The "hcert" string is base64 encoded, you can decode that to see the json payload with your personal details, pretty much what's printed on the certificate.
Can get all the info by decoding the "main" base64 encoded string. The hsa256 inside the qr code also seems to be a base64 encoded string. I can get the hex hsa256 string from it eg D4A60EBF3029D6D9869864DD1C4B0E0D0EB56AA5477F700E4468CB0C47F9F09C
It is 256 bits long.
But how is the hsa256 inside the qr code calculated from the "payload" and the "public key"?
There can be a trillion ways to try and calculate it....fact is, it has to be able to work off line. Image you and your family go out to dinner at a restaurant and the DOH database is off line. Surely they will not show away everyone wanting to visit the restaurant because DOH is off line? There must be a way to verify the authenticity of the certificate when DOH database is off line. The only way is to calculate the sha256 from the payload (or part of it for eg using ID and certificate number) and compare it with the sha256 inside the qr code. Anyone that managed to crack it ie how to calculate the sha256 from the info inside the qr code?