I added four symbols of Reed-Solomon error correction to the end. Means you can have at most two characters lost and you can still get a good read, or whatever. I wanted to be darn sure of a good read before sending keystrokes, and possibly locking a user out.
Here’s a working barcode coming off of it:
So I have been having issues getting the SHA1 to work on the ATTiny, but just about any other board works. That’s what is at the core of the HOTP. And this is precisely the chip I want to be able to use, because it’s small.
For now, I’m going to allow the ATTiny to not work, for now, and drive ahead on other chips that do not cause me bewilderment.
Now to make a USB keyboard emulator that can read it, and power it.
Anyway, here’s the source code: