[dane-pgp]

For countries that already require you to register SIM cards with your government ID, I wouldn't be surprised if one day they require that all phones be biometrically locked to their owner.

When producing a QR code, the signature could include the date that the QR code was generated, and the date that the phone was biometrically linked to the user (signed by a device-specific key in the secure enclave, itself signed by the manufacturer's key).

Venues could then require that you were using a phone that had been soul-bound to you since before the tickets were first available for purchase.

(For the avoidance of doubt, what I'm describing here is the basis of an Orwellian dystopia, not something that I think should ever be implemented.)

[neurostimulant]

What stopping you from taking a screenshot of the qr code and send it to the buyer? The timestamp can be bypassed by sending the screenshot when the buyer is already at the ticket-checking gate.

[krolden]

These apps generate a new code based on the time, etc. Its basically a TOTP password for an event.