8.0 KiB
How to create encrypted paper backup
Requirements
- Hardened Raspberry Pi 📦
- Adafruit PiTFT monitor (optional)
- macOS computer
Caveats
- When copy/pasting commands that start with
$
, strip out$
as this character is not part of the command - When copy/pasting commands that start with
cat << "EOF"
, select all lines at once (fromcat << "EOF"
toEOF
inclusively) as they are part of the same (single) command
Setup guide
Step 1: log in to Raspberry Pi
Replace 10.0.1.248
with IP of Raspberry Pi.
When asked for passphrase, enter passphrase from step 1.
ssh pi@10.0.1.248 -i ~/.ssh/pi
Step 2 (optional): install Adafruit PiTFT monitor drivers and disable console auto login
Install Adafruit PiTFT monitor drivers
Heads-up: don’t worry about
PITFT Failed to disable unit: Unit file fbcp.service does not exist.
.
Heads-up: when asked to reboot, type
n
and press enter.
$ sudo apt update
$ sudo apt install -y git python3-pip
$ sudo pip3 install --upgrade adafruit-python-shell click==7.0
$ git clone https://github.com/adafruit/Raspberry-Pi-Installer-Scripts.git
$ cd Raspberry-Pi-Installer-Scripts
$ sudo python3 adafruit-pitft.py --display=28c --rotation=90 --install-type=console
Disable console auto login
Heads-up: when asked to reboot, select “No” and press enter.
sudo raspi-config
Select “System Options”, then “Boot / Auto Login”, then “Console” and finally “Finish”.
Step 3: configure keyboard keymap
Heads-up: following instructions are for Raspberry Pi keyboard (US model).
Heads-up: when asked to reboot, select “No” and press enter.
sudo raspi-config
Select “Localisation Options”, then “Keyboard”, then “Generic 105-key PC (intl.)”, then “Other”, then “English (US)”, then “English (US)”, then “The default for the keyboard layout”, then “No compose key” and finally “Finish”.
Step 4: install dependencies
$ sudo apt update
$ sudo apt install -y fim imagemagick zbar-tools
$ pip3 install pillow qrcode --user
$ echo "export GPG_TTY=\"\$(tty)\"" >> ~/.bashrc
$ echo "export PATH=\$PATH:/home/pi/.local/bin" >> ~/.bashrc
$ source ~/.bashrc
Step 5: download bip39.txt (PGP signature, PGP public key)
sudo curl -o /usr/local/sbin/bip39.txt https://sunknudsen.com/static/media/privacy-guides/how-to-create-encrypted-paper-backup/bip39.txt
Step 6: download qr-backup.sh (PGP signature, PGP public key)
sudo curl -o /usr/local/sbin/qr-backup.sh https://sunknudsen.com/static/media/privacy-guides/how-to-create-encrypted-paper-backup/qr-backup.sh
sudo chmod +x /usr/local/sbin/qr-backup.sh
Step 7: download qr-restore.sh (PGP signature, PGP public key)
sudo curl -o /usr/local/sbin/qr-restore.sh https://sunknudsen.com/static/media/privacy-guides/how-to-create-encrypted-paper-backup/qr-restore.sh
sudo chmod +x /usr/local/sbin/qr-restore.sh
Step 8: download qr-clone.sh (PGP signature, PGP public key)
sudo curl -o /usr/local/sbin/qr-clone.sh https://sunknudsen.com/static/media/privacy-guides/how-to-create-encrypted-paper-backup/qr-clone.sh
sudo chmod +x /usr/local/sbin/qr-clone.sh
Step 9: reboot
sudo systemctl reboot
👍
Usage guide
Create encrypted paper backup
Heads-up: use
--bip39
to test secret against BIP39 word list.
$ qr-backup.sh --help
Usage: qr-backup.sh [options]
Options:
--bip39 test secret against BIP39 word list
-h, --help display help for command
$ qr-backup.sh
Format USB flash drive? (y or n)?
y
mkfs.fat 4.1 (2017-01-24)
Type secret and press enter (again)
this is a test yo
-----BEGIN PGP MESSAGE-----
jA0ECQMKmFCBKHBUX8z/0kUBxi8eP7LRqP0WgOF+VgTMYuvix7AMxWR/TRM+zQk/
i9JLr52Odmxv23jEC/KfAUdigAqhs3/GJRtwWuC2IR5NzfBNvXM=
=xkQH
-----END PGP MESSAGE-----
SHA512 hash: 177cc163d89498b859ce06f6f2ac1cd2f9f493b848cdf08746bfb2f4a8bf958ebb45eb70f8f20141c12aa65387ee0545b7c0757cf8d6c808e2fa449fad0e986a
SHA512 short hash: 177cc163
Show SHA512 hash as QR code? (y or n)?
n
Done
The following image is now available on USB flash drive.
Restore encrypted paper backup
Heads-up: use
--word-list
to split secret into word list.
$ qr-restore.sh
Usage: qr-restore.sh [options]
Options:
--word-list split secret into word list
-h, --help display help for command
$ qr-restore.sh
Scan QR code…
-----BEGIN PGP MESSAGE-----
jA0ECQMKmFCBKHBUX8z/0kUBxi8eP7LRqP0WgOF+VgTMYuvix7AMxWR/TRM+zQk/
i9JLr52Odmxv23jEC/KfAUdigAqhs3/GJRtwWuC2IR5NzfBNvXM=
=xkQH
-----END PGP MESSAGE-----
SHA512 hash: 177cc163d89498b859ce06f6f2ac1cd2f9f493b848cdf08746bfb2f4a8bf958ebb45eb70f8f20141c12aa65387ee0545b7c0757cf8d6c808e2fa449fad0e986a
SHA512 short hash: 177cc163
Show secret? (y or n)?
y
gpg: AES256 encrypted data
gpg: encrypted with 1 passphrase
Secret: this is a test yo
Done
Clone encrypted paper backup
$ qr-clone.sh --help
Usage: qr-clone.sh [options]
Options:
-h, --help display help for command
$ qr-clone.sh
Scan QR code…
-----BEGIN PGP MESSAGE-----
jA0ECQMKmFCBKHBUX8z/0kUBxi8eP7LRqP0WgOF+VgTMYuvix7AMxWR/TRM+zQk/
i9JLr52Odmxv23jEC/KfAUdigAqhs3/GJRtwWuC2IR5NzfBNvXM=
=xkQH
-----END PGP MESSAGE-----
SHA512 hash: 177cc163d89498b859ce06f6f2ac1cd2f9f493b848cdf08746bfb2f4a8bf958ebb45eb70f8f20141c12aa65387ee0545b7c0757cf8d6c808e2fa449fad0e986a
SHA512 short hash: 177cc163
Show secret? (y or n)?
y
gpg: AES256 encrypted data
gpg: encrypted with 1 passphrase
Secret: this is a test yo
Done
Backing up…
Format USB flash drive? (y or n)?
y
mkfs.fat 4.1 (2017-01-24)
-----BEGIN PGP MESSAGE-----
jA0ECQMKAWdJZylXXDf/0kUB/rRdX1+5OYVh7iwzM0julwIfDe57slc6LeGeRtDa
KfY4QZkCrseEoZdSZd5mGYQ0ItW9exfBiXN5AU+rbEmzF6VuEWY=
=ul1g
-----END PGP MESSAGE-----
SHA512 hash: 524d8219b17aad59d7cec70f901dfdd449d15f21479740b0111b621cc870e6d82f2f4a0ea8303fb478b24500195325be9c3256d4d5b19700a1cdd1329fc2c71f
SHA512 short hash: 524d8219
Show SHA512 hash as QR code? (y or n)?
n
Done
The following image is now available on USB flash drive.
Secure erase flash drive
$ secure-erase.sh --help
Usage: secure-erase.sh [options]
Options:
--iterations overwrite n times (defauls to 3)
--zero overwrite with zeros to hide secure erase
-h, --help display help for command
$ secure-erase.sh
Secure erase USB flash drive? (y or n)?
y
Erasing… (iteration 1 of 3)
dd: error writing '/dev/sda1': No space left on device
1868+0 records in
1867+0 records out
1957691392 bytes (2.0 GB, 1.8 GiB) copied, 181.888 s, 10.8 MB/s
Erasing… (iteration 2 of 3)
dd: error writing '/dev/sda1': No space left on device
1868+0 records in
1867+0 records out
1957691392 bytes (2.0 GB, 1.8 GiB) copied, 195.606 s, 10.0 MB/s
Erasing… (iteration 3 of 3)
dd: error writing '/dev/sda1': No space left on device
1868+0 records in
1867+0 records out
1957691392 bytes (2.0 GB, 1.8 GiB) copied, 195.558 s, 10.0 MB/s
Done
👍