee/1000 (in satoshis).
    // 546 satoshis at the default rate of 3000 sat/kB.
    // A typical spendable segwit txout is 31 bytes big, and will
    // need a CTxIn of at least 67 bytes to spend:
    // so dust is a spendable txout less than
    // 98*dustRelayFee/1000 (in satoshis).
    // 294 satoshis at the default rate of 3000 sat/kB.