Ok... I *think* I might have this all figured out... I can't test it, as I don't have any coins in a MultiSig address, so the Lumens claim form won't let me get to the message signing part. So,
this method is 100% UNTESTED!NOTE: Please consider the risks of potentially "exposing" your xprv's... you should run offline copies of all websites, and run them using non-networked Virtual Machines or air gapped PCs or "Live" distro's if possible. I will not be held accountable for any loss of coins should you choose to follow these instructions!HCP's extremely complicated 12 Step Method for claiming Lumens from an Electrum 2FA MultiSig AddressStep 1. Before you start, create offline versions of:
https://coinb.in/#verifyhttps://iancoleman.github.io/bip39/Step 2. Retrieve your redeem script. This can be achieved following the previous instructions here:
https://bitcointalk.org/index.php?topic=1989369.msg19830190#msg19830190Step 3. Once you have your redeem script, you can identify the P2PKH (aka "1") addresses that you need to sign your message with by using the following site:
https://coinb.in/#verify Again, you should really download an offline copy (link provided at the bottom of the website!)
Step 4. "Restore" your Electrum 2FA wallet ("File" -> "New/Restore" -> Call it "restored2FA" and click "Next" -> "Wallet with two-factor authentication" -> "I already have a seed" -> [Enter your seed] and click "Next" ->
"Disable" -> Don't enter a password and click "Next"
WARNING: This creates an unencrypted wallet that has your xprv in PLAINTEXT hence the warnings about doing this OFFLINE!!!Step 5. Find your "restored2FA" wallet file (%appdata%\Electrum\wallets) and open it in the Text editor of your choice. You should find sections labelled "x1/" and "x2/" that contain your two xprv "rootKeys":
Step 6. Using your offline copy of
https://iancoleman.github.io/bip39/ - Put the "x1/" xprv into the "BIP32 Root Key" section (leave mnemonic empty). Select "BIP32" under Derivation Path. Set "Client" to "Custom Derivation" and set the Derivation Path to "m/0":
NOTE: if your original "3" address was a "Change" address (check the address tab in Electrum), you need to use "m/1"Step 7. Hunt through the list of generated addresses until you find one that matches one of the "1" addresses generated in Step 3 (The PubKey should also match one of the PubKeys used to generate your redeem script in Step 2):
Congratulations, you now have the private key for one of your 3 "MultiSig" addresses.
Step 8. Repeat Steps 6 and 7 using the "x2/" xprv... you now have 2 of your 3 private keys!
Step 9. Import those private keys into a "standard" Electrum wallet ("File" -> "New/Restore" -> "Standard Wallet" ->
"Use public or private keys" -> Copy/Paste the private keys and click "Next"... and use them to sign the Stellar/Lumens verification message as required.
Step 10. Make sure you have deleted the unencrypted "restored2FA" wallet. or alternatively, move all your coins out of your 2FA wallet as you should probably consider it compromised.
Step 11. Enjoy your Lumens
(Optional) Step 12. Consider a tip if this actually works!
As an alternative to using the
https://iancoleman.github.io/bip39/ website, you can just create a new Electrum wallet, and import the xprv: "File" -> "New/Restore" -> "Standard Wallet" -> "Use public or private keys" -> Copy/Paste the "x1/" xprv and click "Next". Your wallet should generate the required address. Check the "address" tab, you may need to select "Wallet" -> "Addresses" if it is not visible:
You can then right click this and "Sign/Verify Message"... you will need to then "restore" another wallet using the "x2/" xpriv, and sign the message using the 2nd required address.
Personally, I think I prefer the BIP39 website method as it creates only one wallet that has both the private keys for signing the message.