Not necessarily, depending on how the application is logging it just means the resolution to which you know a birth date is limited by how often the application is run. If i check my email every morning at 8am, and my email app logs my "age bucket", then it can know to a resolution of one day. If i only check my email on Monday mornings, it knows to a resolution of one week, etc...
The size of the age bracket also puts practical limitations on it. There is only one mandated bracket for everyone who's at least 18, preventing that attack on anyone who starts using your software after their 18th birthday. And if a 13 year old signs up it takes three years for you to observe the switch to the >=16,<18 bucket
> And if a 13 year old signs up it takes three years for you to observe the switch to the >=16,<18 bucket
I think this is the big vulnerability in the scheme. This information is easy to track and log, so it is basically equivalent in the giving away the DOB of everybody who is currently under 18 (at least, everybody who uses the system as intended). In the long run that’s everybody.
We could have a discussion about whether or not it would be fine for services to know every user’s DOB, but it is clearly giving away more information than the law intended.
> There is only one mandated bracket for everyone who's at least 18, preventing that attack on anyone who starts using your software after their 18th birthday.
I don’t think that fully recognizes the size of the problem, “using your software” is fuzzy. Companies get bought, identities get correlated, ad services collect and log more information than needed. I think it is better to assume the attacker will have logs of these queries from the start date of a person’s first account.
