Topic: How to stop unconfirmed incoming tx tie up your funds you already have? (Read 197 times)

Dust Attack, what it is, why it is dangerous and how to prevent falling to it

Dust attacks are bad for your privacy because if you consolidate them together and use it together with other UTXOs for your transaction, your privacy will be broken. Attackers can link  your addresses, UTXOs together.

Another risk is if you don't know and do consolidation of small dust UTXOs, you will waste many satoshi for transaction fee.

Electrum provides the user with a lot of freedom on how they want to spend their coins. You can always see which of your UTXOs are confirmed and which are still in unconfirmed status. Using coin control, you select what you want based on your criteria. By freezing certain UTXOs, you won't be able to use them for upcoming payments until you unfreeze them. You can also label each of your transactions however you want. That can be beneficial for future transactions.

The coin control is automatically reset if you close and reopen your wallet. But, the frozen coins remains frozen even if you close and reopen your wallet.

It may worth mentioning that there's also a "Fully Spend" option in right click menu which may be helpful to you.


With using all those 40 UTXOs, they are all consolidated and that can make your next transactions cheaper.
That's very useful, if the transaction including those 40 UTXOs can be made with low fee rate.

Due to privacy reasons, electrum doesn't do so by default, if your UTXOs are associated with different addresses.

Thanks everyone for all of your help to gain understanding of this.
Electrum has a lot of features to learn.

Yeah! It's just because  the same address gets alot of inputs the only way to avoid this if you care about your primacy is
Inputs consolidation: you spend all your inputs in a single transaction  when the fee is quite low to a new adresss
You can check
https://bitcointalksearch.org/topic/aug-2022-mempool-empty-use-this-opportunity-to-consolidate-your-small-inputs-2848987

I haven't used Bitcoin core for any transaction because I couldn't  meet up with the sync process so I cannot really answer if Bitcoin core does that but as have said earlier,

Generally, every transaction in bitcoin spends all inputs same experience  with Sparrow  so I think Bitcoin core will also do same
You can check
https://learnmeabitcoin.com/beginners/guide/transactions/
Privacy

The electrum coin selection algorithm which prioritizes all selection of UTXOs on that address is base on their own method of privacy control. As they think a single utxo from that address exposes one privacy. This is just their own way of privacy control which definitely doesn’t goes for most users that’s why there is the coin control protocol.

Here is the quote to their statement on GitHub



As for the coin control protocol I think you need to mark this coins every time you need to make use of them in a transaction after closing the electrum app. If you wish to permanently ban a utxo the thing to use is the freeze coin option instead.

Thanks that was very helpful I see exactly what you mean.
I am going to use coin control for all tx in the future I think.
I can just add more uxto (coins) to the coin control as required.
When you add a coin or uxto to coin control does electrum remember that next session or you need to re add and reference dust attack coins each time?


Does anyone know why electrum is set up to use all input uxto on the same address? Even when just 1 input uxto has sufficient funds to make the spend?

This is very strange default isnt it?
Or is there a reason ?
If you set up a watch only wallet using only a single public address not xpub
Then change is always sent to that same address. Not a different change address.

So can anyone explain why if you have 40 uxto each having more than the single spend amount. Why electrum wants to use 40 inputs?
It could use just 1 uxto input.

Is there a reason specifically related to a watch only single address wallet?
I suppose after the first time it moves all of you coins from all of the 40 uxto and then send the change to the Sam's address , will that be in 1 big uxto clump? So only the first time it spends with a huge tx fee and the following times it will be just a single input and be much cheaper tx fee?

Is the reason electrum uses every single input when it could use just 1 input because it is attempting to organize or consolidate your uxtos?
Or is that not why electrum does this?
Thanks.

Edit /

Thanks promise444c5

This is true. I think electrum always wants to spend your entire balance even for a tiny spend and then send you all your change back usually to a new address for privacy and security.

This is very expensive in fees right now and if you have a watch only wallet created from a single public address then the change can only be sent back to that address. So it seems crazy to pay for 40 input uxtos rather than just 1.

Is that correct ?

Are there issues you can create using coin control with watch only wallet on a single public address?
I just wondered why electrum does not default to using a single uxto input for a spend in this case.
Thanks for everyones information. Very helpful.
Does bitcoin core auto use all uxto and send the entire balance of an address then send the change to a new address also or is that just electrum?

Yes you can do that by selecting  the "spend only confirmed coins" or disabling "spend unconfirmed "
By default the coin control is hidden on electrum because generally
If you tend to spend or spend part of your coinfrom your inputs   then you are spending all coin available in your wallet(as a single output) and receive a UTXO as a change from your spending  
You can actually  control how you want your coin to be spent by
If you wish you use a view only wallet then you can  choose to use it  along with an airgapped  device as a cold storage  to sign your transaction for broadcast

There's no problem or danger with importing a wallet as watch-only it's the best thing you do if you only signing transactions on an airgap device like a phone.

Coin control is what you need if you don't want to spend any unconfirmed transaction check the image below you can also ignore and don't add other coins if you don't want to spend them all(Confirmed or not).



Once you add a confirmed transactions that's the only coins you can spend on the send tab.

Thank you for the idea.

So you think I should put a tick next to ^ spend only confirmed coins ^  this will stop electrum trying to send out any unconfirmed low tx fee coins I will eventually receive? I dont need to use these and prefer to let them confirm before spending them. I don't want to mix them in the send with my confirmed coins.

You touch on an interesting point with coin control in electrum.
I have noticed that I set up a watch only wallet with electrum using only the import a single public address way.
This way it always sends my change to the same address that im sending from.

However. For some strange reason. If I am only spending a tiny amount of btc. Electrum wants to use every single input to that address.
This is unexplainable to me because each input uxto has enough alone for the small spend. Why would it do this?

Why would electrum choose to use every single input when 1 alone would suffice?
I noticed another guy asked this and when I checked it is happening to me also.
I am paying huge fees for very large tx size when I'm sure if I use coin control I can select to use just 1 input uxto. Not loads of inputs.

Is there a danger of doing this using a watch only wallet that spends the change to the same sending address?
I have not meddled with coin control before. Are there things to be wary of?

Thanks for any insight.


Replying to Charles-Tim.

these small dusting attacks can be dangerous?
What can they do to a watch only wallet behind t or

Thanks

On Electrum, you can freeze coins that are not yet having any confirmation. Just go to coins (coin control), you will see the coin (that is not yet confirmed) and you can freeze it.

I will prefer to use another wallet with new seed phrase entirely if dust coin is sent to any of my addresses.

If they pay you with a small fee you can do a CPFP so it shouldn't be a problem because anytime you can make a transaction with the unconfirmed transaction and add an extra fee but to make sure it would confirm check it first on the blockchain explorer if it's not a series of unconfirmed transaction because if it's a series of unconfirmed transaction even you do CPFP with high fee there still a possibility the transaction will be rejected.

Or you can just wait until the receive transaction is confirmed before you spend since Electrum has coin control it shouldn't be a problem if you want to spend only confirmed transactions.

If people send you some bitcoins but use a low fee It can stay unconfirmed for a long time.  You dont actually have those coins yet.

If you want to continue to spend and use your fully confirmed funds without mingling in these unconfirmed funds is the best way to ensure there is a tick next to the option ^ spend only confirmed coins ?

Will making sure that has a tick next to it

A/ stop you spending any of your coins until these coins sent to you with low fees confirm fully

Or

B/ electrum will ignore those low fee unconfirmed coins and just spend from your confirmed coins?

I am wondering why it is unticked by default? I see someone sending me some bitcoin with 5 sats fees.
That will likely not get confirmed for a long time so I dont want that to mess up my confirmed funds.


So if I put a tick next to the spend only confirmed what will happen A or B.

I assumed B but seeing the tick is not there by default made me doubt and I cannot find the exact answer.

Thanks.