[MatteoFrigo]

The specifics depend on local regulations, but roughy speaking: the government gives you a document in a standard format (eg MDOC). Your phone stores the document, with cooperation from a secure element that binds the document to the phone. The website you visit verifies the proof. The government gives documents to whatever wallet they want, which may be a special government wallet. They may or may not give the document to Google Wallet.

[coldpie]

Thank you.

> Your phone stores the document, with cooperation from a secure element that binds the document to the phone. The website you visit verifies the proof.

So it does require a "blessed" implementation, and I have to trust Google or Apple to handle my data? I cannot own the document myself and use an open-source client that I trust to provide the proof?

[MatteoFrigo]

It depends on local regulations. As far as I can tell Europe will require some sort of blessing of the wallet. To be clear, governments will develop their own apps and it's not clear that Google will be blessed. We (Google) are giving them the code pro bono to improve privacy.

[coldpie]

Hmm. This introduces a third party to the protocol, right? Specifically the developer of the wallet. So we now have three parties: the user, the wallet developer, and the relying party. Does this zk protocol protect the user's privacy from the wallet developer as well as the relying party?

In other words, does the protocol give the wallet access to information about the relying party? For example, could this wallet that I don't control tell its owner, or the government, that I am using it to access a certain website?

[MatteoFrigo]

Yes, a malicious wallet could leak your information. This is why some governments will insist on using only blessed wallets. However, wallet+zk is strictly better than sending the plaintext MDOC to the relying party. There are no solutions in this space, only tradeoffs, and elected representatives have picked one tradeoff.

[coldpie]

That's too bad :( I wish the protocol had been designed with that in mind. Requiring users to trust proprietary software from Google & Apple to be in complete control over their digital identities is a pretty crummy direction to go in.

[MatteoFrigo]

See https://github.com/eu-digital-identity-wallet/eudi-doc-archi... for a reference to the nuances on all these topics, at least in the context of the European Union. Other locales have different problems and different solutions.

If you think you have a better idea shoot me an email.

[miki123211]

In principle, you could use an open source implementation, but not a user-modifiable implementation.

Nothing stops a government from making their code open source and providing you with reproducible builds. You just won't be able to change the code to do something the government doesn't deem legal.