[newdude116]

I don't see many applications for blockchain. The only application is where you don't want to have a trusted central party, be it a company or a government.

I see many start-ups advertising and betting on a blockchain technology by something that could be easier solved with a regular, central database. Are they just bullshitting?

Digital vaccination passports it an example. Why do you need the blockchain? A central government signature/database solves this problem.

[dcolkitt]

For vaccination passports, I don’t think you even need a database. Public key signatures work fine. “John Smith is officially vaccinated. Love, Cook County Health Department”. No persistent service even necessary. John can just keep that QR code on his phone.

Blockchain or trusted database authority is only necessary when there’s the risk of double spend. Like I try to sell my house to two different people at the same time. With vaccine passports there’s no risk. Either you’re vaccinated or not.

[yrro]

You need a service that verifiers can query to determine if the signature has been revoked too...

[srmarm]

That's the bit that gets me confused, with cryptocurrencies there is a clear link between the computer processing and the 'thing' you're representing (i.e crypto hashes).

With say a digital vaccination passport the 'thing' you're wanting to prove is that someone is vaccinated and the interface between the blockchain and the real world still requires a trusted central party(s) - whoever certifies the efficacy and safety of the vaccine, that the batch is legit and that it was actually administered competently and to the person in this case.

As with many of these applications there doesn't seem to be an existing problem with a trusted central party or immutability to solve