Coin control, what addresses can and can`t be used for change

LoyceV

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Quote from: curious droid on June 09, 2021, 08:27:37 AM

what to do with the funds in change address?

Anything you want

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Now all i have in my wallet is 2btc which seats under change address, what is the best and proper way (besides mixing coins) to use these funds ?

Unless you're trying to hide where you send the 2btc, you can just spend it normally. Chances are the person you sent 3btc can see the address you send the 2btc to, but usually that's not much of a concern.

Quote

i cant get it how do you avoid reusing, you eventually will have to use fund from change address, and whatever transaction you do it will consider reusing.

Just in case: change addresses are no "special" addresses, they're just regular Bitcoin addresses used by your wallet. If you don't change anything, Bitcoin Core will use a new change address every time.
The general recommendation is not to use the same address twice, that doesn't mean you can't use the funds sent to the change address.

There are also reasons to reuse addresses, and I often do it too. It's not necessarily a bad thing, as long as you're aware of the (possible) privacy implications.

Update: I type too slow Tongue

curious droid

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Now I understand it

THANK YOU ALL FOR YOUR SUPPORT

hosseinimr93

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Quote from: curious droid on June 09, 2021, 08:27:37 AM

As many of you suggests to never reuse addresses, i cant get it how do you avoid reusing, you eventually will have to use fund from change address, and whatever transaction you do it will consider reusing.

Not reusing an address means not using an address for receiving bitcoin multiple times and not using the sending address as the change address.
It doesn't mean you shouldn't spend the fund you have received.

You should use every address two times. One time for receiving bitcoin and one time for spending bitcoin. After that you should no longer use that address.

Again, note that you can use any bitcoin address numerous times. You shouldn't reuse an address only if you want to protect your privacy.

mocacinno

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Quote from: curious droid on June 09, 2021, 08:27:37 AM

--snip--
As many of you suggests to never reuse addresses, i cant get it how do you avoid reusing, you eventually will have to use fund from change address, and whatever transaction you do it will consider reusing.

Without adding to the rest of the discussion (all other topics were already answered pretty well), i wanted to point out that there's a difference between using and re-using.

If you fund your change address with an unspent output, offcource you can spend this unspent output (using).
Re-using is funding your change address with an unspent output, spending this unspent output, and afterwards funding the exact same address with a new unspent output again...

curious droid

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ok i will ask this way, what to do with the funds in change address?
I have 5btc it my entire wallet, it came it me as one whole output. Now i spend 3btc and the remaining 2btc i receive on my new address in the same wallet.
Now all i have in my wallet is 2btc which seats under change address, what is the best and proper way (besides mixing coins) to use these funds ?

As many of you suggests to never reuse addresses, i cant get it how do you avoid reusing, you eventually will have to use fund from change address, and whatever transaction you do it will consider reusing.

LoyceV

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Quote from: curious droid on June 09, 2021, 07:39:11 AM

eventually i will have to use up the amount from change address

There no limit to how many change addresses you can use/create.

hosseinimr93

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Quote from: curious droid on June 09, 2021, 07:39:11 AM

as on of the comments suggest to avoid reusing change address, makes me confuse, because eventually i will have to use up the amount from change address, so i will have to use it somehow. How then can i avoid reusing the change address?

All is related to your privacy.
It is always recommended to not reuse addresses. There's no difference if the address is a change address or not.
Let's say you are supposed to send me bitcoin. If I give you a used address, you can check all my previous transactions easily.

It is also recommended to not use the sending address as the change address and always use a new address as your change address. In this way, the remainder of your fund is moved to a new address after every transaction and tracking your previous transactions becomes difficult.
If you use the sending address as the change address, it's easy for every one to find out which output is the change and which one is the recipient address.

Little Mouse

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Quote from: curious droid on June 09, 2021, 07:39:11 AM

i will have to use up fund from that address, thus sending them to someone as a payment or sending to my own wallet but to complete new/unused address

If you want to have untraceable transactions, you can use bitcoin mixing sites like ChipMixer, mycryptomixer, also you can use wasabi wallet. Otherwise, BTC transactions are transparent and you have to leave a footprint all the time. Make sure you are using the official site only.

curious droid

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Thank you ALL for your answers!!!!

as on of the comments suggest to avoid reusing change address, makes me confuse, because eventually i will have to use up the amount from change address, so i will have to use it somehow. How then can i avoid reusing the change address?
I understand that that change address i will label as a change address and never use again as a second change address but the i will have to use up fund from that address, thus sending them to someone as a payment or sending to my own wallet but to complete new/unused address

LoyceV

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Quote from: curious droid on June 09, 2021, 07:06:39 AM

i want to send 3 btc to someone, but the remaining 1 btc i dont want back to my Core wallet but i want to transfer it to my electrum, so if i use my electrum address as a change address in Core will it go to my electrum?

Although you can use a change address for this, the proper way to do it is use "Add Recipient", and add your Electrum address there. You can tick "Subtract fee from amount" so you don't have to subtract the total fee.

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I have 5 btc in Core wallet, i want to send 3btc to Alice and 2 btc to Bob, to make it all in one transaction can i send 3btc to Alice and use Bob`s address as a change address, thus Alice will get 3btc and the remaining change of 2btc will go to Bob.

I wouldn't do this, you risk sending your entire balance to the change address if you have more funds in your wallet, especially if you don't use Coin Control Features.

TL;DR it works, but you should know all the risks.

nc50lc

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If you have more than one large inputs and the amount you want to send only requires one for example, using the custom change wont send all of your remaining balance to the specified change address, only the remaining amount from the used input.
If you want to send all of the remaining balance from Bitcoin core to Electrum, just add it as a new recipient ("+ Add Recipient" button below) and click "Use available balance" once you've filled up the other outputs.

When you click the 'add recipient' button, another "pay To" field will be generated, if your Bitcoin core's window is small, you'll have to use the scroll on the right to see the second payTo field.

ranochigo

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Quote from: jackg on June 09, 2021, 07:10:45 AM

I'd recommend not sending the change to an address that you're going to reuse for better security (just in case) but it's not yet a problem if you do - with larger amounts though I'd support changing the address. Essentially if it's worth it, change it. [extra explanation if you want it] Essentially not reusing addresses or reusing them minimally ensures that if the encryption/signature algorithm is broken, you've got another layer to rely on.

Security is a non-issue as of now. There is no evidence that something like this is possible today nor would it be cost effective even if it is.

The argument against user's specified change address or address reuse is primarily about the privacy.

jackg

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Yes you can set the change address to any bitcoin address.

I'd recommend not sending the change to an address that you're going to reuse for better security (just in case) but it's not yet a problem if you do - with larger amounts though I'd support changing the address. Essentially if it's worth it, change it. [extra explanation if you want it] Essentially not reusing addresses or reusing them minimally ensures that if the encryption/signature algorithm is broken, you've got another layer to rely on.

ranochigo

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Yes correct. The remainder after subtracting both your sending amount and the fees will be sent to the change address.

AFAIK, Core doesn't limit the use of change address, specifically with user specified ones. It's fine to be using your own if desired. Core checks if the addresses are from your current wallet but it would just throw a warning, nothing much.

curious droid

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Bitcoin Core gives me an option to use custom address as my change address.
The question is: can i provide my electrum address as a change address in Core? For example i have 4 btc on my Core wallet, i want to send 3 btc to someone, but the remaining 1 btc i dont want back to my Core wallet but i want to transfer it to my electrum, so if i use my electrum address as a change address in Core will it go to my electrum?

Another example: I have 5 btc in Core wallet, i want to send 3btc to Alice and 2 btc to Bob, to make it all in one transaction can i send 3btc to Alice and use Bob`s address as a change address, thus Alice will get 3btc and the remaining change of 2btc will go to Bob.

Topic: Coin control, what addresses can and can`t be used for change (Read 153 times)