That wouldn't really work because the hash key has to be both specific enough to be unique to you and also general enough to cover any incomplete data set that matches you.

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itsyonas 3 days ago | parent | next [-]

It would work in many cases, though not all. You would not hash everything together. Instead, you hash normalized identifiers independently, such as email address, phone number, or physical address. An incoming dataset would only need to match one of these to be excluded.

	▲	monerozcash 2 days ago \| parent [-]
		> physical address Not unique to a person > email address, phone number Also often not unique to a person, although email addresses probably tend to have much longer lifespans as identifiers than phone numbers. If the idea is to have a true opt-out system, it's really really difficult to implement given how these systems work. If you look at the data provided by services like accurint, you'll frequently see the same SSNs used for decades by multiple different individuals, often with IDs from different states with the same name and DoB despite obviously being different people. With how the system works in the US, it can often be impossible for anyone to determine which physical person the SSN was actually originally assigned to. Same obviously applies to other identifiers you suggested, but even the seemingly good ones are not very good at uniquely identifying people.

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monerozcash 3 days ago | parent | prev [-]

You could of course key on things like SSNs, but data brokers wouldn't be very happy about that because there are lots of SSNs tied to multiple different people.

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collingreen 2 days ago | parent [-]

Won't somebody think of the data brokers!?

	▲	JasonADrury 2 days ago \| parent [-]
		The government will, given that they're a fairly integral part of how the US economy. Every single financial institution relies on these data-brokers. U-haul needs data brokers to be able to verify your driver's license, the TSA needs data brokers to let you on a flight without an ID. There are simply countless of reasons for why you wouldn't want to break this system for people who haven't opted in for breakage.