Electrum won't display Master Public Keys

[nejel]

Following guide http://docs.electrum.org/en/latest/coldstorage.html I intended to spend bitcoins from paper wallet signing transaction on offline machine. So I created Electrum wallet using given private key. However button Wallet -> Master Public Keys is grey, so I can't obtain PubKey and create a watching-only version on online machine. What is the case?

What kind of Public Key is actually needed? I obtained uncompressed -130 characters and compresed -66 characters from bitaddress.org (offline) but it won't go through.

Electrum-2.9.2
Ubuntu-16.04.2

[1715021486]

1715021486

[1715021486]

1715021486

[1715021486]

1715021486

[ranochigo]

Following guide http://docs.electrum.org/en/latest/coldstorage.html I intended to spend bitcoins from paper wallet signing transaction on offline machine. So I created Electrum wallet using given private key. However button Wallet -> Master Public Keys is grey, so I can't obtain PubKey and create a watching-only version on online machine. What is the case?

What kind of Public Key is actually needed? I obtained uncompressed -130 characters and compresed -66 characters from bitaddress.org (offline) but it won't go through.

Electrum-2.9.2
Ubuntu-16.04.2

Master public key is a string of letters that allows the client to generate the public key of any address from a master private key which is generated from a seed. Electrum will not give you any master public key simply because it is not possible to generate one unless you created a new wallet with seed inside of Electrum.

If you wish to create a watch-only wallet, in the setup menu, select "Restore a wallet or import keys" then select standard wallet and paste your Bitcoin address in the box. The procedure for the rest of it will be the same.

[nejel]

Thanks, I've gone a little bit further in the process but another problem occurred. I can't sign transaction because offline wallet restored from private key is related to uncompressed address but transaction with compressed. What can I do about it?

[ranochigo]

Thanks, I've gone a little bit further in the process but another problem occurred. I can't sign transaction because offline wallet restored from private key is related to uncompressed address but transaction with compressed. What can I do about it?

You can convert the address from a compressed key to an uncompressed one, vice versa.

AFAIK, you shouldn't encounter any problems using a uncompressed key in the client. Go to your offline instance of Electrum and go to the address tab. Check your address against the one on your online computer. If they don't match, you have to press Wallet>Import address and paste the address that is shown on your offline computer.

[nejel]

Yes, but my balance is 0 in uncompressed address and I need to spend funds from compressed one. I can't import address on offline computer this way as you pointed. Transactions created on online wallet are treated as unrelated to offline one. So how can I relate my offline wallet with compressed address?

[Abdussamad]

you can't do what you are trying to do with electrum. offline signing with imported private keys is not going to work. at least not via the GUI

[nejel]

Is there any client providing such a possibility? Eventually is there any clear guide how to do it manually?