paSSSphrase: safely store secrets for your successors

My latest GitHub project, paSSSphrase, was inspired by a recent Instructable about electroetching digital assets.


The basic idea is to split a strong passphrase among multiple shares according to Shamir’s Secret Sharing algorithm, then generate an inverted/mirrored image of the shares as QR codes. The image transformations make for an easy electroetching stencil.

So far I haven’t actually done this process for a secret I care about. But I thought electroetching was interesting enough to want to spend a few evenings working on it. I wrote up what I learned from my experience in the project README.

If you try this, let me know! (But don’t send me pictures, please, unless you want to share your secrets with me.)

_Update: The poor man’s version is lines=( $( LC_CTYPE=C </dev/urandom tr -dc ‘[:alnum:]’ | head -c32 | ssss-split -t3 -n5 -Q ) ) ; for line in “${lines[@]}“; do qrencode -o share-${line:0:1}.png $line; done. This version just spits out the shares as individual PNGs that you can print on regular paper. You can verify the results even if you don’t have a QR-code scanner with _zbarimg -raw share-*.png | ssss-combine -t3 -q.