You are mixing things up, and EU abbreviations do not help.
Many countries in EU already have electronic identity documents and delegate authentication to mobile apps one way or another.
eID or mobile identity application operating over QR codes and used to log into websites and apps is a commodity here.
This has nothing to do with age verification.
I’m not sure what you are saying I am mixing up.
The article links to the source code repository here:
https://github.com/eu-digital-identity-wallet/av-app-android...
That links to the tech spec:
> The solution leverages the existing eIDAS infrastructure, including eIDAS nodes and the trust framework for trusted services, to ensure a high level of security and reliability. By aligning with the technical architecture of the EU Digital Identity Wallet ARF, the solution delivers secure, reusable, and interoperable proofs of age.
> The solution enables users to present their Proof of Age attestation to Relying Parties, primarily for online use cases. The system is optimised for secure and privacy-preserving online presentation, allowing users to prove their eligibility without disclosing unnecessary personal information.
— https://github.com/eu-digital-identity-wallet/av-doc-technic...
Annex A includes details on the ZKP:
> AVI SHOULD support the generation of Zero-Knowledge Proofs using the solution detailed in: "Matteo Frigo and abhi shelat, Anonymous credentials from ECDSA, Cryptology ePrint Archive, Paper 2024/2010, 2024, available at https://eprint.iacr.org/2024/2010".
— https://github.com/eu-digital-identity-wallet/av-doc-technic...
And the linked paper:
> Anonymous digital credentials allow a user to prove possession of an attribute that has been asserted by an identity issuer without revealing any extra information about themselves. For example, a user who has received a digital passport credential can prove their “age is ” without revealing any other attributes such as their name or date of birth.
— https://eprint.iacr.org/2024/2010