How to run Electrum on an Airgapped device for Cold storage.

[Audrey Simmons]

One of the very few questions, that will be asked in this procedure is how to download Electrum on an Airgapped computer?

Airgapped computer is a device that hasn't been connected to the internet, you can create an airgapped device by simply disconnecting every internet capable or connections (wifi) from your computer, flash drive, bluetooths and also changing the hard drive, reinstalling a new Windows using a USB or CD/DVD depending.

Imagine you are done setting up your airgapped device, in order to install Electrum to the device without downloading it online, these are the procedures;

1. There should be another device connected to the internet which will be used to download Electrum from the official developers site,


The one with exe. is the executable file to run Electrum.
The one with exe.asc is used to verify the signature if downloaded from the correct source.

2. Copy all the downloaded files straight to a new USB that has not been used, this is a protection in case of drive corruption.

3. Extract the USB drive and plug in to your air gapped device, install the file and run Electrum.
Electrum does not require the internet to be installed or to create wallets.

4. Run Electrum, create your wallet, write down your seed phrase and copy Public key which will be used to create a watch only wallet.
* Copy the public key from Electrum in your airgapped device, save it to the USB.
* Plug the USB into your other computer (the one connected to the internet).
* Open Electrum, create a new wallet, a standard wallet using the public key, extract the public key from the USB drive and launch file, it will fill in your master public key, which will create your watch only wallet.

Watch only wallets are used to check transactions, it can not be used for spending Bitcoin.

[Tungbulu]

If I were you, I’d be extremely careful with the verification step you stated, because simply downloading the .exe and .asc files is far from being enough. I’ll advise you to also verify Electrum’s signature on the online computer before moving ahead to transfer the installer to the airgapped machine you’re using.

Secondly, an airgapped computer doesn’t necessarily require you to completely replace the hard drive or reinstall windows, the most important part that you should focus more on is ensuring that it has no network connectivity.

And then thirdly, when setting up the wallet, you need to avoid storing the seed on the USB or transferring it to the online machine, the only thing that’s allowed to leave the airgapped machine are the appropriate public information, such as the public key.

And one more thing, I’d like to know, during the point of transferring the master public key from the airgapped machine/computer to the online computer, what method would you suggest should be recommended to truly verify that the data wasn’t actually modified or changed during the transfer process?

[Karl_3000]

After I set up the wallet, I will prefer to use QR code generated on the wallet on air gapped device and camera from the watch only wallet to transfer addresses, master public key, BPST and BST. I will not do any interaction with the USB stick longer. Electrum cold wallet is very safe but you need to also stay away from scammers.

[Sim_card]

After I set up the wallet, I will prefer to use QR code generated on the wallet on air gapped device and camera from the watch only wallet to transfer addresses, master public key, BPST and BST. I will not do any interaction with the USB stick longer. Electrum cold wallet is very safe but you need to also stay away from scammers.

You can use the QR code or USB stick it's still the same thing. I will also say that it's good we learn the habit of always using passphrase to add to your seed phrase so that, it will be difficult for anyone to compromise your wallet if they see your seed phrase. As long as your wallet is always offline, scammers wouldn't have access to it.

[Karl_3000]

You can use the QR code or USB stick it's still the same thing. I will also say that it's good we learn the habit of always using passphrase to add to your seed phrase so that, it will be difficult for anyone to compromise your wallet if they see your seed phrase. As long as your wallet is always offline, scammers wouldn't have access to it.

The QR code is not the same thing to using the USB stick but you can say that both can be used to achieve the same result, another thing is that the QR code is safer. Another advantage of the QR code is that it is super fast and make what you are sending between the air gapped device and watch only wallet to be easier.

[Audrey Simmons]

And one more thing, I’d like to know, during the point of transferring the master public key from the airgapped machine/computer to the online computer, what method would you suggest should be recommended to truly verify that the data wasn’t actually modified or changed during the transfer process?

Karl_3000 gave a nice response, you can stick with what he said, QR Scanner is another good suggestion.

After I set up the wallet, I will prefer to use QR code generated on the wallet on air gapped device and camera from the watch only wallet to transfer addresses, master public key, BPST and BST. I will not do any interaction with the USB stick longer. Electrum cold wallet is very safe but you need to also stay away from scammers.

[Tungbulu]

And one more thing, I’d like to know, during the point of transferring the master public key from the airgapped machine/computer to the online computer, what method would you suggest should be recommended to truly verify that the data wasn’t actually modified or changed during the transfer process?

Karl_3000 gave a nice response, you can stick with what he said, QR Scanner is another good suggestion.

That’s right. With QR scanning, the process becomes way more convenient, especially since this doesn’t process automatically avoids physically connecting the two devices. One extra cautionary step I also try to take is to still verify the resulting addresses on both the watch only and the offline wallet afterwards, just to make sure that the public key was actually transferred correctly.

[Charles-Tim]

One extra cautionary step I also try to take is to still verify the resulting addresses on both the watch only and the offline wallet afterwards, just to make sure that the public key was actually transferred correctly.

Another thing people should pay attention to mosly is clipboard malware not to change the address on the watch-only wallet to a hackers address. The hackers address will be what that will be displayed on QR code. Which means the QR code address and the address on the unsigned transaction can be the same, belonging to a hacker, but caused by clipboard malware.

[promise444c5]

* Copy the public key from Electrum in your airgapped device, save it to the USB.
* Plug the USB into your other computer (the one connected to the internet).
* Open Electrum, create a new wallet, a standard wallet using the public key, extract the public key from the USB drive and launch file, it will fill in your master public key, which will create your watch only wallet.

Watch only wallets are used to check transactions, it can not be used for spending Bitcoin.

I think you’re confusing a public key with master public key..

A single pub key works for just only one address.. it’s useful in such cases only when you are working with private key. Otherwise, you need a master public key to create a watch only wallet that checks for all the addresses of a HD wallet.

Change the third line as well to master public key

[Mia Chloe]

~snip

Understand something clearly.... Downloading online isn't actually a problem at all the real problem actually is downloading an authentic software and being able to verify its authenticity. Basically even if you bring that software from a flash or CD drive you are not safe unless it's authentic.

The truth is at some point in time that software still came from an online source so transfering to a flash or drive doesn't make it safe. If it is bugged it's still gonna be bugged on an airgapped device regardless. You should make more comments on verifying than actual transfer.

[Alvin_talk]

While performing all these procedures stated by the OP, ensure you only download the electrum wallet from their official site: https://electrum.org/
Do not download through any third party sites for your own safety and security.

[Mia Chloe]

After I set up the wallet, I will prefer to use QR code generated on the wallet on air gapped device and camera from the watch only wallet to transfer addresses, master public key, BPST and BST. I will not do any interaction with the USB stick longer. Electrum cold wallet is very safe but you need to also stay away from scammers.

QR codes don't make you safer either. Courtesy suggests if you intend using a stick you'll properly format it obviously on a device that is also clean too. It is way better than scanning a QR code especially if you are on a mobile device most of them read QR codes straight to your clip board and clip board viruses can be very dangerous too.

The point is regardless of the method you make use of you've just gotta be careful nothing is a hundred percent safe and that includes hardware wallets and airgapped devices.