I found a bug in 1.9.6 : If you are disconnected from the net, when you open electrum and choose Restore from seed, you enter the seed, and after it says you are offline it still tries to connect to the server, and it hangs there doing nothing. In windows you can close the "connecting" window and Electrum pops up, but in linux there is no close button in gnome so it just hangs there. Thanks.

Is there a way to disable the Used address hiding ? If there isn't, could you please include an option in the preferences to remove it ? Thanks.
I personally really don't like it for simplicity's sake.

Hope it helps, but this is the list of packages I needed to install Electrum 1.9.6 completely offline on Debian 7.2 :

latest python-qt4 from stable repositories
python-pkg-resources_1.4.2-1_all.deb
python-pip_1.1-3_all.deb
python-setuptools_1.4.2-1_all.deb
python-slowaes_0.1a1-1_all.deb
ecdsa-0.9.tar.gz

I installed them with the following commands :

apt-get install python-qt4 (requires debian installation DVD)
dpkg -i python-pkg-resources_1.4.2-1_all.deb
dpkg -i python-setuptools_1.4.2-1_all.deb
dpkg -i python-pip_1.1-3_all.deb
dpkg -i python-slowaes_0.1a1-1_all.deb
pip install ecdsa-0.9.tar.gz
pip install Electrum-1.9.6.tar.gz

Thank you for your answer. I couldn't find any documentation on this procedure, so I would ask you to clarify it please.

So in the bash console of the offline computer I type
$ electrum -o -w wallet1 deseed
Then take the deseeded wallet file (wallet1) and copy it to the online computer, from the online electrum open the wallet1 file and make a transaction, close electrum.
Then take the wallet1 file and copy it back to the offline computer, open it in electrum... and how do I reseed it ?

Please correct me if I'm wrong, I'm trying to figure this stuff out but can't since there is no documentation.
Thanks in advance.

Hello,
Also regarding the use of an Offline (for signing transactions) and an Online (watch only) computer, is there a way to make the Offline client aware of the transactions that have been broadcasted by the Online wallet, in order for the Offline client to display the proper balance ?

How to create an offline usb key to safely store and spend bitcoins using and Offline Electrum wallet, without having an extra computer.

Let's say you have an onlne computer with windows/mac/linux, and you want to really make sure your bitcoins are safe from hackers, malware, trojans and what not. You can use an Offline Debian installation with Electrum on it to store your bitcoins  and sign transactions.

You need : 1 fast usb stick (so it boots quickly from linux), 1 average usb stick (to transfer the Master Public Key from the Offline Electrum to the Online one, and to transfer transactions) and, 1 blank DVD

- download Debian 7.3, you just need DVD-1 - http://cdimage.debian.org/debian-cd/7.3.0/amd64/iso-dvd/

- burn Debian DVD-1 on the blank DVD

- download Electrum-1.9.6.tar.gz from Electrum website, and also google for :
python-pkg-resources_1.4.2-1_all.deb
python-pip_1.1-3_all.deb
python-setuptools_1.4.2-1_all.deb
python-slowaes_0.1a1-1_all.deb
ecdsa-0.9.tar.gz

- copy the packages to the average usb stick, and disconnect it

- disconnect your other hard drives (to prevent bootloader from rewriting your MBR), disconnect from internet cable (just to be sure), and install debian 7.3 on the fast usb stick.

- when asked "use another DVD image" chose No

- when asked "use network mirror" choose No

- when asked about partitions, choose Guided - use entire disk

- at the Software selection step, just tick : Debian desktop environment, Print server (if you want to be able to print your private keys), Laptop (if you will use the usb stick on a laptop at some point), and Standard System Utilities.

- install the GRUB boot loader on a hard disk, choose YES, otherwise your usb key will not be able to boot linux by itself

- when install is done, you can boot from your new Debian installation

- connect the average usb stick and copy the Electrum packages to Desktop, and keep Debian install DVD inside DVD reader

- make sure to disable the network in the System Setings -> Network.

- open the Terminal app from Applications, and type :
su root
Enter root password.
(if using windows, for the Online Electrum, your clock is set to local time, so make linux also use local time instead of UTC by typing : hwclock --systohc –localtime)
apt-get install python-qt4
cd ~/Desktop
dpkg -i python-pkg-resources_1.4.2-1_all.deb
dpkg -i python-setuptools_1.4.2-1_all.deb
dpkg -i python-pip_1.1-3_all.deb
dpkg -i python-slowaes_0.1a1-1_all.deb
pip install ecdsa-0.9.tar.gz
pip install Electrum-1.9.6.tar.gz

- after that, you can go to /usr/share/applications, find Electrum and right-click -> Copy to Desktop.

- Create a new wallet and write the seed down, go to Settings -> Import/Export and copy your "Master Public Key" and put it in a text file on your average usb stick.

- That’s it, you have your offline debian install ready to use with Electrum.

- Shutdown, reconnect your hard drives and internet cable.

- Boot into your main OS, install Electrum, select Restore in the dialog box shown on the first start up, use the "Master Public Key", and you are ready to go. You can now use the average usb stick to copy transactions from the Online Electrum to the Offline Electrum, for them to be signed.


Why Debian ? because it’s 100% open source, and the kernel does not contain closed source blobs (non-free blobs), so you can trust it has been checked by 3rd parties.

You can try to have Electrum connect manually to some server in the provided list. Electrum does not need open ports, it simply polls the server for updates, so it's firewall friendly.

If all else fails, you can allways use another wallet like blockchain.info or Multibit to spend the bitcoins, by taking the corresponding private key and importing it into the other wallet.