How to import a Multi-Sig Wallet to Electrum From Private Keys of Participants?

[hroub]

Hi,

I have the 3 private keys of the 3 participants (3-of-3). Is it possible to import the BTC from the multi-sig address to Electrum wallet?

Thanks

[Xynerise]

If it's a 3 of 3 multisig, in order to import it into Electrum, you'd need all three xprivs (master private keys)
Go to file->New/Restore
Enter a name for your wallet
Select "multisig wallet"
Choose the multisig scheme (eg 2 of 2, 2 of 3, 3 of 3,)
Select "use a master key) if you have the xprivs or "use an existing seed" if you have the seed phrases
Enter the first xpriv, click next
Save the xpub , click next
enter the xpriv or seed of second cosigner, click next
repeat the procedure for the last cosigner
enter a password for the wallet for security, click next
And your multisig is restored.

[Abdussamad]

Edit: seems i misread the question. I know of no way to create an electrum wallet that you can spend from with arbitrary multisig private keys. You can create a watch only wallet though.

[HCP]

I have the 3 private keys of the 3 participants (3-of-3). Is it possible to import the BTC from the multi-sig address to Electrum wallet?

As Abdussamad has said, if the "private keys" that you have are NOT Master Private Keys (ie. xprivs) then you cannot recreate the MultiSig in Electrum.

However, you can certainly get the funds to your Electrum wallet if you have the 3 private keys... One possible option would be to use a service like coinb.in to:

1. Replicate the 3-of-3 MultiSig using the "New -> MultiSig Address" feature of Coinb.in:

• Enter the 3 public keys for the 3 private keys into the boxes provided
• Set "Amount of Signatures required" to 3
• Click Submit
• Double check that the address generated matches the 3-of-3 MultiSig address
• If the address does NOT match, alter the order of the public keys and try again. Continue trying different combinations until you get the correct MultiSig address generated
• Once you have the correct address, make a copy the RedeemScript

and then you can...

2. Create a transaction that spends from that MultiSig Address

• Copy/Paste the "RedeemScript" from Step 1. into the box and click "Load"
• All available "Inputs" (ie. UTXOs) for that address should be loaded (see "Inputs" tab)
• On the "Outputs" tab, enter the destination address (ie. the address from your Electrum wallet) into the Address Box and the amount you want to send
• NOTE: Coinb.in simply uses whatever is NOT sent to Addresses as the fee, so you have to calculate manually. This also means that if you're not wanting to spend EVERYTHING from the MultiSig, you NEED to explicitly specify a Change Address as any unspent funds will be used as a fee!!!
• Once you're happy with your Inputs and Outputs, click "Submit" and you'll get the unsigned transaction hex.
• Copy the unsigned transaction hex
• (Optional, but Recommended) You can input the unsigned hex on the "Verify" page to make sure it is sending the correct amount of coins to the correct addresses and paying the correct fee
• Once you're satifisied, goto the "Sign" page and paste the unsigned hex into the box, and enter the first of your 3 private keys
• Click submit and you'll get a "partially" signed transaction hex
• Copy the partially signed hex
• Again, goto the "Sign" page, but this time, put in the partially signed hex and the second of your 3 private keys
• Click submit and you'll get a second "partially" signed transaction hex
• Copy the second partially signed hex
• Again, goto the "Sign" page, this time, put in the second partially signed hex and the last of your 3 private keys
• Click submit and you'll get a fully signed transaction hex
• (Optional, but Recommended) Double check the fully signed transaction hex on the "Verify" page once more
• Once satisfied that all is OK, goto the "Broadcast" page, enter your fully signed transaction hex and click "Submit"
• congrats, you just created, signed and broadcast a MultiSig transaction

NOTES: You should consider the MultiSig Address (and the 3 private keys used) compromised if you do this... I would not recommend using that address or the private keys again.

[Thirdspace]

However, you can certainly get the funds to your Electrum wallet if you have the 3 private keys... One possible option would be to use a service like coinb.in to:

In fact he's already used coinb.in before you posted this tutorial, and somehow lost partial amount of his transaction.
I'm not sure why he still wants to import it to electrum because those keys already compromised (but coinb.in wasn't the culprit)
after initially accusing coinb.in, later he confirmed otherwise... here's the quote

---snip---
EDIT May 23rd, 2018:

After some further research, I discovered that someone else other than coinb.in may have had access to a private key.
I will update here once I compile some proof and reveal the identity of the scam artist. Sorry if my original post implied that coinb.in was the perp as it doesn't seem very likely anymore.  

NOTES: You should consider the MultiSig Address (and the 3 private keys used) compromised if you do this... I would not recommend using that address or the private keys again.

as long as he is doing it all offline, except retrieving utxo and broadcasting signed raw transaction
I don't see why he should consider it (access to multisig) compromised, he created and owned all the three privkeys
but in this case, yes he shouldn't reuse it because it is confirmed compromised (his transaction was somehow altered)
although quite strange because he only lost partial amount, I'm curious to hear further development of his case

[HCP]

Hah... Guess they won't be too keen to use coinb.in any time soon.

I've used it several times for manually creating transactions and never had it create unknown outputs... But I've always used the "verify" page to double check that the outputs have matched what I wanted.

Not sure how extra outputs were "added"... Obviously that's not possible after signing!!?!

Guessing one of the guys "helping" on reddit got his dark wallet seed... or private keys and has helped themselves to some BTC and cleaned out the BCH.

The "mempool" conflict error he got leads me to believe that the "helper" created and broadcast a transaction first that sent the bulk of the coins as the OP wanted to avoid arousing suspicion while they emptied BCH.

The sending back of coins is just weird tho...