What is the benefit of using a QR code over just printing and storing the document itself in a human-readable format?
I'm trying to think of when/why I would want to add the extra step of converting to/from QR codes for the documents I keep in my safe, but I'm not coming up with any reasonable use case.
I'm sure I could just be missing the use case(s) the author has in mind, perhaps they should be suggested in the readme.
Edit: Several good examples below, thanks.
> What is the benefit of using a QR code over just printing and storing the document itself in a human-readable format?
Easier reading back. You don't want to be typing your private key in, and while scanning + OCR might be pretty reliable unless you are daft about font and text size choices getting text direct from the QR code on your phone (or direct into a PC/laptop if you have a scanner that perhaps types the content by pretending to be a USB keyboard), feels to me like it would be more convenient.
You can store a 2048-bit RSA private key in standard text form in a QR code, so after scanning to clipboard all you have to do is paste the text into an appropriate file, or again using the scan->HID option that is slightly more direct.
For longer keys you will need multiple QR codes, of course, and a very slightly more convoluted method. I have a couple of keys, SSH private keys and the master key for a keepass store (which is also on a USB token I carry), printed as QR codes stored in a secure place in this manner.
It looks like this tool does not allow for direct input from scanning the QR code(s) in the manner I've just described, as the description says it includes metadata for reassembly of larger data removing the simplest case for small data in favour of making larger data more convenient/robust.
How often do you have to recover a key? I think I did it maybe 3 times in the past 5 years.
I get your point, but a recovery/backup key? Yeah, I really rather have that human-readable, even if it means that I'll likely need a good 30 seconds to type that into wherever I have to type that in.
Yep, if I'm using a physical medium like paper I want to allow for some degradation. Here's a Veritasium video on QR codes: https://youtu.be/w5ebcowAJD8
As someone who made the mistake of printing keys only in human-readable format: ocr software is only so accurate.
So if you have more than a handfull of bytes you may have to actually read it "by hand" to fix errors.
These days I keep the really important keys both as a qr codes and also hex. But the hex is not pleasant to work with.
Personally, I use it for GPG private keys, and importing it again is easier with a barcode scanner than typing the entire file I've printed by hand.
The ability to store binary files comes to mind. PKCS12 certificate files and can't be turned human-readable without risking losing a flag or metadata or whatnot but the format is still widely used.
You could also use this as a basis for a printer+scanner system that exports and imports your system key store(s) automatically without having to risk OCR breaking your import.
Scanning a QR code is also just useful when it comes to entering long random strings. Although I agree that such a tool would do better outputting in plain text as well in case you need to enter it without a phone on hand, I think adding a QR code for loading the files quicker still makes sense.