DIY,Bitcoin cold wallet USB stick creation step by step guide

[huanghq]

DIY,Bitcoin cold wallet USB stick creation step by step guide

Preface

This guide select Electrum and Ubuntu OS to create bitcoin cold wallet USB stick.
Electrum is a light-weight bitcoin wallet, it doesn’t require the bitcoin block chain
data on local and easy to use for newbie.

We trust that the Ubuntu and Electrum downloaded from related official site are
security and reliable.

In the guide，We will create a persistent LiveUsb stick and offline install electrum
wallet.

Requirements
1, One Ubuntu14.04.1 CD. We can download Ubuntu14.04.1 32bits desktop ISO file
and burn it on CD。
2, One USB stick,USB3.0 is better.
3, Ubuntu14.04.1 32bits desktop ISO file from official site.
4, Electrum software from official site.
File list：

File list：
1，file：ubuntu-14.04.1-desktop-i386.iso
md5: a4fc15313ef2a516bfbf83ce44281535
Official web page://www.ubuntu.com/download/desktop
2，file：Electrum-1.9.8.zip
md5: 0f91f548ba64b1f5776a28b1522f07ec
Official web page：https://www.electrum.org/download.html


The MD5 values of Ubuntu and Electrum can be found on official site.
Download above files,and record MD5 values on text file for verify.

MD5 value verify ways：
Windows user：Download WinMD5Free software to verify file。
Linux user： run md5sum filename .

Creation steps

Ⅰ. USB stick partition
We will create two partitions on USB stick and install OS on the second partition.
Because, Windows doesn’t recognize the second partition. This strategy has extra
protection where the USB inserted in online windows machine carelessly.

1,Boot from Ubuntu CD，select “Try Ubuntu” button, and insert USB stick.
2,Click "Dash Home button"（top-left button）->input "disk"->Click "Disks"，create partition on the USB stick。

Ⅱ. Create persistent Live-USB stick
Click "Dash Home button"（top-left button）->input "creator"->Click "Startup Disk Creator"，（please select "Stored in extra space" option）。

After persistent Live-USB stick creation completion, Boot form the USB stick on a offline PC.
Select “Try Ubuntu” button on welcome screen.

(For Thinkpad PC, press F12 to open the Boot menu during system post.
The shortcut key is various. it may be F12,F2,F10 or ESC.
if it doesn’t works we need look up the computer reference.)

Ⅲ.System settings.
The following steps all run in the terminal window.
1,Change the password of the default user ubuntu (default password is blank)
run

Code:

passwd

2，Disable desktop automatic login

Code:

sudo vi /etc/lightdm/lightdm.conf

Edit content with the following：

Code:

[SeatDefaults]
allow-guest=false
autologin-guest=false
autologin-user=
autologin-user-timeout=0
autologin-session=lightdm-autologin
greeter-show-manual-login=true

3，Disable other terminal automatic login.

Code:

sudo rm /etc/init/tty*.conf

4，Cancel Ubuntu weclome screen when boot.

Code:

sudo vi /media/cdrom/syslinux/syslinux.cfg

Edit content with the following：

Code:

default live
label live
menu label ^Try Ubuntu without installing
kernel /casper/vmlinuz
append noprompt cdrom-detect/try-usb=true persistent file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash --

Ⅳ. Create normal account and encrypted folder

1,Create normal account richard.
2,Login with new account: richard, create encrypted Private folder
run

Code:

ecryptfs-setup-private

3,Change electrum to store wallet data in Private folder by default.
Electrum store wallet data in .electrum folder under user home folder by default.( in
the sample is:/home/richard/.electrum)
run:

Code:

cd ~/Private
mkdir .electrum
cd ..
ln -s ~/Private/.electrum .electrum

Ⅴ Close system network connection

Commonly, the cold wallet computer must be disconnect from network physically.
Unplug network cable and close WIFI switch if available.
In the step, we disconnect network on software layer.
1,Click "Dash Home button"-> input "startup" -> click "Startup Applications"
2,Add startup program： nmcli nm enable false

Ⅵ Offline Install Electrum
1.Login with new user:richard
2.Copy Electrum-1.9.8.zip file to the new user home folder: /home/richard
(we can use another clean USB stick to copy the file)
3.Verify the file
In terminal window，goto the home folder.

Code:

cd ~
md5sum Electrum-1.9.8.zip
0f91f548ba64b1f5776a28b1522f07ec Electrum-1.9.8.zip

Verify the MD5 value to make sure it is the same as the value on official site exactly
4. Install Electrum。

Code:

unzip Electrum-1.9.8.zip

5. Run Electrum

Code:

cd ~/Electrum-1.9.8
python electrum

Completion.

For novice, the pdf document with screenshots is more easier to understand,
The pdf file download url:
https://mega.co.nz/#!DwAQyYLQ!rugqZ4ZciMOUXhdW5bAB6rz5D354c5cymWeJqTZcNoM

Richard Huang
BTC: 194qRKhLATLoYsF6V9ficUXEh9FVsHXqQA

Creative Commons Attribution 3.0
2014-11 Chengdu

[btcshare]

wallet USB sounds nice a wallet!

[tzortz]

Also backup or clone.

[Elwar]

Do not rely too much on a USB being secure.
http://www.wired.com/2014/07/usb-security/

[cryptworld]

I think you should add this truecrypt encryption

[huanghq]

Do not rely too much on a USB being secure.
http://www.wired.com/2014/07/usb-security/

Yes.
To avoid the BAD-USB firmware risk, don't plug the USB stick into untrusted PC.
and don't connect untrusted USB devices (include keyboard,mouse) to your offline wallet computer.

[huanghq]

I think you should add this truecrypt encryption

If you use dedicated PC for cold storage, full filesystem encryption is good.
the performance of full filesystem encryption on USB disk is not well.

[pooya87]

i cannot find the PDF file in the provided link at the bottom of the comment
nevermind  i clicked the complete link after the #

For novice, the pdf document with screenshots is more easier to understand,
The pdf file download url:
https://mega.co.nz/#!DwAQyYLQ!rugqZ4ZciMOUXhdW5bAB6rz5D354c5cymWeJqTZcNoM

also, why did you boot Ubutu from USB? isn't it enough to boot it from the Ubuntu CD?
and about the partition that you created on USB. was it for booting Ubuntu or keeping the installed wallet or both?
i meant can't you just create the partition with Ubonto and keep ONLY the wallet there?

sorry if my questions was newbish

[huanghq]

i cannot find the PDF file in the provided link at the bottom of the comment
nevermind  i clicked the complete link after the #

For novice, the pdf document with screenshots is more easier to understand,
The pdf file download url:
https://mega.co.nz/#!DwAQyYLQ!rugqZ4ZciMOUXhdW5bAB6rz5D354c5cymWeJqTZcNoM

also, why did you boot Ubutu from USB? isn't it enough to boot it from the Ubuntu CD?
and about the partition that you created on USB. was it for booting Ubuntu or keeping the installed wallet or both?
i meant can't you just create the partition with Ubonto and keep ONLY the wallet there?

sorry if my questions was newbish

1， Only boot from live Ubuntu CD, can't store any data when next restart PC.
2, Create 2  partition is just a junior protection. Windows OS can't find the 2nd partition.
    Both Ubuntu and wallet keeps in the 2nd partition.
Yes, if you like, you can skip the usb disk partition steps.

[AdamWhite]

Make sure you also keep paper wallet or other forms of backup, i feel sorry for anyone who only keeps a backup on a USB key. USB keys are unstable and TOTALLY UNSUITABLE for keeping important data long term

many will discover this the hard way...

[huanghq]

Make sure you also keep paper wallet or other forms of backup, i feel sorry for anyone who only keeps a backup on a USB key. USB keys are unstable and TOTALLY UNSUITABLE for keeping important data long term

many will discover this the hard way...

Yes , we need to write down the 12 words Electrm wallet seed on the paper and keep it in safe place.

[HeroCat]

I do not think that USB stick is safe wallet - there can be a lot of problems. For example, there are viruses, that use USB stick. And if you use one Linux OS - you can use only that one Linux OS, so you can not use USB stick in other machines with different OS then.

[pooya87]

@huanghq
thanks a lot for creating this walk-through it was so useful

I do not think that USB stick is safe wallet - there can be a lot of problems. For example, there are viruses, that use USB stick. And if you use one Linux OS - you can use only that one Linux OS, so you can not use USB stick in other machines with different OS then.

i have never head of virus on linux! there is none.
the only risks for using this way are: forgetting your passwords and damaging USB stick physically nothing else comes to my mind
and for preventing these two you can write your seed and/or passwords on a piece of paper and keep it safe

[huanghq]

@huanghq
thanks a lot for creating this walk-through it was so useful

I do not think that USB stick is safe wallet - there can be a lot of problems. For example, there are viruses, that use USB stick. And if you use one Linux OS - you can use only that one Linux OS, so you can not use USB stick in other machines with different OS then.

i have never head of virus on linux! there is none.
the only risks for using this way are: forgetting your passwords and damaging USB stick physically nothing else comes to my mind
and for preventing these two you can write your seed and/or passwords on a piece of paper and keep it safe

The viruses can be wrote on USB device firmware.
So don't use any untrusted USB devices (include keyboard,mouse, charger) on wallet PC or mobile.
and don't plug the USB stick into untrusted PC.
Don't flaunt your funds.

[fearlesscat10]

Will try this.

But why Electrum? Isn't Armory generally better suited for cold wallets?

[siameze]

Do not rely too much on a USB being secure.
http://www.wired.com/2014/07/usb-security/

While I do think this was a very well written tutorial, Elwar has a point in regards to usb security. I saved a copy of your pdf for future reference however.

[LiteCoinGuy]

nice guide but a hardware-wallet is better for a newbie i think   :

https://bitcointalk.org/index.php?topic=899253.0

[bornil267645]

I am not that much of a fan of USB, and it can get affected.

[huanghq]

I am not that much of a fan of USB, and it can get affected.

So, I write a simple application to transfer data through air gap by QR code movies:
flipqr : https://bitcointalk.org/index.php?topic=978033.0

[jeffhuys]

Great guide, will definitely use this in the future. I should really have more backups of my wallets, and I should have a cold wallet as well (paper or something). I don't even trust printers, man. Especially those network-connected ones.