Electrum use from third-party Computer

Question

I understand that electrum offer the amazing ability to use the 12 words seed to fully restore a wallet, but that is really dangerous because it doesn't require any password.

Is there a good way to digitally store a backup that enable to regain access to my wallets by entering a password?

P.S. I can export public keys to have a safe read-only wallet backup, but if I export also the private keys will these be password-less and enable anyone who posses them to gain full control of my wallet or do they need to enter the password I provided during the creation phase?

Answer 1

You can set a password for your Electrum wallet by clicking the padlock symbol in the bottom right corner.

This can be a different password for each wallet. The password isn't just a barrier like the PIN of a bank card but the private keys actually are encrypted using it and AES-256-CBC (Source) which means that the password is needed to spend money. However, your transaction history, your own addresses (and therefore how much money you have) can be seen without knowing your password. This is the reason Electrum can give you this info (like your total balance) without requiring you to enter your password first.

If you want to back up your wallet, you can literally just do that because an Electrum wallet is just a single file.

The Electrum folder is ~/.electrum on Linux and Mac and described without slashes for Windows as UsersYourUserNameAppDataRoamingElectrumwallets on the official Electrum website but you'll probably find it. In it, there is a folder named wallets which is the default location for Electrum wallets. The wallets are text files which have the same name as the wallets.

Backing up the wallet files has the added advantage that you get your note-like data back (description of sent transactions, receiving notes, contacts). This obviously can't be generated from the seed because it's data entered by the user after the seed is set. However, it's written to your wallet file and if you copy it to a different computer (or the same computer later on after its hard drive exploded) you get the note-like data back.

Answer 2

When you generate a new seed in Electrum 2 you can select "Options" and choose to add your own words to Electrum's wordlist. The word(s) you add could be a password (passphrase). If someone finds your Electrum wordlist, they can import a correct bitcoin wallet, but they would also need to know your password/passphrase to recreate the wallet that you are using.

Be aware that while many Bitcoin wallets (Trezor, Ledger, Mycelium) use the BIP32/BIP39/BIP44 specifications to create a wordlist, electrum unfortunately uses its own method and worlist. Therefore you cannot import an Electrum wallet to e.g. Mycelium.