How to sweep a paper wallet into an Electrum wallet using a cold storage setup

[mckennal]

Here is what I'm trying to do, but not sure of exact steps.

1. Send Bitcoin from my exchange account to a paper wallet generated using the offline bitaddress.org on a Tails live booted offline machine. Just keep the public and private keys for this wallet on paper. (I know how to do this step.)

2. When I want to send/sell/etc Bitcoin, I want to sweep my paper wallet bitcoins into Electrum, but I want to use the cold storage setup of Electrum so I don't ever put private keys on a machine that is connected to a network/internet.

How do I generate and save the transaction I want on my internet connected (watch only) Electrum wallet so I can transfer to the offline cold storage Electrum wallet for signing? (again, I'll use Tails for the Electrum cold storage wallet)
Exact steps appreciated, as I've found many similar questions asked and answered, but not this exact scenario

(Apologies in advance if this has been asked before, but I couldn't find this question being asked able a lot of googling!)

Thanks

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[TryNinja]

2. When I want to send/sell/etc Bitcoin, I want to sweep my paper wallet bitcoins into Electrum, but I want to use the cold storage setup of Electrum so I don't ever put private keys on a machine that is connected to a network/internet.

How do I generate and save the transaction I want on my internet connected (watch only) Electrum wallet so I can transfer to the offline cold storage Electrum wallet for signing? (again, I'll use Tails for the Electrum cold storage wallet)

To do this, you will probably need 2 devices.

1 connected to the internet (watch only)
1 not connected to the internet (the wallet itself)

To create those wallets:

• 1. In your connected device: open Electrum to create a new wallet and choose: Standard wallet -> Use public or private keys -> Paste your public key (address); This will be your watch-only wallet.
• 2. In your offline device: do the same as step 1 but with your private key instead of public key.

When you want to spend your coins:

• 1. Go to the connected device, open Electrum -> "Send" -> Fill the address you want to send the coins to and the amount.
• 2. Click "Preview" -> "Save" -> Save the txt file with the unsigned transaction to your flash drive.
• 3. Now go to your offline device and open your offline wallet -> Tools -> Load transaction -> From a file.
• 4. Choose the txt file with your unsigned transaction from step 2.
• 5. Click "Sign" -> "Save" -> Save the signed transaction to your flash drive.
• 6. Now, go to your online device again and:
• a. Broadcast the transaction from a website (e.g: https://live.blockcypher.com/btc/pushtx/).
• b. Load the signed transaction file (just like the step 3) and click "Broadcast" to send the transaction.

Edit: This video follows the same proccess described above - https://www.youtube.com/watch?v=DQumISxkJsQ

[mckennal]

Thanks for your respond TryNinja, but that's not quite what I was asking.

I understand the process you've written down, but I've read that it's easier/better to do a "sweep" than a "send" when using a paper wallet, as you want to make sure the paper wallet is completely drained of funds, and swept into a wallet you own.

Is there a way to use the method you describe but do a "sweep" instead of "send"? I've tried using "sweep" in the online wallet to generate the transaction, but it asks for the private key (for my paper wallet) and I don't want any of my private keys on a network connected computer.

Or, is your method to best way to achieve what I'm trying to achieve?

Thanks!

[clip123]

Yes, follow the process described above and then move ALL the funds from paper wallet to wallet created by Electrum.

[mckennal]

Thanks, that was the last piece of my Bitcoin puzzle!

[HCP]

There is really no difference between a "sweep" and a "send"... both create transactions that transfer coins from one place to another.

The "sweep" functionality is just a convenience function that enables you to send directly from a private key without first importing it into your keystore... Basically it just does this:

- Locates ALL UTXO's for address associated with given private key
- Creates a transaction that sends total value of all found UTXO's to new address specified
- Signs transaction with given private key
- Broadcasts the transaction


You can do the same thing by:

- Importing your private key into "Offline" Electrum
- Importing your address into "Online" Electrum (This finds all the UTXO's)
- Create transaction on "Online" Electrum that transfers ALL the UTXOs to the new address
- Save this "unsigned" transaction
- Transfer "unsigned" transaction to "Offline" Electrum
- Sign the transaction with private key in "Offline" Electrum
- Transfer "signed" transaction back to "Online" Electrum
- Broadcast "signed" transaction


Both methods effectively do the same thing... just one is slightly more time intensive

[Abdussamad]

if you don't mind exposing your paper wallet private keys then just sweeping into a watch only wallet on the online computer will do the job. considering that the paper wallet will be emptied when you sweep it there is minimal risk IMO.

[mckennal]

Thanks @Abdussamad, but I was aiming to not expose private keys at all on the internet connected computer.

Just a slight (pedantic) amendment to the @TryNinja's post (as I just went through and tested the process):
Step 1 of create the wallets - you can't do "New / Restore" -> "Standard Wallet" -> "public or private key" as it will only accept a full master public key, not a single bitcoin address from a paper wallet. You need to do: New/Restore -> "Watch bitcount address" -> Paste your bitcoin address (public) from the paper wallet.
Also, I didn't think there was a need for step 6.a. So I skipped it and went straight to 6.b (as indicated by @HCP) which worked.

I just wanted to put those couple of things down here in case anyone struggles.

Thanks for all your help - I followed the steps, and it all works Greatly appreciated.

[Abdussamad]

once the coins are swept to a new address it won't matter if the paper wallet priv keys have been exposed.