[snackbroken]

If there's no information provided beyond proof-of-age, what's stopping my friend's 18 year old brother from lending his ID to every 14 year old at school? IRL that's negated by the liquor store clerk looking at the kid who is obviously underage and seeing that his face doesn't match the borrowed card he just nervously presented.

[Mashimo]

> what's stopping my friend's 18 year old brother from lending his ID to every 14 year old at school?

MitID is 2fa. You log in with username, then you have to open the app, enter password or scan biometric, then scan the QR code of the screen* and you are logged in.

He would need to be next to you every time you log in. I think that is too high friction to make it feasible on large scale.

* Assuming you open the website on the Desktop, and MitID on phone. If both on phone, skip this step.

[marcta]

If people have to go through OS auth flow each time they open a website, that will drive everyone mad. One of the key motivators for politicians is not making everyone mad, so the polls don't drop.

Also, I reckon most children know the password for their parent's phone or computer, and many more will find out if there is a highly motivational factor for doing so. How many exhausted parents just toss their phone to their child to stop them whining?

I suppose it could be a biometric sign-in with facial recognition or fingerprint, but again, that's a tonne of friction for the whole web.

[Mashimo]

Most people use biometric for MitID, but yes you can set up pin login. Hopefully not the same as your phone login :D

It's already the single sign on for government websites, banking, healthcare, digital post, insurance, law (sign contracts) etc.

Shit man, you can get divorced through that. I really hope most parents don't give their kids access to it.

[Ajedi32]

That's how the user interface works. What is it doing at the protocol level? What stops someone from building a service that mints anonymous verification codes on a massive scale and distributes them to anyone who asks? Maybe with the user interface being an app kids can download to scan any QR code and pass verification.

[Mashimo]

I don't know. I would assume the account gets blocked if you do it on a larger scale, so you have to rotate account, which gets expensive fast as it's not easy to steal them?

[snackbroken]

> He would need to be next to you every time you log in.

Or you can just text him a screenshot of the QR code. You could probably even automate this.

[Mashimo]

No, the QR code is changing every couple of seconds.

~Maybe~ you can video call, but again it's adding so much friction. Nothing is 100% secure.

[snackbroken]

The automated attack setup I'm envisioning is something like: 18 year old buys a cheapo laptop + phone and connects the two over ADB or some purpose built automation app (think appium). 18 year old puts the phone on a tripod pointed at the laptop screen. 14 year olds at school pay $10 a year for use of the service and install a browser extension that forwards the QR codes from whichever service they wanna use to the 18 year old's computer. Changing every couple of seconds is not an issue here, they all live in the same city and have <10ms ping.

The only high friction part of this is that someone needs to write the software for it, but that doesn't seem like all that difficult of a project and open source solutions are likely to appear within weeks of social media requiring it. If there really is no information shared with the other party beyond "yup, user is over the age of maturity" you could even run this as a free public TOR service without fear of ever getting caught.

[Mashimo]

Mhh, but then the Danish Agency for Digitisation will see that the 18 year old does a lot of age request on all day and night long. And block his account. And then he can't use his own banking, health, postal apps.

High risk, low reward.

If he throttles request to stay under a threshold, if the agency knows about it service they could use it and see which account does age requests at the same time.

[snackbroken]

Ah, so it does leak your identity through the timing side channel. In other words, your anonymity is only dependent on the govt not coordinating with service providers to de-anonymize users. I assumed the 2fa app just held cryptographic keys and did some 0kp magic to show that the cert belongs to a government-attested adult. Phoning home all the time makes it trivial for the government to abuse people's privacy; they can just compel service providers to provide logs of logins.