Today I learned about JAB code, a two-dimensional multi-colour bar code. JAB code works similar to a QR code but due to the use of different colours it achieves a higher data density. It aims to be used on analogue document to sign those digitally and provide a small JAB code for everyone to verify. It’s certified by the German Federal Office for Information Security (better known as BSI) and an implementation is available under LGPL.
I came across that during a conversation about storing small data backups in QR-codes. And while I see the use-case on some documents, I wouldn’t use it for archiving purposes. Due to the use of colours it’s drastically harder to recover after a long time and also subject to colour shifts of the paper. But for the purpose it’s certified for, it’s for sure a good fit.