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WiFi Routers Used to Produce 3D Images of Humans (vpnoverview.com)
598 points by bubblehack3r on Jan 22, 2023 | hide | past | favorite | 195 comments



> This proof-of-concept would be a breakthrough for healthcare, security, gaming (VR), and a host of other industries.

Similar capability is scheduled for new consumer routers in 2024 via Wi-Fi 7 Sensing / IEEE 802.11bf. Hundreds of previous papers include terms like these:

  human-to-human interaction recognition
  device-free human activity recognition
  occupant activity recognition in smart offices
  emotion sensing via wireless channel data
  CSI learning for gait biometric sensing
  sleep monitoring from afar 
  human breath status via commodity wifi
  device-free crowd sensing
Earlier discussion: https://news.ycombinator.com/item?id=34423395

Sample code exists for ESP32 WROOM, https://wrlab.github.io/Wi-ESP/ and Intel 5300, https://dhalperi.github.io/linux-80211n-csitool/


> Similar capability is scheduled for new consumer routers in 2024 via Wi-Fi 7 Sensing / IEEE 802.11bf.

Reminds me somewhat of a joke I recently saw posted somewhere in social media by a greybeard Unix sysadmin. In a discussion related new consumer grade IOT technology.

"The newest piece of technology I have in my house is an HP Laserjet 4, and I keep a revolver ready to shoot it if it ever makes an unexpected noise"

On a more serious note, however, I see a real serious problem with having consumer/residential wifi routers that can attempt to track people or movement around a house and have the default-on, built in capability to make themselves centrally manageable by some form of persistent internet-based connection-over-TLS link to their manufacturer. Same general ideas as Meraki or other.

Who wants to bet that the manufacturers of these things leave this capability turned on by default AND submitting data through its "cloud management" feature persistently for as long as the device is powered on and has a viable default route/gateway to the internet?

Who wants to bet that in 5-7 years we're seeing problems with these things submitting data sets of peoples' movement around a house into some database run by a vendor that then suffers a major data breach?


That joke is one of the all-time top /r/ProgrammerHumor posts:

https://old.reddit.com/r/ProgrammerHumor/comments/aloi5v/pro...


As you said, I can't imagine how this will not go wrong.


> Earlier discussion: https://news.ycombinator.com/item?id=34423395

The top comment [0] on this has:

> Counter-measures: https://news.ycombinator.com/item?id=27121918#27133079

but I don't understand the setup here. If you have the capability to run custom firmware on your router then don't you not need this countermeasure, since you can be confident your router isn't doing this wireframing anyway? Or is it saying that a passive bystander who is not connected to your network can infer the wireframes as well? That seems unlikely to me?

[0]: https://news.ycombinator.com/item?id=34424242


> passive bystander who is not connected to your network can infer the wireframes as well?

Yes, this can be done with a custom client monitoring existing routers today.

A bystander can also use their own router (2.4Ghz passes through most walls) to make inferences about human activity inside your building.


Then the countermeasure does nothing since you can't run your firmware on their router?


This was just one tiny EU research project with limited funding, which was focused only on passive attacks, e.g. a receiver with custom firmware can make inferences from existing Wi-Fi routers. Their research was looking for a way to modify the default behavior of Wi-Fi transmitters to reduce leakage of location information. If this was the default behavior (e.g. via some combination of IEEE standard and regulation), then active attackers could be easily identified.

https://ans.unibs.it/projects/csi-murder/

> this paper addressed passive attacks, where the attacker controls only a receiver, but exploits the normal Wi-Fi traffic. In this case, the only useful traffic for the attacker comes from transmitters that are perfectly fixed and whose position is well known and stable, so that the NN can be trained in advance, thus the obfuscator needs to be installed only in APs or similar ‘infrastructure’ devices. Active attacks, where the attacker controls both the transmitter and the receiver are another very interesting research area, where, however, privacy protection cannot be based on randomization at the transmitter.

More research and funding is needed.


Correct, this 'countermeasure' is for a fantasy world in which it's easier to compromise your router than set up a couple clients and a router nearby.

Also, realistically, wi-fi isn't the boogeyman here, even though the person you're replying to has been doom-posting about it for years - UWB and various other tech is going to make detecting location and movement from RF frequency fairly trivial.


> compromise your router

No compromise needed. This was one research project looking at the current world where your existing router is happily beaming location information out of your home, which can be read by an attacker with a passive receiver. If an attacker is forced to use their own transmitter, that can potentially be detected.

> wi-fi isn't the bogeyman here

Wi-Fi is the lowest cost modern application of ancient doppler imaging radar that has been around for decades. There is code for ESP32 devices, https://wrlab.github.io/Wi-ESP/. Many years ago, through-the-wall surveillance was primarily used by military and law enforcement with devices costing thousands of dollars. How many people are aware that the capability is now available for $20?


I'm not sure that's accurate. The article suggests they used three routers, and mention 'interference'. I think you'd perhaps need to be more than a 'bystander' to be able to set up a triangle of WiFi routers around someone's home.

Not impossible, of course, but by that point, no longer really a 'bystander'.


Depends on the adversary's objective. The DensePose paper is only one of hundreds of papers on Wi-Fi Sensing for different activities, over ~10 years of funded research, https://news.ycombinator.com/item?id=34485816. E.g. keystroke recognition can be done with a single passive receiver, https://news.ycombinator.com/item?id=34485613

Some research is less dependent on the training environment, https://techxplore.com/news/2021-11-winect-tracks-3d-human-p...

> wireless sensing systems .. mostly rely on models that were pre-trained on a fixed set of known activities, thus they can only classify a limited number of human poses or movements .. our system uses signal processing techniques to separate the Wi-Fi signals reflected from each moving limb and track the trajectory of each limb .. Winect could track free-form human activities with centimeter-level accuracy in a variety of challenging environments and scenarios.

Dec 2022 survey paper categorized recent research on wireless device-free human sensing, https://dl.acm.org/doi/10.1145/3530682

> WDHS systems involve three primary sensing task types. The first type, behavior recognition .. second type is movement tracking .. The third type, user identification, leverages the unique features in behaviors to identify who performs the movements .. we believe that more context-aware multi-modal systems will be proposed to handle the complex sensing tasks in real life.


I read it as three WiFi modules .. such as the three contained in the WIFI router mentioned.


Good shout. I checked the actual paper (here: https://arxiv.org/pdf/2301.00250.pdf, link in the article is broken), and seems you would need multiple routers:

> [...] three WiFi transmitters and three aligned receivers [...]. It should be noted that many WiFi routers, such as TP-Link AC1750, come with 3 antennas, so our method only requires 2 of these routers.

So basically, one on each side of the subject, one to transmit the signal, the other to receive, and then you can work out the interference pattern. It may be possible to do the same with the transmitters and receivers on the same physical device by measuring the reflected signal, but that doesn't seem to be what they were testing.

It seems that the person needs to be between the transmitter and receiver, so I'm not even sure if triangulation would work, although figure 2 implies that you need the 'line of sight' between the routers to be blocked (three 'transmitter' routers and three 'receiver' routers).


> (three 'transmitter' routers and three 'receiver' routers).

Three Tx antennas and three Rx antennas.

You need 3 of them to make a 3d point, otherwise you would have 2d/1d only. Even 1cm difference between antennas placement is more than enough.

> It seems that the person needs to be between the transmitter and receiver

You receive the direct signal earlier than the reflected one. If you find a way to capture both/only reflections then you can do it without LoS and consequently from only one device (though you would still need at least 3 Tx/Rx pairs.)


> Or is it saying that a passive bystander who is not connected to your network can infer the wireframes as well? That seems unlikely to me?

Also known as passive radar


It seems that it's for installing on a station device I guess?


Time to cover walls with tinfoil? :)


I've actually seen people doing this. I wish I had one too. In few decades we'll have Faradey chambers for rent on per hour basis, just like music studios nowadays.


For smaller rooms with good HVAC ventilation for fresh air, EMF reduction can be achieved with removable clamping ZipWall/FastCap poles to support grounded aluminum radiant barrier on walls, roof & floor. E.g. Attic Foil has white vinyl on one side and conductive foil on the other side, about $0.25/sq ft. Matching tape for joints.

To frame the shielded room-within-a-room, cheaper alternatives to ZipWall/FastCap are PVC furniture pipe, electric metallic tube (EMT) conduit or 2x4 pine. Doorway can be shielded with radiant barrier and RE-U-ZIP magnetic entry strip for a reclosable opening. Bonus side effect is thermal insulation.

Transparent RF shielding for windows is more expensive ($4/sq ft), https://safelivingtechnologies.com/signal-protect/.

Use air quality and EMF meters to validate the design and monitor ongoing effectiveness.


Even pre-WiFi 7, there are companies such as Cognitive who allow you to detect motion (as well as occupant activity, etc.). I implemented such a system at my previous company which sold Wi-Fi.


Yes, some vendors have shipped their own implementations. There's also custom firmware for some radios. But standardization will bring scale and ubiquity to non-technical users. Are millions of city occupants ready for transparent walls, floors and ceilings? Are businesses ready for remote keystroke detection?


I guess the future is RF blocking walls. Might even be a good thing since It'll allow for less congested airwaves for yourself.


Maybe something like this foil-backed gypsum board, https://www.goldbondbuilding.com/products/drywall-panels/foi...

RF/sound blocking drywall for SCIFs costs a small fortune, https://www.quietrock.com/products/quietrock-530rf

EMF shielding case study, https://www.zokazola.com/emf_reduction.html


You can get a lot of sound proofing by double layering drywall with an air gap in-between in exchange for some floor space.


My apartment ceiling has a ~60cm air gap with air conditioner ducting and stuff inside, not sure how responsible it is but I hear basically nothing from above me. Same for the side walls although I believe those are just super dense fire proof walls.


I suggest the opposite - it will enable many exciting smart home possibilities which in some could seriously reduce HVAC energy needs beyond what’s possible today.


You could leave the internal walls RF transparent. Which allows you to do whatever you want without your neighbors wifi scanning you.


Building energy efficient homes also does that. No need to over complicate the situation.


Lot easier to deploy WiFi in existing homes than build new one. It’s about easy impact on the world.


> remote keystroke detection

Wait what..? Is it that good? That's even more terrifying


2015 paper, https://dl.acm.org/doi/abs/10.1145/2789168.2790109

> We implemented the WiKey system using a TP-Link TL-WR1043ND WiFi router and a Lenovo X200 laptop. WiKey achieves more than 97.5% detection rate for detecting the keystroke and 96.4% recognition accuracy for classifying single keys. In real-world experiments, WiKey can recognize keystrokes in a continuously typed sentence with an accuracy of 93.5%.

More papers on keystroke recognition: https://scholar.google.com/scholar?hl=en&as_sdt=5%2C31&sciod...

60Ghz mmWave radar (coming to Wi-Fi via 802.11ay) has higher resolution, shorter range and low ability to penetrate building walls, but can pass through unshielded windows: https://news.ycombinator.com/item?id=30172647.


Thankfully I use an extreme custom keyboard layout so I wish them luck.


That's about as hard as decrypting substitution cipher. Just think about the problem for a second, you will figure out how to trivially go around it.


Well I think with enough time you could just use the key press model to try different configurations until you got one that gave intelligible results. The process could be easily automated if the resolution is enough to support accuracy in the 90th percentile


That’s just as secure as ROT13


Do you also have your number keys remapped non-linearly?


> there are companies such as Cognitive

It's my understanding that there have been companies trying to sell solutions like this for people-tracking indoors for supermarkets/grocery stores, shopping malls, large department stores for at least 7-8 years now.

(edit: Stuff like RF beacons built into shopping cart handles, right? Since the shopping carts are centrally owned/managed/controlled and with unique serial numbers, and mostly don't get stolen or leave the property.)


Your understanding is correct, but most of those were based on iBeacons/NFC/other tech and not Wi-Fi.


There were some things around WiFi, but on a higher level, e.g. recognizing unique radio mac addresses that were sending probes for their home SSIDs. Big reason most devices will now randomize their MAC address until actually authenticated with a network.


Sounds like phrases out of 1984.


Can you give us an example of the kind of phase you're talking about?


does it thouuuugh?

I understand that references to 1984 are meant to convey an aversion to the potential of government surveillance, unavoidable totalitarian control, and a society that exists far after this has already occurred

but there aren't any phrases in that 73 year old book like that, kind of overused and dilutive


Just because the bad guys already has some power doesn’t mean we should be making things even easier for them.


Maybe they meant it more as a comparison to Winston's living situation and how he had to stand in one corner to not be seen if I remember correctly. The very first thing I thought of when I read through this here was how I might be less safe from observation by the government with this. And I'm really no anti or even small government type yet it's the first thing that came to mind.


It takes one person (somewhere between invention and extinction) to flip that switch.

I'm fairly convinced drone technology is a bad idea for the very same reason.


A variation of this was used in "The Dark Knight", and you'll recall that Morgan Freeman quit (ok or maybe threatened to quit per the comment below, we know he was back in The Dark Knight Rises) over the ethical implications.


I've never seen the movie, but was curious about it regardless. This is what I found about it, maybe others are as clueless about it as me:

> Fox [Lucius Fox, played by Morgan Freeman] eventually learned that Bruce [Batman] had expanded on sonar technology and developed an advanced surveillance system that could listen in and track the movement of any of the thousands of cell phones in Gotham, but, to ensure that the system was not misused, Bruce designed it so that only Fox could control it. Since that essentially contradicted everything that Bruce believed in, Fox agreed to help but said that he would resign if the machine was not destroyed after The Joker was defeated and captured. After the Joker was apprehended, Fox entered a code (his own name) as instructed by Bruce, which activated a self-destruct function for the system, and Fox continued to work under Bruce.

From https://batman.fandom.com/wiki/Lucius_Fox_(Nolanverse)#The_D...

Seems he never actually quit, but was fine pushing his own ethical concerns aside for a little while, and continued working with Batman afterwards.


> his own ethical concerns aside for a little while

everyone does this. In fact, surveillance is not an "ethical" concern.

It is just a concern from the standpoint of potential misuse. And no one thinks they themselves are going to misuse the powers they have. Everyone else is concerned that their powers will be one day misused. And misuse means the powers being used against people who everyone else associates with. No one cares if the powers are misused against "bad" people like pedophiles or terrorists or the person who murdered someone's sister.


> In fact, surveillance is not an "ethical" concern.

> It is just a concern from the standpoint of potential misuse.

No, those are two separate concerns.

The trouble is, there are other things that concern people (in the movie, catching the Joker) and when you have two conflicting concerns you need to choose between them.


That movie is the definition of a Broken Aesop though: "what are the ethical implications" and then it proceeds to immediately use the technology to prevent a major mass terror attack.

In a world where Lucious's concerns were taken seriously, the Joker would've blown up both barges and probably not been caught.

So the lesson is....mass surveillance is okay sometimes when the threat is great enough?


I think of it the way I think of torture, in the stereotypical scenario where a nuclear bomb has been hidden somewhere in the city and you're 99.9% sure the suspect you've got locked in your basement knows where it is. Go ahead and torture him if you feel like that's the utilitarian optimum... but if you're wrong (and if you survive the blast) then you deserve the harshest punishment available under law.

The problem I have is when agencies like the CIA employ torture, accomplish nothing, save no one, and get away with it scot-free. That's monstrous. I'd apply the same reasoning to the use and misuse of mass surveillance.

(BTW, if you enjoy contemplating scenarios like this, check out the movie Big Bad Wolves. It's one of those obscure sleepers that will stick with you for a while.)


The problem with your example is it's the situation in which torture (in fact interrogation in general) isn't going to work no matter what you do: it's an example of what I like to call "the car keys fallacy".

Most people contemplating torture think in terms of "how long would I let bad things happen to me before I handed over my car keys?". Not literally, of course, but nothing in their life is that important. If someone points a gun at you, handing over your car keys just makes sense.

What they should be thinking is "how long would I let bad things to happen to me, if I told the people doing them where my children are so they can go kill them?"

The guy with information on where the nuclear bomb is knows how long he has to hold out to make the information useless. Otherwise, why didn't he give it up the moment you arrested him and said "yeah you'll be in jail forever?". Or when you threatened to have him executed if it goes off? If none of these things are actually compelling to him, then why would any level of torture be effective when he already is accepting his life being over anyway?

People think torture is prohibited because it's a bad thing to do, and that would be a good reason to prohibit it. But it's not just that's it's bad, it's that it's ineffective. And it is a dangerous lie that allows ideas like CIA torture programs to exist that it is: that torture actually works, and is just taboo. Because it advances the idea that the man with the will to torture will have an advantage over the one who doesn't - or that not doing it is some type of luxury. It's an argument in favor of it, despite that the fact that CIA program never found a god damn thing - and that should be an optimum torture scenario, because there's no fixed timelines, no ticking clocks, just a promise of eternal torture.


The guy with information on where the nuclear bomb is knows how long he has to hold out to make the information useless. Otherwise, why didn't he give it up the moment you arrested him and said "yeah you'll be in jail forever?". Or when you threatened to have him executed if it goes off? If none of these things are actually compelling to him, then why would any level of torture be effective when he already is accepting his life being over anyway?

Eh, everybody's a game-theory guru until the $5 wrench comes out. Under the scenario I'm positing, there's no other way to stop the bomb from going off. The 0.001% chance that the suspect will break under torture is still better than nothing.


"If you talk, the people interrogating you will find and kill your children"

You don't value the information that someone else is protecting as highly as they do, so you assume that some level of pain motivation is going to make them share it because it would make you share it. But almost anything will make an ordinary person share information they don't value, because they don't value it.

Torture is literally worse then nothing, because you've wiped away the ability to engage in meaningful interrogation in the time you have. It is inherently adversarial, and humans are really good at fighting back against perceived aggression: this is such a problem that interrogation specialists spend a lot of time educating police and military on what not to do. "Good cop, bad cop" is actually exactly the wrong thing to do because the "bad cop" undoes the entire repore you've built with the subject because they throw their mental defenses back up.

The CIA really wants it to work, to the point that they lied to the producers of Zero Dark Thirty about how they got the intelligence that led to finding Osama Bin Laden...but that's not how they got it. They absolutely tortured that guy, but he had already disclosed the intelligence they needed before they did any of it.[1]

[1] https://time.com/3627694/torture-report-zero-dark-thirty/


Torture is literally worse then nothing, because you've wiped away the ability to engage in meaningful interrogation in the time you have

Then I'll add a further complication to the scenario: all of those avenues have been exhausted. E.g., the torturer is a low-level cop, hired for his loyalty, bravery, and modest IQ. He is not a "good cop" at all, so the only tool he has is the proverbial $5 wrench. An interesting question is, having used the tool, what should happen to the cop if it succeeds?

They absolutely tortured that guy, but he had already disclosed the intelligence they needed before they did any of it.

I think I was pretty clear that I was condemning that. Right there with you. But I don't agree that there are no conceivable circumstances in which torture or mass surveillance is appropriate. They just don't arise very often. I wouldn't be surprised if they never have, outside of a Batman movie or Tom Clancy novel.

As for torture always being ineffective, terrorists often fail to live up to their stated ideals. Someone who plants a bomb may see it as a painless, instantaneous ticket to Paradise, but the chair he's tied to doesn't look much like a holy stargate or whatever, and the upset cop standing there with a wrench doesn't look like a virgin. It's unrealistic to assume that the cop's chance of success is 0%.


> It's unrealistic to assume that the cop's chance of success is 0%.

It's realistic to assume that they'd have better odds of getting what they want by putting down the wrench and trying something other than torture :

https://www.psychologytoday.com/us/blog/slightly-blighty/201...

https://nationalinterest.org/feature/the-ticking-bomb-dilemm...


Again: this particular cop doesn't read Psychology Today.


> The 0.001% chance that the suspect will break under torture is still better than nothing.

And also a chance a suspect will lie to you and send you on a wild goose chase.


That falls into the 99.999% of cases. It's a simple binary outcome: torture will work in a particular case or it won't. It almost certainly won't work for this or any number of other reasons, but in the scenario described, it's all you've got.

If you choose to torture the suspect, you're the bad guy, and the only way you can come back from a crime of that nature is by successfully saving the city. Any other outcome should bring a lifetime of punishment as a warning to the next person who thinks torture is a good idea "just this once."

Anyway, this has gone off the rails. Mass surveillance, like torture, is so abhorrent that it is justifiable only in cases where someone has reached deep into a barrel of worn-out Hollywood clichés. When those vanishingly-rare cases arise in real life, they will always have to be judged individually based on outcome. The law should not admit either tactic, not even in the defense of entire populations.


> I think of it the way I think of torture, in the stereotypical scenario where a nuclear bomb has been hidden somewhere in the city and you're 99.9% sure the suspect you've got locked in your basement knows where it is. Go ahead and torture him if you feel like that's the utilitarian optimum

Utilitarianism (of which there are many variations) is not the only moral philosophy that could support torture in such a situation.

Here is a thought experiment. You have strong evidence for the following: 1. A bomb has been planted; 2. Ten people know the location; 3. The bomb is only large enough to kill one or two people. (Perhaps it is hidden under one chair in a school.) Next, you detain the ten people. What do you do? Under what moral reasoning is coercion the least-worst option?

Torture (which I'll define as inflicting severe pain in the hopes of acquiring useful information) is one kind of coercion. (Unfortunately, torture is not necessarily the worst form.)

There are many moral philosophies that would hold the following: people who have knowledge of upcoming violence but do not offer it freely forfeit some of their usual rights with respect to coercion.

Personally, I have not found much detailed discussion of how uncertainty weighs in to these ethical considerations. What I have seen is rather hand-wavy.


> In a world where Lucious's concerns were taken seriously, the Joker would've blown up both barges and probably not been caught.

Ummm... why?

Of course sometimes that technology can actually be used to achieve good ends. Otherwise we would never be tempted to use it.

What makes it an ethical problem is that, despite being useful, some people prefer not to use it for ethical reasons.


The entire movie, in my estimation, is understanding the feelings of paranoia post-9/11. The point was that while ideally, we would like to be like Lucious and have principles, the fear of terrorism justified mass-surveillance. (Honestly, it’s amazing the movie was released pre-Snowden)


How "mass" are we talking? UK's CCTV seems reasonable. Just on the streets. Don't need people watching what I'm doing in my own home.


“It’s sonar… Like a,”

“Like a submarine, Mr. Wayne.”


*Knight


Haha right I don't know if that was autocorrect or just me zoning out. Probably the ladder


*Latter


The paper trains a model that a. requires training data in a specific environment. Meaning, to deploy this tech, you need access to the space first to train this model. b. once trained, will not transfer its knowledge if routers are moved, or setup is deployed in a new area. c. training was done with just a single person moving. multiple people moving was not evaluated by this tech/probably harder to achieve. With that in mind, I think privacy-invasion capability of this technology is exaggerated by some comments here.


This specific paper is only one of several hundred papers from a decade of research leading to IEEE standardization, https://dhalperi.github.io/linux-80211n-csitool/#external

From a 2021 paper on IEEE 802.11bf Wi-Fi Sensing, https://arxiv.org/pdf/2103.14918.pdf

> Indeed, it has been shown that SENS-based classifiers can infer privacy-critical information such as keyboard typing, gesture recognition and activity tracking ... since Wi- Fi signals can penetrate hard objects and can be used without the presence of light, end-users may not even realize they are being tracked .. individuals should be provided the opportunity to opt out of SENS services – to avoid being monitored and tracked by the Wi-Fi devices around them. This would require the widespread introduction of reliable SENS algorithm for human or animal identification.

200 comments on privacy vs. utility, Jan 2022, https://news.ycombinator.com/item?id=29901587


There are scenarios where you can record data first, and then train with later access to the space. Then process recorded data.


> Meaning, to deploy this tech, you need access to the space first to train this model.

Government secret services have gone and re-built the houses of high-profile raid targets before. And it's only a matter of time until simulation technology becomes powerful enough to do a "good enough" digital recreation from blueprints.

> multiple people moving was not evaluated by this tech/probably harder to achieve

At least one scenario in the article mentions "a room with several people". People moving around is just a question of speeding up data collection and analysis.

> With that in mind, I think privacy-invasion capability of this technology is exaggerated by some comments here.

The key thing is, what is public research grade now, is likely already a developed asset in government toolkits. And now that the general public has access to such technology, it will - more likely than not, given it can be done on 50$ low-cost devices - be commoditized, particularly where there is a financial interest in tracking people. I think a good candidate will be supermarkets and similar stores - at least in Europe, stuff like running analytics on surveillance cameras is pretty frowned upon under GDPR, but something like wifi-based tracking should be relatively unproblematic.


Stores already commonly track people's movements and repeat visits by their cell phones. Bluetooth beacons are used to log any device that wanders near enough. No need for wifi tracking.


Perfect for hotel rooms then


Pretty cool. Semi-related but reminds me of this research from MIT on seeing around corners:

https://youtu.be/JWDocXPy-iQ


We have radar capable satellites we use to bounce a signal off the ground, through a hanger door and then reconstruct the image to discern what is hidden there.

https://www.youtube.com/watch?v=ztR9mdJ1YWU

https://www.youtube.com/watch?v=u2bUKEi9It4

https://www.youtube.com/watch?v=dOoCltqtJR8


Yes! And seeing through a keyhole! https://youtu.be/Veo27qhrI20


Wow that video was short, informative, and very cool in a retro sort of way. Thanks.


They can also do this without the laser by detecting shadows from existing light sources that aren't visible to the naked eye.


I spend so much time thinking about this as an entrepreneur and whenever I talk use cases people seem to not care.


I read "used to" in the title in the past tense form. For a moment I was wondering why they no longer produce 3D images.



I came here to bring the exact same joke. Rest in peace, Mitch.


The code was lost eons ago, sadly :'(


Me too. I'd expect "Using WiFi Routers to Produce 3D Images of Humans" if it were present tense.


Did Lucius Fox resign or re-sign?


Is there a better source than a random VPN comparison website that exists to promote affiliate links?



Thank you very much. The PDF link in this article wasn't even working; your link works. Thanks!


> In addition, they protect individuals’ privacy and the required equipment can be bought at a reasonable price.

To argue that this protects people's privacy (versus cameras in public spaces) is certainly a very odd take.

I'd be more curious to know what are legitimate use cases of this and who funded the research.


It's kind of like the way they renamed the Department of War to the Department of Defense.


We have done the same and published back in early 2020. THis paper does reference our work as [11]. Blog post with our human detection video here (eerie !):

https://futurebnd.com/human-detection-classification-and-vis...

and the paper here:

https://arxiv.org/pdf/2001.05842.pdf


I would really like to see a practical open source implementation of this so people can start looking for ways to defeat it. Otherwise you know the police are going to abuse this.


Things like this have been known for a while, and for some reason now being talked about in mainstream.

Talking about / showing things as an early "adopter" (ECHELON, Snowden stuff pre-Snowden, etc.) tends to get people angry and you slandered with vitriolic things like "conspiracy theorist" so the juice is not worth the squeeze.


the life of a politically inconvenient story:

1. it's conspiracy theory

2. it was obvious to everyone

3. forgotten


Short of lining your walls with foil, how could you defeat it legally? Jamming isn't legal.

We need new legislation to ban this, without a law enforcement exemption. I don't have high hopes.


"Jamming" is legal in as much as any device that operates in the ISM[0] bands must accept interference - so in the 2.4GHz example, microwave ovens, baby monitors, TV relays, remote door monitors, wireless alarm systems etc., all operate in the same band and will interfere with WiFi that is close by (since they use a different modulation).

[0] https://en.wikipedia.org/wiki/ISM_radio_band


You are correct that ISM band devices must accept interference, however jamming is illegal in the USA due to FCC regulations: https://www.fcc.gov/general/jammer-enforcement

Definitely start with the presumption it is illegal anywhere in the world, even though you might be able to hack around regulations to find loopholes. I think the FCC is focused on broadcast interference, safety requirements, and commercial sales of jamming devices.


And in college I remember a professor or a TA demonstrated jamming by operating a modified microwave oven while running iperf or something similar on a nearby Wi-Fi network.


I would take a wild guess that it wouldn't be jamming, but some sort of network configuration. Maybe something like extra access points with specific geometry, higher power exterior APs than interior APs, or random beam forming or reflections.

Jamming could still be an option. Most devices are required to accept any interference from other lawful devices. So in theory, you could find legal ways of jamming.

https://www.zdnet.com/article/how-to-jam-your-neighbors-wi-f...


The same law that says you must accept interference also says you may not cause interference, or something like that.

You could only legally jam by making transmissions that are actually useful and just happen to also interfere.

IANAL.


Lining the exterior walls doesn't sound all that hard for a new build. Just lay the RF blocking sheet down before the drywall. People love those RF blocking wallets that have dubious value, a "privacy wall" upgrade from builders would probably sell well.


They can sell it as improving Wi-Fi in your own home too, even if you trust neighbors not to pull any shenanigans, since your Wi-Fi network won't be subject to interference from neighboring networks.


Downside is that your cellphones would also stop working indoors.


That's an inconvenience for guests but you could stick a QR code to join your wifi on the wall. Phone calls should still work over wifi calling I'd think.


Just put a mini cell tower/booster on the inside of your house connected via wire to the outside. Problem solved, and you now have the ability to cut off cell access on the inside if you want to.


Okay so nobody will buy it.


It’s not some “radio gun” you can just point at a house - you need a very calibrated setup purpose built for each space. This would be very obvious and would require access to inside to do the calibrations.

There are far more obvious ways to know if someone is home, from thermal sensors, looking in windows and knocking on doors, or park outside and just watch.

Further if the police want to know if you’re home, it’d already game over.


Yes and 5 years ago the most impressive thing “AI” could do is tell you if an object was a cat or a banana. Now it can hold complex conversations and write computer code.

It’s never too early to start thinking of the implications of technology. It’s not inconceivable that in a few years every crooked small town cop will have access to tools straight out of science fiction- tools that started out as innocuous research.


DHS 2014 report on ~$10K handheld devices for through-wall-surveillance, https://www.dhs.gov/sites/default/files/publications/Radar-T...

X-Ray vans (2015), https://www.foxnews.com/science/x-ray-vans-security-measure-...

> The Z Backscatter Van (ZBV), manufactured by American Science and Engineering .. can also see through clothing and into some buildings, are raising privacy concerns as well as questions about health risks ... the van -- which looks like a standard delivery van -- takes less than 15 seconds to scan a vehicle; it can be operated remotely from more than 1,500 feet ... vans range in cost from $729,000 to $825,000.


> There are far more obvious ways to know if someone is home, from thermal sensors, looking in windows and knocking on doors, or park outside and just watch.

All of these have the disadvantage that the observer can be spotted - there exist numerous articles on how to spot cameras because sketchy AirBnB hosts placed hidden cameras in bedrooms and toilets. A radio-based monitor however doesn't need line of sight - if small enough, it can be hidden just about anywhere where no one looks, like the interior of a rainwater tank, under the bottom of a trash can, in a roof water drain.


You can record first, and calibrate/train later. Then analyze recorded data.


"WiFi Routers Estimates 3D Pose of Humans in Modelled Reconstruction" as an actual non bullshit title. The paper being a more concise "DensePose from WiFi".


Can we use this sort of processing power and analysis to figure out how to get better signal coverage in a property instead?


Are you interested in joining our human mesh network? For the price of 420.69 we offer a wearable necklace with a raspberry pi attached to it and a green solar panel t-shirt to ensure power/uptime. Become the internet now! Restriction may apply, sorry not available in Hawaii or Alaska.


The photo in article is some random stock image and has nothing to do with the research paper[1].

[1] https://vpnoverview.com/wp-content/uploads/2301.00250.pdf


Oh wow. Notably, Figures 7 and 8 (on pages 7 and 10, respectively) are better resolved than the stock photo.

Figure 8 shows a variety of "failure cases," but even these failure cases are surprisingly accurate estimations!


If I understand the captions correctly, the wireframe images overlaid on RGB images are from the algorithm run on the RGB images, not the wifi data, so having them match up is not surprising.

The standalone wireframe images sometimes manage to get the number of people and their approximate positions correct, but everything else about them seems (IMO) believable but not necessarily accurate, like most AI output.

This doesn't surprise me, because the input data is very coarse. Look at their graphs. There's just not enough raw data there to accurately reconstruct much other than position in the room.

I'm sure it's possible to do more accurate recording and reconstruction, I just don't think this demonstrates it.


Is that link broken for anyone else? Redirects back to the top level page for me


Try https://arxiv.org/pdf/2301.00250.pdf -- looks like they removed the original PDF from the linked article.


It wouldn't surprise me if the three letter agencies were already utilising this.


I doubt it. If they want to see you though a wall, they will use an overpriced custom radar solution, not consumer electronics with COTS software.


But the consumer electronics are already in position.


Both have an application. This can be employed at bulk.

Say for example they still wanted to find bin laden, they can do a mass look for people 6ft 4 type search which would narrow things down significantly. Then have a more detailed look with custom radar or other of worth while.

Maybe a poor off the cuff example but that kinda of bulk information collection.


"Meat interferes with photons" must be among the least-surprising research outcomes of all time.


yet, people still discard the idea that EMFs can have health effects ??


Slightly related,a little dated, but relevant reminder:

Rebehold, the Range-R: https://en.m.wikipedia.org/wiki/Range-R

https://www.usatoday.com/story/news/2015/01/19/police-radar-...


Pretty similar to an older Nature paper, using smart speakers to monitor heart rate.

Wang, A., Nguyen, D., Sridhar, A.R. et al. Using smart speakers to contactlessly monitor heart rhythms. Commun Biol 4, 319 (2021). https://doi.org/10.1038/s42003-021-01824-9


Is this the paper where they try and detect "emotional states" from heart rate and motion with moderate success? I could imagine this technology being deployed in public spaces in autocratic/repressive countries to screen for citizens who seem to be feeling hostile or angry.


Is there something low-cost and purpose-built to do this at short range, for when you just want to do some body tracking for VR/metaverse stuff? The trouble with doing this with a webcam is that occlusion results in errors and the avatar's limbs jump around. This sort of RF thing has more field of view, too.


This MS/Stanford project looks relevant, https://web.stanford.edu/~mkotaru/wicapture & https://www.science.org/content/article/wi-fi-could-protect-...

Commercially, Plume has 200K early adopters of Wi-Fi Sensing for human presence, but not VR specific, https://www.protocol.com/plume-wifi-data-intelligence

> Plume began testing Wi-Fi motion detection technology developed by Cognitive Systems in early 2020, and the company is now considering offering additional services atop of that technology. These could include triggers that help consumers save energy by automatically turning off lights after someone leaves a room, or even provide security and elder care products.

Amazon Echo uses ultrasound for motion detection.


> This MS/Stanford project looks relevant,

That's not imaging, that's tracking a WiFi equipped target. That's pretty standard now. Sony's Mocopi is probably the most elegant implementation.[1] Tundra Tracker [2] also gets good reviews.

Motion detection is much lower rez. Ultrasound is like trying to sense the world with a probe the size of a broom.

[1] https://www.youtube.com/watch?v=ovHHpralCD8&t=3s

[2] https://www.youtube.com/watch?v=ImEKHrUp4QM


This one tracks limbs, https://dl.acm.org/doi/abs/10.1145/3447993.3482857 & https://techxplore.com/news/2021-11-winect-tracks-3d-human-p...

> Our system tracks free-form activity by estimating a 3D skeleton pose that consists of a set of joints of the human body. In particular, Winect first identifies the moving limbs by leveraging the signals reflected off the human body and separates the entangled signals for each limb. Then, our system tracks each limb and constructs a 3D skeleton of the body by modeling the inherent relationship between the movements of the limb and the corresponding joints. Our evaluation results show that Winect achieves centimeter-level accuracy for free-form activity tracking under various environments.

~200 papers for VR + CSI, ~30 for 2022, https://scholar.google.com/scholar?hl=en&as_sdt=40005&sciodt...


For future, please share any thing you find.

I have some "quantified self" use cases that I'd like to try out.

- Monitor my breathing, nudge me when I'm holding my breath.

- Monitor my posture, nudge me as needed.

- Real time feedback for learning tai chi, qi gong, etc.


I used to get excited about the benefical uses of new tech. Now, I'm expecting to be charged 19.95 subscription (for data that should never and doesn't really need to leave the LAN) for the privliege of amazon tracking my movements so they know when to send TP JIT. Thank you guys


It's not new as you could think after reading the article. I remember reading about this technology - seeing humans through walls basing on internal wifi signal for some US government agencies - at least 7y ago. Also OpenWRT software for routers has plugin for gestures for MANY years already. Possibilities of reading gestures by your home router implies all mentioned use cases.

It's past, but written here as a future. It's truism but written as discovery.

Another truism would be saying that it scales for any radio antennas - like GSM. Especially if you have dense grid.


I really wish we would make more of WiFi routers, AVM with their Fritzboxes seem to be the only ones doing something interesting, with features like SIP Server, SAT>IP Server, Internet Radio etc.

Routers can have attached storage, why can't we backup our phones to them instead of iCloud (instead of workarounds like Nextcloud)? Why can't they directly provide location information over a standard protocol, thus potentially avoiding a request to a cloud service?


Can see it already. Sounds like a breakthrough in urban warfare. Swarm of drones flying around mapping enemy positions live like a video game. Scary


i'd like to understand wtf my upstairs neighbor is doing. can this help me?


Is she hot? If so, then maybe when she complains to the police about you (or whoever) a sudden negative land slide against this sort of technology will ensure.


Yay for connected fridge reselling your data /s


There's a reason the Five Eyes issued such firm caution about 5G hardware and the reason is that 5G is sensing infrastructure.


I remember seeing a similar study years back… the claim was tracking of positions of bodies. The mechanism reminded me of Project Soli, using signal processing to make 2D/3D inferences. This sounds like the next iteration on that finding. Wild.



Seems like they've remove the PDF from the article.

You can get the original PDF from Arxiv : https://arxiv.org/abs/2301.00250


> This proof-of-concept would be a breakthrough for healthcare, security, gaming (VR), and a host of other industries.

They forgot the panopticon and Big Brother. Big breakthrough here as well!

Enjoy the week people, funky times ahead :)


Can't wait for the day when those scientists start coming up with systems that intelligently assess whether your wifi, phone, or even just electricity wires are being hijacked by malicious actors.


MIT CSAIL had an extremely similar project way back in 2015:

http://rfcapture.csail.mit.edu/


The more unexpected discoveries we find, the more I think how many more capabilities of everyday devices are "hiding" in plainsight that would surprise us.


DDGing "Faraday wallpaper"...


This sounds like something the military should already have figured out.


Is anyone aware of any open source tools for this kind of thing?


Two github repos linked in this comment, https://news.ycombinator.com/item?id=34482094


Wifi was already submitted as an imaging specification...


I would love to use this for full body tracking in VR


I have to remember not to walk naked around my Wi-Fi


Urban special ops already use some version of this.


You may be working with people who, at the beginning of their careers, worked on exciting and challenging projects as junior engineers for U.S. defense contractors to either detect the precise location of specific Wi-Fi clients.

Ask them when they realized that their work was extensible to any radio frequency client (cell, Bluetooth) and used for targetting missile strikes. I can guarantee you know at least a few people in the industry who did.

Just because we can doesn't mean we should. This story reeks of DoD funded research which somehow gets whitewashed as "cool new tech thing!" on tech blogs when it should really be sending chills down your collective spines.

This capability may be fringe and nation-state controlled for a few years, then it will inevitably fall into the hands of large and well-funded criminal organizations, abusive spouses, and of course overfunded trigger happy SWAT teams — who will still manage to get their court order addresses wrong and kill innocent people and pets over a no-knock warrant.

All this triggers in me is the irrespressible urge to get technologists to finally get it through their thick skulls that what we do does kill people exactly like doctors. We've just refuse to take responsibility for it when any other industry would have seriously discussed ethics board and licensure at this point. No matter how complicated such an effort would be.


I’ve noticed a distinct lack of caring regarding social responsibility in the tech industry even though we are some of the most privileged workers in the entire labor force.


>I’ve noticed a distinct lack of caring regarding social responsibility in the tech industry even though we are some of the most privileged workers in the entire labor force.

I'd posit that "lack of caring" in the tech industry is, at least in part, because (not "even though") "we are some of the most privileged workers in the entire labor force."

It's hubris, greed and a lack of empathy for society at large and for other humans.

There definitely are folks who do care. But when such folks speak out, they are usually ignored or derided for "tilting at windmills" because "privacy no longer exists" and "there's money to be made" and other weak-sauce rationalizations.

And the hoi polloi mostly don't understand the issues, and just like having "free" services, not realizing they're still paying. With their data, privacy and online (and increasingly offline, with cameras everywhere, spying "IOT" devices, brisk business for data brokers, etc.) personages in the hands of (at least based on their behavior) sociopathic tech bros whose only interest is in maximizing revenue -- and today that's accomplished through "targeted advertising."

Which doesn't really work, but advertisers are willing to pay top dollar for such data in the amoral pursuit of greater profit. Not that profit is, in and of itself, bad. But abusing others to get that profit is bad.

Others, political operatives, some law "enforcement" agencies, stalkers and other scum that it does "work" for are focused on advancing their agendas, avoiding real police work and harming others, not making the world a better place.

Until the incentives are the right way round, that's not going to change.

I'd love to paint a picture of benevolent tech workers/managers/founders who have society's and the individual's best interests at heart.

But (with apologies to Quentin Tarantino), that shit ain't the truth. The truth is the hoi polloi are the weak. And we're the tyranny of evil men. cf. The banality of evil[0].

[0][ https://www.britannica.com/story/what-did-hannah-arendt-real...

Edit: Fixed prose. Added Hannah Arendt quote and discussion of same.


> their work was extensible to any radio frequency client (cell, Bluetooth) and used for targetting missile strikes

Good. I didn't work on such tech, but I would be excited and proud to, if I was working for a country like US, which I believe in.


Proud of the tens of thousands of Iraqi civilians killed by the US?


I think you lowballed that by a factor of 10


This proof-of-concept would be a breakthrough for healthcare, security, gaming (VR), and a host of other industries.

/facepalm

They do acknowledge the privacy concerns but go to make (imho) pie-in-the-sky arguments like 'this will enhance privacy because security cameras won't be as necessary in public spaces. Journalism doesn't pay much, so maybe this is some naively idealistic person's first writing job. I once believed that adding public comments on news websites would elevate the standard of public discourse and I mentally kick myself on the regular for the time I spent promoting this idea back in the 1990s.

The researchers offering the same ideas in the paper don't have such an excuse; they're creating an entire new class of surveillance technology and pretending that this will somehow enhance privacy, which flies in the face of all experience and research on the topic. The technicals result are outstanding and I'm very impressed by them, as well as the exposition and direction of research. The potential applications are numerous and exciting to my inner geek.

But I'm also worried. The existing limitations will fall sooner than expected, and it will be productized while the ethicists are still drafting their arguments (at which point they'll shift to asking for donations to counter the latest threat). Semi-seriously considering repainting the inside of my house to make a faraday cage by mixing copper paint in the underlayer.


The thing is, almost all technology is a double edged sword. That doesn’t do much to alleviate the responsibility of those who do it to understand the ethics of the world, but usually that’s beyond our ability. I’m sure few working on consumer drones in the beginning anticipated their use on the battle field.

The internet itself is a great example of how much benefit can come from access to knowledge, as well as the ability to how limitless (mis)knowledge can be simultaneously used to destroy societies.

Ultimately bad actors will do bad things regardless with whatever they have access to. Of course new bad things can come along, but what metric should we use to decide whether an idea is worth perusing? Who should make the cost benefit analysis, when the reality 20 years down the road is often unknowable (bad and good)?


I guess we'll just keep rolling the dice until someone stumbles on a planet-killer technology. Sound far fetched? So did disinfectants to people 200 years ago. And nuclear weapons to people 100 years ago.

I admit I am bit fatalistic about all this, but perhaps that explains why we haven't encountered aliens yet. Too many landmines in the tech roadmap and they inevitably blow themselves up :-)


> Semi-seriously considering repainting the inside of my house to make a faraday cage by mixing copper paint in the underlayer.

EMF reduction case study with conductive paint, https://www.zokazola.com/emf_reduction.html


>>Semi-seriously considering repainting

So they have Blackboard paint, how long before PPG or Sherwin Williams creates Faraday Paint...


Some examples of RF shielding (conductive) paint, https://emfacademy.com/emf-paint/


Could you do a thing where you have a little nook in which to place your cellphone so you can still receive calls?


This is why I put tape over my Wi-Fi router


I guess wearing a tin foil hat might be useful too


Really putting the router in an aluminum enclosure/Faraday cage if you can is the only way to prevent this. Then just use the lan ports on the device, but also make sure the LAN cables are shielded because it could be using them as antennas given how compromised wifi router firmwares usually are.


In the past I've opened up my provider-supplied cable modem and removed the wifi card which was luckily modular.

This was a really retarded ISP (UPC Ireland) that constantly (like bi-weekly) reset my modem to its factory settings including a way-too-simple wifi password of 8 uppercase characters excluding the I, L and O for number confusion reasons. The entropy was so low that I could crack so my neighbor's passwords in half a day. Basically they were backdooring my entire network.

I emailed them but of course nothing happened. Eventually someone even reversed the algorithm they used (based on the SSID of course....) and published a generator which they reacted to by only sightly tweaking the algorithm which of course got reversed again. They also disabled other features that could alleviate this like bridge mode. It was such a terrible company with extreme contempt for their customers but sadly the only fast one I could get in that backwater town.

But anyway removing the wifi module fixed that huge backdoor at least. I kept all the parts to put it back, but when I quit the service the modem was deprecated and they told me to throw it out.

Later they got taken over by virgin media, not sure if they're still as bad because I left the country.


You have to shield your home from your neighbor's emitters too. And from the police radar surveillance van sitting in the street in front of your house.


>... And from the police radar surveillance van sitting in the street in front of your house.

Nothing a kind note and an order of small-batch artisan donuts can't solve.


> You have to shield your home from your neighbor's emitters too. And from the police radar surveillance van sitting in the street in front of your house.

That's what tin foil houses are for, obviously.


And for saving them from raging wildfires. (Seriously! Wrapping a structure completely in foil can save it, even when that structure is in a forest with no clearing arund it. I guess it's like baking a potato in hot coals.)


What do I do about my thermal signature though?


Cover yourself in mud from a river bank.


Wim Hoff method. ;)


And space lasers.


>Then just use the lan ports on the device, but also make sure the LAN cables are shielded because it could be using them as antennas given how compromised wifi router firmwares usually are.

Those shielded Ethernet cables better be properly grounded.


Come on that’s just plain silly, they’ll just see you dancing around naked in your hat. It’s not like Wi-Fi routers can see inside your brain, as the article clearly says. No one on HN ever reads the article before commenting any more!

The hat only works against the microwave oven mind control. Sheesh.


No, that's the magnetite paint for the microwave that does that. Tin foil is for the Nostradamus brain rays from Uranus.


I prefer to wear a tin foil suit thank you.


I know this is a joke, but wouldn't that still leave a you sized hole?


You can also get creative with a metallic fishnet fabric.


> * * *

Why do you post this? It doesn't add to anything.


only electrical tape will work though. it's the only one that actually blocks electrons


Except we’re talking about photons…


photons, electrons, always ons, ahh what's the difference


I don't get it, how will tape help?


It's a joke about covering webcameras with tape to block it.


Yet another reason to avoid Xfinity hardware.




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