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Algorithm can pick out almost any American in supposedly anonymized databases

nytimes.com

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Re: Algorithm can pick out almost any American in supposedly anonymized databases

#31
post #24

Earlier quoted context omitted.

Pseudonymization already refers to reference by pseudonym. Pseudonimization is bad terminology in that it's indistinct from the above, to the point that parent has already mixed the two up while in the process of recommending it. And it'd be worse verbally. "Pseudo-anonymization" could work, but something like "breakable anonymization" or "partial anonymization" might be better in that it's more obvious to a reader a…

Its not partial. Its pseudo.

[deleted]

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#32
post #14

I'm a programmer in the GP data analysis world. We use the term 'pseudonymization' for this kind of data. 'Anonymization' is used solely to refer to, say, 'the sum total of diabetes patients this practice has' (that would be anonymous patient data; it would not be anonymous relative to the GP office this refers to): Aggregated data that can no longer be reduced to a single individual at all. The term raises questions…

It doesn't roll off the tongue, perhaps pseudo-anonymization is enough.

I would suggest "denonymization", implying that the "names" (i.e. identifiable information) were removed. As opposed to anonymous data, which presumably never had any to start with, like the example mentioned by the GP.

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#33
post #27
post #22

Earlier quoted context omitted.

Yes, in the sense that the output of a differentially private protocol has mathematical guarantees against re-identification, regardless of the computational power or side information an adversary has. There are caveats. The exact strength of the privacy guarantee depends on the parameters you use and the number of computations you do, so simply saying "we use a differentially private algorithm" doesn't guarantee pri…

do you have some examples?

Of a differentially private algorithm? Frank McSherry (one of the authors of the original differential privacy paper) has a nice blog post introducing the idea and giving many examples with code [1].

Or even more briefly, if you want to know how many people in your database have characteristic X, you can compute that number and add Laplace(1/epsilon) noise [2] and output the result. That's epsilon-differentially private. In general, if you're computing a statistic that has sensitivity s (one person can change the statistic by at most s), then adding Laplace(s/epsilon) noise to the statistic makes it epsilon-differentially private (see e.g. Theorem 3.6 here [3]). The intuition is that, by scaling the added noise to the sensitivity, you cover up the presence or absence of any one individual.

[1] https://github.com/frankmcsherry/blog/blob/master/posts/2016...

[2] https://en.wikipedia.org/wiki/Laplace_distribution

[3] http://cis.upenn.edu/~aaroth/privacybook.html

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#34
post #6

The article title misses a bit of nuance from the paper which is specifically talking about re-identification. e.g from the paper: "We show that, as a male born on July 31, 1945 and living in Cambridge (02138), the information used by Latanya Sweeney at the time, William Weld was unique with a 58% likelihood (ξx = 0.58 and κx = 0.77), meaning that Latanya Sweeney’s re-identification had 77% chances of being correct.…

What accounts for that remaining 2‰ of uncertainty?

Good question. I'd also assume that re-identification chances would always be of the form 100/k (k being the integer number of people who fit the bill)

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#35

If people tell you they're collecting data for statistical purposes, then one of three things: 1. They should deliberately introduce noise into the raw data. Nazis with the raw census data can spend all month trying to find the two 40-something Jews that data says live on this island of 8400 people, but they were just noise. Or were they? No way to know. 2. Bucket everything and discard all raw data immediately. This…

> They shouldn't collect _anything_ personally identifiable

Why not just ensure that any personally identifiable data is properly bucketed, and discarded if it is too strongly identifiable. If you are storing someone's height, age, and gender, you can just increase the bucket size for those fields until every combination of identifiable fields occurs several times in the dataset. If there are always a few different records with well distributed values for every combination of identifiable fields, you can't infer anything about an individual based on which buckets they fall into.

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#36
post #12
post #8

Earlier quoted context omitted.

Nazis used the census because it was there. Were it not, they would have just went house to house - which they then regularly did anyway. The antidote of oppression is not the Index statisticum prohibitorum, but quite the opposite, education, and in particular educating about how different each and every one of us is, and yet it doesn't take much to get along well.

Today's Nazis would probably use machine learning to identify "characteristically Jewish facial features". (Or, of course, simply pass a law that entitles them to deport or hold indefinitely anyone who can't prove they're a real Ayrian with only the papers they have on them at the time)

Probably the latter, considering any sort of genetic or scientific testing that was reasonably accurate at identifying people with Jewish ancestry would also implicate much of German high command (including Hitler).

Remember; fascists don't believe in things because they are true, but because they are a means to an end. Their ultimate goal is authoritarian control, and an administrative mechanism is far more effective toward that goal than a scientific one.

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#37
If they can pick out individuals from the data, then the data is not anonymized. Sure they may have unassociated data spread across unassociated records, but if an algorithm can pick it out, then so could a human (though way more effort). That for me is not anonymized data.

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#38
post #14

I'm a programmer in the GP data analysis world. We use the term 'pseudonymization' for this kind of data. 'Anonymization' is used solely to refer to, say, 'the sum total of diabetes patients this practice has' (that would be anonymous patient data; it would not be anonymous relative to the GP office this refers to): Aggregated data that can no longer be reduced to a single individual at all. The term raises questions…

It doesn't roll off the tongue, perhaps pseudo-anonymization is enough.

Just joking, but how about 'nonymisation' or 'non-nonimysation'

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#39
post #24
post #14

Earlier quoted context omitted.

It doesn't roll off the tongue, perhaps pseudo-anonymization is enough.

Pseudonymization already refers to reference by pseudonym. Pseudonimization is bad terminology in that it's indistinct from the above, to the point that parent has already mixed the two up while in the process of recommending it. And it'd be worse verbally. "Pseudo-anonymization" could work, but something like "breakable anonymization" or "partial anonymization" might be better in that it's more obvious to a reader a…

'Pseudononymization' is how my brain read it. It's a fairly self-explanatory portmanteau with little chance of confusion on the root.

Re: Algorithm can pick out almost any American in supposedly anonymized databases

#40
post #14

I'm a programmer in the GP data analysis world. We use the term 'pseudonymization' for this kind of data. 'Anonymization' is used solely to refer to, say, 'the sum total of diabetes patients this practice has' (that would be anonymous patient data; it would not be anonymous relative to the GP office this refers to): Aggregated data that can no longer be reduced to a single individual at all. The term raises questions…

It doesn't roll off the tongue, perhaps pseudo-anonymization is enough.

True, maybe call it "redacted with a highlighting pen" as appears to get the same results.
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