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How License-Plate Scanners Are Eroding Our Privacy

80 points| jamesbritt | 12 years ago |popularmechanics.com | reply

91 comments

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[+] alpeb|12 years ago|reply
This reminded me of this pic, trying to sql-inject a license plate system: http://landofthefreeish.com/wp-content/uploads/2010/03/sql-i...
[+] user24|12 years ago|reply
That's more specific SQL than a simple gag would require... story?
[+] Nicholas_C|12 years ago|reply
What is the legality of something like this? If this worked or if it didn't and someone gave a damn it seems like this could fall under attempted destruction of property or something like that. I'm definitely not a lawyer though.
[+] Houshalter|12 years ago|reply
License plate scanners are pretty cool technology-wise. It's amazing machine vision has advanced that much. I was under the impression these were being used to search for specific license plates though. Like a stolen car or the car of a fugitive. I didn't realize they were storing every single license plate recorded into a giant database. That is more concerning.
[+] Amadou|12 years ago|reply
I didn't realize they were storing every single license plate recorded into a giant database. That is more concerning.

The police aren't the only ones doing it.

Data brokers have hooked up with repomen who put scanners on their dashboards and upload every plate they scan to the data broker's databases:

http://www.forbes.com/sites/adamtanner/2013/07/10/data-broke...

US Customs has been handing over plate scan data to insurance companies:

http://www.forbes.com/sites/andygreenberg/2012/08/21/documen...

[+] adolph|12 years ago|reply
It would be an impressive feat of syncing for each license plate monitoring node to receive a constantly updated list of license plates of interest.
[+] A1kmm|12 years ago|reply
The crux of the argument which comes up from the 'apologists' for this type of thing extends from a different understanding of the axioms of privacy to everyone else.

Let p(x) be a proposition that means that doing x is a violation of someone's expectation of privacy.

Some people seem to assume that (not p(x)) and (not p(y)) implies that not p(x union y). In other words, the assumption is that if x is not a violation of someone's expectation of privacy, and doing y is not a violation of someone's expectation of privacy, then doing both x and y is also not a violation of someone's expectation of privacy.

However, the 'mosaic theory' suggests that the above assumption is not valid - doing x and y individually might be perfectly reasonable, but doing both could be a violation of someone's expectation of privacy.

[+] auctiontheory|12 years ago|reply
Here's what the police in my town are doing: http://www.almanacnews.com/news/2013/06/04/the-unfiring-of-a...
[+] yid|12 years ago|reply
From TFA: "...said the Menlo Park police department violated his client's rights during the internal affairs investigation"

I actually support his getting his job back, because it seems to have been found that the police department overstepped their boundaries in their investigation of him. If that is indeed true, then it's imperative that any illegal evidence against him should be discarded.

[+] eliteraspberrie|12 years ago|reply
There is very little which is less private than a license plate. They are explicitly designed to be as public as possible, as they should be.
[+] greenyoda|12 years ago|reply
I think that's totally missing the point of the article. The license plates are being used to track where every person goes over a long period of time, which can uncover some very private information about people, like whether the person is cheating on their spouse, or sees a psychiatrist on a weekly basis.

And yes, you can find this out just by physically following someone wherever they go, but since that's impractical to do on a mass scale, it's not likely to be done for people who aren't targets of specific criminal investigations. License plate scanning collects this personal information indiscriminately about totally innocent people.

And this information is likely to be abused by people in positions of power, just like existing records about people are. I can't count how many times have I've heard about cops getting in trouble for running unauthorized database searches on ex-girlfriends, etc. Detailed data about a person's every movement would be even more tempting to abuse.

[+] schoen|12 years ago|reply
If license plates were meant to be as public as possible, it would be possible for the public to find out who the registered owner of each car was!

In my understanding, license plates were created for two reasons:

* To enforce registration requirements for cars and drivers in order to enforce training standards (for drivers) and safety standards (for the construction and inspection of cars)

* To allow the easier identification of the party responsible for an accident (and maybe for certain other infractions, like speeding, parking violations, or abandoning a vehicle)

That means that other uses to which license plates have been put are a kind of mission creep. Where they harm motorists' privacy, we can reasonably see them as a failure in the design and implementation of the license plate system.

If we had a license plate system that let people responsible for accidents and traffic infractions be identified and that ensured cars were safe without also making it easy to figure out individual people's travel patterns, I'd view that as a strict improvement over the status quo -- and more legitimate, because it wouldn't impose unrelated burdens on motorists.

Right now we're creating and deploying lots of other systems that assign unique identifiers to people and their possessions. Those systems are meant for specific purposes, which their users may see as legitimate, but designing them in the simplest, most obvious way will cause collateral damage to privacy by allowing often invisible kinds of tracking and profiling of people's activities, whereabouts, and relationships. If those uses are not the intended purpose, we should demand more careful designs that end up enabling them.

[+] Amadou|12 years ago|reply
They are explicitly designed to be as public as possible, as they should be.

They were designed in an age in which pervasive video-cameras and back-end databases that never forget were pure science fiction at best.

In effect, the terms of the public's contract with the state regarding license plates have changed. It's time we re-negotiate that contract in light of the new circumstances.

[+] cjaredrun|12 years ago|reply
What about having some sort of UV LED light that would shine above or below your plates so as to obscure any cameras?
[+] toomuchtodo|12 years ago|reply
http://petapixel.com/2012/10/16/nophoto-license-plate-frame-...

"The trick is that that the frame is basically a optically-triggered slave-mode flash unit that’s placed right up to the subject (the license place). A sensor at the top of the frame detects when a flash is fired, which in turn instantly triggers two xenon flashes built into the sides. The powerful flash will turn your license plate into a rectangle of blown-out highlights."

[+] grecy|12 years ago|reply
You can spray your plate with hair spray or clear gloss paint too - the camera flash reflects and the photo is not usable.

It's illegal, of course.

I much prefer the idea of getting a custom plate that's something like 00000O0000 or 1111l11111 etc. depending on the font.

[+] moron4hire|12 years ago|reply
they have been illegal for years. stop light and speeding cameras.
[+] Zoomla|12 years ago|reply
or some polarized glass on top of the license plate (I am just not sure what the angle should be)
[+] psc|12 years ago|reply
What this article doesn't mention is that this data isn't only for cops, anyone should be able to see license plate records. Milage may vary, but since this is government data, something along the lines of a FOIA request should get you huge files with license plates, coordinates, and times. Some police departments may be more stubborn, but under current laws this data should pretty much be public.

For example here's data from Minneapolis (with anonymized license plates): https://github.com/johnschrom/Minneapolis-ALPR-Data

Privacy concerns aside, there's definitely something really cool about so much data.

[+] MikeTLive|12 years ago|reply
historically the use of license plates were fought because of the potential to track the coming and going of american citizens. however, it was decided that it was not possible to do such tracking so they were allowed. the error is that provisions were not made that when such fears were realized the use of such plates should be revoked.
[+] brndnmtthws|12 years ago|reply
Bicycle. Problem solved.
[+] pavel_lishin|12 years ago|reply
The perfect vehicle for someone who has a 60 mile commute in New England during storm weather.
[+] cobrausn|12 years ago|reply
Next up - facial recognition. The article isn't even really about license plates, just about how they are being used.
[+] user24|12 years ago|reply
Bicycle. New problem created.
[+] dmourati|12 years ago|reply
I was going to say just this. I suppose it would be possible for states to require bicycle license plates. I have yet to see that though.
[+] jgoodwin|12 years ago|reply
I think there is a mathematical theory here people should become acquainted with -- differential privacy. So far it has found use in the context of a large data set, e.g. search engine query logs, to try to determine how invasive a statistical summary or release of only partly obfuscated data would be.

Like calculus, it has a sort of epsilon/delta construct -- given a differential privacy concern epsilon, under what circumstances (how tight a bound on delta) do I need to prevent that.

http://en.wikipedia.org/wiki/Differential_privacy

Perhaps this theory could quantify the intuition that while it's ok to snap my license plate now and then (very little differential privacy loss on my part), enough times and it becomes invasive, and dreadfully so.

This puts some teeth into the vague talk about a mosaic theory. The key idea is whether the aggregate information in the data set can triangulate you, to within say 10000 persons (not much privacy invation), or 100 (quite a bit). There seems to be a tipping point around clusters of 100-1000 persons or so, that is the typical size of small organizations or groups of people, such as churches and schools.

Now, as an application: license plates are nearly unique identifiers and the attacker has a database of who's who for all intents and purposes, so it is little different from asking everyone for their ID just because they are on the street. That's illegal by the way, even for the police.

The argument that was formerly deployed here is that using a vehicle on public roadways was a privilege that cost you natural expectation of privacy (non-intrusion) in public places.

The real crux of the issue here is that the public-private tradeoff was once predicated on the individual (the individual atom has protection, because data collection is sparse, so tagging the individual but not the path was meaningful). Now the data collection is dense, and even single particle tracks become visible.

If you think in terms of fluid mechanics, there's a sort of Euler view / Lagrange view here (as there is with tagged dollar particles and tagged wallets or accounts).

That is, tracking individuals and tracking their paths become duals of each other, if the data collection is dense enough. It doesn't matter whether the item tracked is the tagged individual, or the flows and transactions -- either way, complete reconstruction of the system becomes possible.

With any data set, there is a sort of 'phase transition' in its size, where you suddenly can see the underlying trajectories of all the tagged particles. Things that made perfect sense when data collection was sparse, just as allowing the police to jot down you license number and chase you with a bicycle, turn into totalitarian surveillance when the observations become dense enough -- in a way we can quantify in terms of a sudden jump in information gain that goes from nearly complete ignorance of where people are and what they are doing (the former phase), to near complete knowledge of everything. Very much like percolation theory.

[+] Amadou|12 years ago|reply
asking everyone for their ID just because they are on the street. That's illegal by the way, even for the police.

That is not illegal at all. Anyone can ask for ID, including the police. Doesn't mean you have to give it to them. In the case of the police, refusing to show your ID can't be used as cause to arrest you. But they can still ask for it.

[+] jrockway|12 years ago|reply
You already gave up your rights when you agreed to "implied consent". This one isn't even in the Constitution.