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How does making an inference about someone's income, sex, or location violate privacy expectations? Let's say "you speak Luxembourgish and ask where you can bu

How does making an inference about someone's income, sex, or location violate privacy expectations? Let's say "you speak Luxembourgish and ask where you can buy a Mercedes for driving your kids to school" You think it violates your privacy that I might be able to guess where you live, your gender, and your income from that? Did I miss when the world made Bayes theorem illegal?

Pannoniae 3y ago
It depends. Just like it's legal to deposit money into a bank (a legal activity) but it's illegal to structure (a series of legal actions with a specific criminal intent). Applying Bayes' theorem isn't illegal but making interference from other public information then de-anonymising other data based on cross-matching is an entirely different act, regulated by privacy laws. Privacy isn't only about the method, it's also about scale and intent. See CCTV which can individually be dumped the footage from and rewatched to identify criminals vs. live feed surveillance with AI face detection to track everyone 24/7. Same data used but very different intents and outcomes.
- cbsmith 3y ago
  > Privacy isn't only about the method, it's also about scale and intent. I'm with you about the intent, but I don't follow the scale argument. It's not like it isn't a privacy violation if you only do it to one person.
  - Pannoniae 3y ago
    yes, it is, but if you only cross-match data from a single person, that's called conducting a (private) investigation, which is regularly done, that's absolutely legal... However, it changes when you do that in an automated way, en masse, both ethically and legally.
    - cbsmith 3y ago
      The "automated way" is just a matter of perspective. What matters is that the more efficiently you can do it, the fewer resources you need to devote to "investigate" anyone. That can certainly create ethical quandaries. I don't follow how it creates a legal one. AFAIK, the boundaries on privacy laws tend to be tied to access & consent, not scale. Scale just changes the size of the violation. Can you give me an example of a privacy law where the legal line is drawn around scale?
    - chii 3y ago
      > en masse, both ethically and legally. I think only problematic ethically. From what i can see, there can't be anything illegal about collecting publicly available information and using any algorithm to analyse and deduce information from it.
      - rperez333 3y ago
        The GDPR in Europe doesn’t allow you to use publicly available information without explicit user consent, especially if involves personal data. Even doing some Google Analytics can in theory result in large fines.
        cbsmith 3y ago
        The GDPR is really complicated. There's plenty of publicly available information you can use without explicit user consent. What's true is that many of GDPR's rules, particularly the disclosure of data sources and erasure requests, don't get an exemption just because the data is publicly available. For example, while they can't just divulge my name & age in the news, the captions under pictures in news articles can often still have people's names & ages under them without explicit user consent. Tabloids would likely cease to exist if it were any other way. ;-)
        pixl97 3y ago
        Actors living in other countries with no contacts to Europe don't give two shits about GDPR. If I'm a hacker looking at tracking down particular users and committing phishing/watering hole attacks all the laws on the planet really don't matter. What does matter is the data you leak online and the tools I can use to process it.
ReactiveJelly 3y ago
Your birthday and zip code is almost enough to identify you. Every bit of entropy counts
- cbsmith 3y ago
  Your point stands, but the comment is misleading. The claim is birthdate+zip+gender could uniquely identify 87% of the US population, and there are respectable studies to back this stuff up (https://groups.csail.mit.edu/mac/classes/6.805/articles/privacy/sweeney-thesis-draft.pdf https://groups.csail.mit.edu/mac/classes/6.805/articles/priv...). There aren't a lot of days where there's only one person celebrating their birthday in an entire zip code. Even factoring in birth year and gender, I struggle with this a bit, because I know that in densely populated areas of the country, where more and more of the population lives (upwards of 80% of the US lives in urban environments), you'll find multiple babies with the same gender being born in the same hospital on any given day... and there are often multiple hospitals servicing the same zip code! Despite all this, your point still stands: it doesn't take much data to deanonymize someone.
kromem 3y ago
I think it's more the opposite that needs to change, in that people should realize that most information they make public can reveal more than they think. I remember when store algorithms were identifying a teenage girl was pregnant before her family knew and offering her discounts on maternity stuff. That anecdote was from over a decade ago. Today average users are worried their phone is listening to them because something in a conversation comes up in a targeted ad, clearly worried about the idea of "private voice data" being compromised, but somehow less weirded out by the fact that the end result is possible without listening to anything. Our expectations of privacy in relation to our data need to change with the times, and research like this helps that slightly, though to be honest the real picture of what can be discerned from data isn't reflected in public research but is enshrined in private practice, and having seen some of that side of things this paper's 'discovery' is a giant yawn. People should begin to prepare for a future where your anonymous activities online (esp images and text) are cross correlated to your public activities trivially by any interested party. And where your deep dark secrets aren't so secret or where truth and lies can reasonably be revealed as such. Cheating in a relationship? Are you unique enough that a multimodal model fed all public social media data can't identify matching patterns in online behavior changes from early in a relationship to later for profiles where the SO later posted about infidelity and compare to your activity? When switching from scented candles to unscented can tell a store's algorithm with access to broad data that you are pregnant before you've told anyone, we really can't yet imagine just what much larger models trained on much more massive data may yet reveal in the smallest actions and nuances.

Pannoniae 3y ago

It depends. Just like it's legal to deposit money into a bank (a legal activity) but it's illegal to structure (a series of legal actions with a specific criminal intent). Applying Bayes' theorem isn't illegal but making interference from other public information then de-anonymising other data based on cross-matching is an entirely different act, regulated by privacy laws. Privacy isn't only about the method, it's also about scale and intent. See CCTV which can individually be dumped the footage from and rewatched to identify criminals vs. live feed surveillance with AI face detection to track everyone 24/7. Same data used but very different intents and outcomes.

cbsmith 3y ago
> Privacy isn't only about the method, it's also about scale and intent. I'm with you about the intent, but I don't follow the scale argument. It's not like it isn't a privacy violation if you only do it to one person.
- Pannoniae 3y ago
  yes, it is, but if you only cross-match data from a single person, that's called conducting a (private) investigation, which is regularly done, that's absolutely legal... However, it changes when you do that in an automated way, en masse, both ethically and legally.
  - cbsmith 3y ago
    The "automated way" is just a matter of perspective. What matters is that the more efficiently you can do it, the fewer resources you need to devote to "investigate" anyone. That can certainly create ethical quandaries. I don't follow how it creates a legal one. AFAIK, the boundaries on privacy laws tend to be tied to access & consent, not scale. Scale just changes the size of the violation. Can you give me an example of a privacy law where the legal line is drawn around scale?
  - chii 3y ago
    > en masse, both ethically and legally. I think only problematic ethically. From what i can see, there can't be anything illegal about collecting publicly available information and using any algorithm to analyse and deduce information from it.
    - rperez333 3y ago
      The GDPR in Europe doesn’t allow you to use publicly available information without explicit user consent, especially if involves personal data. Even doing some Google Analytics can in theory result in large fines.
      - cbsmith 3y ago
        The GDPR is really complicated. There's plenty of publicly available information you can use without explicit user consent. What's true is that many of GDPR's rules, particularly the disclosure of data sources and erasure requests, don't get an exemption just because the data is publicly available. For example, while they can't just divulge my name & age in the news, the captions under pictures in news articles can often still have people's names & ages under them without explicit user consent. Tabloids would likely cease to exist if it were any other way. ;-)
      - pixl97 3y ago
        Actors living in other countries with no contacts to Europe don't give two shits about GDPR. If I'm a hacker looking at tracking down particular users and committing phishing/watering hole attacks all the laws on the planet really don't matter. What does matter is the data you leak online and the tools I can use to process it.

ReactiveJelly 3y ago

Your birthday and zip code is almost enough to identify you. Every bit of entropy counts

cbsmith 3y ago
Your point stands, but the comment is misleading. The claim is birthdate+zip+gender could uniquely identify 87% of the US population, and there are respectable studies to back this stuff up (https://groups.csail.mit.edu/mac/classes/6.805/articles/privacy/sweeney-thesis-draft.pdf https://groups.csail.mit.edu/mac/classes/6.805/articles/priv...). There aren't a lot of days where there's only one person celebrating their birthday in an entire zip code. Even factoring in birth year and gender, I struggle with this a bit, because I know that in densely populated areas of the country, where more and more of the population lives (upwards of 80% of the US lives in urban environments), you'll find multiple babies with the same gender being born in the same hospital on any given day... and there are often multiple hospitals servicing the same zip code! Despite all this, your point still stands: it doesn't take much data to deanonymize someone.

kromem 3y ago

I think it's more the opposite that needs to change, in that people should realize that most information they make public can reveal more than they think. I remember when store algorithms were identifying a teenage girl was pregnant before her family knew and offering her discounts on maternity stuff. That anecdote was from over a decade ago. Today average users are worried their phone is listening to them because something in a conversation comes up in a targeted ad, clearly worried about the idea of "private voice data" being compromised, but somehow less weirded out by the fact that the end result is possible without listening to anything. Our expectations of privacy in relation to our data need to change with the times, and research like this helps that slightly, though to be honest the real picture of what can be discerned from data isn't reflected in public research but is enshrined in private practice, and having seen some of that side of things this paper's 'discovery' is a giant yawn. People should begin to prepare for a future where your anonymous activities online (esp images and text) are cross correlated to your public activities trivially by any interested party. And where your deep dark secrets aren't so secret or where truth and lies can reasonably be revealed as such. Cheating in a relationship? Are you unique enough that a multimodal model fed all public social media data can't identify matching patterns in online behavior changes from early in a relationship to later for profiles where the SO later posted about infidelity and compare to your activity? When switching from scented candles to unscented can tell a store's algorithm with access to broad data that you are pregnant before you've told anyone, we really can't yet imagine just what much larger models trained on much more massive data may yet reveal in the smallest actions and nuances.