This website contains age-restricted materials including nudity and explicit depictions of sexual activity.
By entering, you affirm that you are at least 18 years of age or the age of majority in the jurisdiction you are accessing the website from and you consent to viewing sexually explicit content.
Well, by using a QR code you don’t have to invent your own 2D system, as blackjack and hookers aren’t really necessary.
Just make your own URI protocol, and encode any signature in the link. Bonus if you can register your protocol in Android or IOS, but I don’t know if this is possible.
Apps an indeed register URL schemes with their domain or chosen protocols to open by default on Android.