Wait, why are they using 45 characters to encode 16 bits when you only need 41?
Especially when they could have avoided % and space.
Especially when they could have avoided % and space.
[1]: https://github.com/ehn-dcc-development/hcert-spec/issues/64
Well the reason to care is to avoid QR decoder quirkiness, otherwise you should probably just use the binary encoding.
> I read through some Github issue [1]
According to a comment near they end they were originally going to try to pack everything as a single base 45 bignum, so that half explains it. But not why they'd stick with 45 characters when changing that.