Run pdflatex --shell-escape gpgbackup.tex to produce a pdf that you can print and lock away.
In order to recover the key, you will have to scan extract individual QR Codes with names IMGa.png, IMGb.png, IMGc.png and IMGd.png, as given in the name of each figure, then run the recovery commands.
NOTE: The above command WILL leave some artefacts in /tmp which should be removed using the command rm /tmp/IMG*png
PS: Original formula for this gist was from @costrouc.
| \documentclass{article} | |
| \usepackage[a4paper]{geometry} | |
| \usepackage{caption,subcaption} | |
| \usepackage{float} | |
| \usepackage{graphicx} | |
| \usepackage{pgffor} | |
| \def\gpgkey{YourKeyName} | |
| \newcommand\gpgtopng{ | |
| \immediate\write18{gpg --export-secret-key \gpgkey | paperkey --output-type raw | base64 > temp} | |
| \immediate\write18{split temp -n 4 IMG} | |
| \immediate\write18{for f in IMG*; do cat $f | qrencode -o /tmp/$f.png; done} | |
| \immediate\write18{rm IMG* temp} | |
| } | |
| \gpgtopng | |
| \begin{document} | |
| \centering | |
| \begin{figure} | |
| \foreach \i in {a, ..., d} {% | |
| \centering | |
| \begin{subfigure}[p]{0.45\textwidth} | |
| \includegraphics[width=\linewidth]{/tmp/IMGa\i.png} | |
| \caption{ }\label{fig:subfig\i} | |
| \end{subfigure}\quad | |
| } | |
| \end{figure} | |
| To recover run the following command | |
| \begin{verbatim} | |
| for f in IMG*.png; do zbarimg --raw $f | head -c -1 > $f.out ; done | |
| cat *.out | base64 -d | paperkey --pubring ~/.gnupg/pubring.gpg | gpg --import | |
| \end{verbatim} | |
| \end{document} |