This thing makes your private keys secured but meantime you can't-do that since a wallet needs internet to send. But I dunno if there are existing ways to do that, coz that's all I know.
No I am talking about signing transaction with my private key offline and broadcasting them through online computer or wallet. I have heard somewhere this can be done via electrum or bitkey. Couldn't find any reliable guide till now to do it in right way...
Do you want to do that with two PCs? It's pretty simple. That's how I do:
1. Go to your offline PC and create a wallet with Electrum. Write down your seed, and go to Wallet -> Master Public Keys -> Copy your master public key and save it on a pendrive.
2. Go to your online PC, create a wallet with Electrum but select "Use public or private keys" -> Put there your xpub -> This is your watch-only wallet that will build the transactions, while the offline will sign them.
When you want to spend:
1. Open your watch-only wallet -> go to "Send" as usual and make your transaction -> Click preview -> Click "Save" and save your transaction in a pendrive.
2. Go to the offline PC -> Open your offline wallet -> Go to Tools -> Load transaction -> From a file -> Select the txt file with the transaction you saved in the pendrive.
3. Click "Sign" and save the signed transaction in the same pen drive.
4. Now go to your online PC wallet again -> Tools -> Load transaction -> From a file -> Select the signed transaction -> "Broadcast";
Congrats! Your transaction has been sent
