For (3) there are not currently any plans to implement digital certificate features within DHIS2 core - there are many existing solutions which can be integrated with DHIS2 in various ways based on local requirements, as outlined on the Digital Certificates page @Enzo shared.
We have successfully deployed the option 2(DIVOC) in Sri Lanka and currently doing the 4th dose!
Please find a summary of the implementation below.
DHIS2 handles vaccination events capturing via the tracker.
DIVOC is used just as the certificate store(for generating, storing and validating) and everything else is implemented as a sidecar service that runs parallel to the dhis2 instance.
The sidecar service reads directly from the DHIS2 database.
The new service is exposed under /api/custom via the sidecar service and it controls which DHIS2 role can issue or reissue certificates via the sidecar service, checks the eligibility of the vaccine recipients to issue a certificate, communicate with DIVOC service to generate the certificates etc.
Once issued, we send a public URL to the citizen’s email address or phone number(SMS). They can use this URL to download the certificate as a PDF.
Certificate has an embedded QR code that can be used by authorities to validate the authenticity of the certificate(validation is provided by DIVOC)
A modified version of the tracker capture calls this new API endpoint to issue/reissue certificates.
We also provide a dashboard for the admin teams to audit and monitor the progress of the certificate issuance.