[the-dude]

In NL I have to show a QR code to enter certain facilities.

[giantrobot]

Which can be printed on paper?

[015a]

For now. As an example, there are Amazon Prime discounts available at Whole Foods, and this QR code which asserts your membership cannot be printed because it embeds an OTP-like temporal code which changes every 60 seconds.

Any QR code which can be printed, can be copied. There's a vested interest for the operators of these systems to reduce the copyability of these codes (think: vaccine passports). Embedding a temporal code, changing the QR code every few minutes, and invalidating old codes, essentially OTP, is the most straightforward and industry standard way of doing this; it's inevitable.

[the-dude]

This is true. I would need to print twice a week and I don't own a printer.

[growse]

In the UK, you can have it posted to you, so you don't need a printer.

[the-dude]

Does this work for a 'permit to enter' which is only valid 24hrs?

[growse]

Only a CoronaCeck test result certificate is valid for 24 hours. Certificates of vaccination and recovery are valid for much longer (https://coronacheck.nl/en/faq/1-4-hoe-lang-is-mijn-coronabew...).

Are there places which are legally required to only accept test result certificates?

[the-dude]

> Are there places which are legally required to only accept test result certificates?

Not in NL. Why does this matter?

[PeterisP]

For me, elective medical procedures and air travel required a recent (<24h) test result, vaccination was not sufficient.

[vanusa]

Yes.