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OFFLINE Electrum

If you care about security and don't feel like buyingツTrezor, you may want to keep your bitcoins in anツoffline walletツalso known asツcold storage.

Cold storage is a wallet that isn't connected to any network thus it'sツnot vulnerable to online attacks. It can only be accessed physically which makes itツvery secure.

To set up one, you need an (old) computer and a wallet software that is able to import, sign and export transactions.

You'll also have to run a "watch-only" wallet on another computer that is only able toツview transaction historyツand outputs (wallet addresses) of the cold storage but can't spend them.

This wallet can be "online" because itツdoesn't contain any private keys.

In this tutorial, I'll be using the latestツElectrumwallet 2.8.2 on both computers.


Create an offline wallet

Open Electrum, clickツFile -> New/Restoreツ and create a name for the wallet. Let's call it "offline" for the purpose of the tutorial.

Choose the wallet type. We'll use a "Standard wallet" but you can use any type except for "Watch Bitcoin addresses".

Make sure "Create a new seed" is selected and go to the next step.

You'll be presented with aツmnemonic code consisting of 12 words.

Write it down on a piece of paper and store it somewhere safe!


In the next step, you'll have to retype the words again. After that, your wallet will be created and ready to be used.

Get a master public key by clickingツWallet -> Master public keys.

This key will be used to derivate all bitcoin addresses of the offline wallet.

Copy & paste it to a text file andツtransfer it to the online computerツusingツa USB stick. If you don't have a USB drive you can

If you don't have a USB drive you can click a QR icon in the bottom right corner to view the key's QR code. Scan it with your phone and send it to your online computer.

How to Install an Electrum Server using Full Bitcoin Node and ElectrumX

Create an online wallet

Back on your online computer, start by a creating aツwatch-only walletツwhich you can't spend from.

Go toツFile -> New/Restore, create a new wallet (let's call it "online"), choose the wallet type and select "Use public or private keys".

Paste theツmaster public keyツfrom the offline wallet into the form and click "Next".

A new watch-only wallet with all the offline wallet's addresses will be created.

We will use it to create andツbroadcast a transactionツthat will beツsigned on the offline computer.

Set up your own Electrum server to use it with Electrum wallet

But before you can start using it you need toツload it with some bitcoins. Go to "Receive" tab and send some money to a generated wallet address of the offline wallet.

Create an unsigned transaction

On yourツwatch-only online wallet, go to "Send" tab, fill in transaction details and click "Preview".

A transaction window will pop up with details about the transaction, such as inputs, outputs, the amount and the fee.

Click "Save" and save the "unsigned.txn" file to your USB stick.

Sign the transaction

Now go back to your offline computer and go toツTools -> Load transaction -> From fileツand select the file from the USB stick.

The transaction window will pop up again but this time with an option toツsign the transaction.

You may be prompted toツtype in the passwordツif your wallet is secured with one (it's recommended).

Upon signing the transaction have a look at the field "Transaction ID" which changed from "unknown" to a seemingly random string.

The transaction is now ready to be broadcasted on the network.

Click "Save" and save the new file to your USB stick again.

Broadcast the signed transaction

Go back to the online watch-only wallet and openツTools -> Load transaction -> From fileツagain.

A window with the signed transaction detail will show up again.

Check the corresponding values and if it's alright click "Broadcast".ツThe transaction will then be sent to ever Bitcoin node on the network and eventually mined by a miner.


Running a cold storage may seem like an annoyance and quite difficult to set up. But if you hold aツsignificant amount of bitcoinsyou don't want to risk getting it stolen.

If you for whatever reason don't want to useツTrezor,ツcold storage may be a good compromise between the convenience of a hardware wallet and the security of a paper wallet.


0 #1 Guest 2018-09-19 04:41
Hi! Do yoou know if they make any plugins to protect against hackers?
I'm kinda paranoid aout losing everything I've worked hard on. Any suggestions?

Here iis myy hoepage -______ __ __ hg

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