BCVAX-Android

Vaccine passports in Canada are implemented using the https://smarthealth.cards/ standard. The QR codes are verifiable offline using digital signatures. The app used in BC is open source and available on Github: https://github.com/bcgov/BCVAX-iOS https://github.com/bcgov/BCVAX-Android It works just fine with the device in airplane mode, and does not maintain a record of the QR codes it has verified.

I'm not sure how Quebec's system works, but BC's vaccine cards are based on the SMART Health Card [0] standard. The validation app they've put out is open source [1]. I haven't looked at the validation app's code, but I assume the main reason the have their own app instead of pointing businesses to one of the existing SMART Health Card validators is so they can bundle the public keys used for verifying the QR data wasn't tampered with allowing the app to work offline. The SMART Health Card system does provide a way to download the public keys (I've checked and BC does publish them as expected), but it's probably easier to guarantee offline functionality here. [0] https://smarthealth.cards/index.html [1] https://github.com/bcgov/BCVAX-iOS, https://github.com/bcgov/BCVAX-Android

The BC covid passport verifier apps are open source - https://github.com/bcgov/BCVAX-Android and https://github.com/bcgov/BCVAX-iOS respectively. There is no "user" passport app - the BC Health Gateway website generates a standard (https://smarthealth.cards/) QR code that you can save on phone, or print. The QR codes are signed, but not encrypted - you can dump the contents to verify the payload contains only what's described. Because it's just signature validation of the payload, they can be verified offline.