Bitcoin Forum

Hey guys,

I want a Bitcoin wallet that can be used by 2 people at the same time.
Something like a bank account that can be used by you or your wife.

It''s something like a business account for me and my business partner.
We both need access to this wallet.

You can share a brainwallet/seed with whoever you want. You can also use a wallet file from Bitcoin Core on different installs (as long as you either do offline transactions only or send the file back and forth between you and your partner)

The easyest way would be to use electrum:
Generate a new wallet yourself, send your partner the complete seed and let him recreate your wallet from seed on his pc.
Next, install plugin "labelsync" and force import/export the labels you created :)

The wallet can even be opened two places at once...

It just came to my mind that I can just create a new wallet on a "website" that we can share.
I know this exists for Monero, is it also available for Bitcoin?

it is available, for example on blockchain.info, but online wallets are not secure.... I would never advise anybody to open an online wallet!

Depends on the wallet, not all of them work the same. Regardless of the wallet I dont see a reason why they should not be "online" (I assume you mean running the wallet with this) at the same time.

Coinbase may be a good option for you.  You can both be logged in from different computers and your balance will update in real time to show activity done by one or the other.  You can also have multiple wallets set up for various things.

Who would determine that? There is no central authority that would disconnect one wallet and keep the other online. Chances are very high that both are connected to different nodes (assuming SPV or full node wallets) or servers (electrum) anyway.


Sure it could, but that would be even more likely if one wallet was offline when the other created a TX and come online before the TX was confirmed. When both are online they know about the TX the other creates within seconds. To keep them in sync (in terms of keys) a HD wallet is a must IMHO.

^^ this is why i specifically proposed electrum. I know for a fact that it's possible to have two electrum wallets open at the same time... I do it all the time. Just leave my wallet open at the office, and still open this wallet (generated from the same seed) at home for a quick peek in case i expect some payment.
With the labelsync it's even easy to synchronise your labels between home and office (or in OP's case, between him and his partner).

Offcourse, there is a minimal chance both the OP and his partner generate a transaction with the same inputs at the same time. In this case, i suppose one of the transactions is included in a block, the other one is cancelled. Eventough the chance is really small, i suppose the OP and his partner would have to double check their transactions after 30 minutes to see if they went trough...

They're ok for leaving small 'ish' amounts in for every day spending but you should never leave a decent amount of bitcoin's on an online service where you're not the sole owner of your private key(s).

absolutely . YES it could be done. just have to install the same seed of a wallet on 2 computers , on for bitcoin core, using the same wallet.dat on 2 different computers ( ore more ..)

just out of curiosity: if you use the same wallet.dat on two different computers, won't this cause any problems?
I tought that bitcoind (or bitcoin-qt) would generate new private keys for change addresses. I read somewhere that there were a couple addresses pre-generated, but when they run out, new addresses get generated automatically.

In this case, the OP and his partner would start out with the same private keys in their wallets, but after a while, their wallets wouldn't be the same anymore... Is this correct?

  no, that's not cause any problems ( as i know)   when you do a transaction on a computer it apears on the second one .... thats' all

mocacinno is correct. Bitcoin core should not be used across different machines with the same wallet.dat. It has (by default) 100 private keys and addresses pregenerated for you. If one address is used (e.g. for change) a new is generated to keep the pool of keys at 100. The new one is generated randomly and will be different for both computers. Thus the files are quickly out of sync and need to be manually kept in sync in order to avoid lost coins.

Is a good way to loose money.  Many people that have tried this in the past without understanding the complexities of the decision have permanently lost bitcoins.

Please do not give advice if you don't know what you're talking about.  New users might actually believe you and lose large amounts of money because of the horrible advice you've given.


That is correct.


You are incorrect.  As I said:

Please do not give advice if you don't know what you're talking about.  New users might actually believe you and lose large amounts of money because of the horrible advice you've given.


Thank you shorena for helping to educate the newbies that might have mistakenly believed defcon23

If I were you, I'd create a multisig wallet so that your partner has to specifically ask you or vice versa to accept any transactions...

That's what I was going to say.

^^ This is an even better idear... Would it be possible to make a 3-party multisig wallet requiring 2 signatures? That way, you could give an official notary the third signature in case of a death/legal issues???
I'm just trying to learn about multisig myself, i have little knowledge about how this technically works :)

You could do that, its very easy.

Just you import the private key into online wallet like blockchain wallet, and at the same time, tell your partner to create another blockchain wallet, and import same key.

So both will have access to same address.

How hard it is?

I didn't understand something.
 If i have core wallet with full blockchain synchronized, i could insert wallet1.dat send some coins..
Then backup wallet1 and insert wallet2.dat without any consequences.
This way i can have as much wallets as i like?
If i forget to return wallet.dat, wallet will create new wallet.dat .
What do you say?

Yes, every switch needs a quick rescan thats it. Well, unless you run core in pruned mode in which case you can not switch wallets without redownloading the entire blockchain.


Correct, Im not sure how this is relevant to the topic at hand though. Core is a bad choice for a wallet to be handled on different machines as I already said above and as was confirmed by Danny (and probably others). It would make more sense to use an HD or online wallet for this sort of thing.

I've been using it like that,
the same PrivateKey are in two different wallet, i put in blockchain.info and in my node.

Blockchain.info sends the transaction back to the origin address. Since Bitcoin Core constantly uses change address for new transactions, you have to constantly re-add the new change address to blockchain.info.

It is possible to use the same seed on HD wallets on the same time though since all the change address can be determined from the seed.

it is perfectly safe*, if you take some simple notes, to use one wallet with two computers, just make use you always use coin control and send small change coins first when they have enough confirmations(medium priority).

change amounts are quite small, most of the time they are from 0,010xxxxx to 0,019xxxxx, you can always send to console - keypoolrefil 1000 before copying wallet.dat it will make your wallet bigger with 1000 change addresses

before deleting one wallet check if balance is equal to another by comparing output of - listaddressgroupings - typed in console, dump/import the missing address

there is an option to send change to custom address also

* - in fact you have double backup if one PC HDD fails, but you have double weak points if one PC is compromised by a trojan virus.

You are funny.

"Its perfectly safe you just have to

#1 create 1000 addresses in advance
#2 think which inputs to spend every time you create a transaction
#3 take extra caution against viruses."

Just use electrum, multibit HD or any other HD wallet.