This is a VERY controlled environment - and they used 20 passes of each person walking with direct knowledge of each person to train for identity. They did no tests with multiple people walking at the same time, or with any other external moving distortion effects (doors opening, etc) . This is very far from actual 'identification' of people in real public settings - and no doubt the cell phone everyone is carrying with them offers many orders of magnitude better opportunity. In a real crowded environment this would be nearly worthless.
The devices that reported BFI information were also stationary, and there were no extra devices transmitting information that would be conflicting.
A single camera would be much more effective.
show comments
alexpotato
Not sure how many people are aware that the newer Alexa devices have "presence detection" that uses ultrasound so they can detect when people are nearby. [0]
Heck, even Ecobee remote temperature sensors can do this.
Reminds me of the story about how the Google Nest smoke detector had a microphone in it. [1]
> The method takes advantage of normal network communication between connected devices and the router. These devices regularly send feedback signals within the network, known as beamforming feedback information (BFI), which are transmitted without encryption and can be read by anyone within range.
> By collecting this data, images of people can be generated from multiple perspectives, allowing individuals to be identified. Once the machine learning model has been trained, the identification process takes only a few seconds.
> In a study with 197 participants, the team could infer the identity of persons with almost 100% accuracy – independently of the perspective or their gait.
So what's the resolution of these images, and what's visible/invisible to them? Does it pick up your clothes? Your flesh? Or mosty your bones?
show comments
darepublic
Correct me if I'm wrong but assuming they didn't already know your identity, wearing a mask for instance would prevent profiling you based on your radio wave constructed facial features.
barrystaes
Android devices already know exactly where they are even with GPS disabled, because they sniff the nearby WIFI networks and then ask Google where they are. QED Google knows already, all combined is mass metadata surveillance already provided to those that tap into it.
Any sub-meter precision or presence detection does not really matter, if these companies have all your other questions, queries, messages, calendars, browse history, app usage, and streaming behaviour as well.
show comments
palata
This "could become" sounds exactly like when you look at a cool robotics project, and when you ask the researcher what it could be used for, they say "it could be used for search & rescue after a natural disaster".
The truth is that it's cool research that currently has zero use-case. But a) journalists would not write about that and b) researchers may try to use examples to explain what their research does. Probably researchers are tempted to find a cool use-case of course, because it's better for them if journalists write about their research.
This sounds like cool research that is not remotely close to becoming an invisible mass surveillance system.
srcreigh
Various cheating to get their conclusions (from the paper):
> To allow for an unobstructed gait recording, participants were instructed not to wear any baggy clothes, skirts, dresses or heeled shoes.
> Due to technical unreliabiltities, not all recordings resulted in usable data. For our experiments, we use 170 and 161 participants for CSI and BFI, respectively. [out of 197]
I wish they had explained what the technical unreliabilities were.
bagels
WiFi is already part of invisible mass surveillance systems, though not in the way described in the article. It's part of how cell phones fix location, based on nearby wifi endpoints, which is then sent to google, apple, every app, every advertiser, etc.
Legend2440
I'm skeptical; this seems like a pretty crappy way to do surveillance. Cameras give you much more information.
I remember reading about this in a Cory Doctorow novel decades ago, Eastern Standard Tribe, I think.
chasd00
Funny how mass surveillance concerns are popping up here and there these days. That boat sailed 20 years ago.
Bender
WiFi Could Become an Invisible Mass Surveillance System
Highly unlikely and would be a waste of effort and resources. In the real world we are already well surveilled by cameras, microphones, satellites, cell phones, televisions, modern vehicles with a large number of cameras, web enabled doorbell cameras, refrigerators, AirTags, robot vacuum cleaners that map our home and monitor us, anything bluetooth enabled and that is even before actual spy devices like laser microphones that can turn most windows into a giant microphone.
All of these methods are far more attainable without trying to recreate microwave imaging that has been used by the feds for ages and the feds use a handheld device vs. this complex lab setup and this is even before we talk about advanced high resolution milspec FLIR which some companies have managed to get into serious trouble for selling to sanctioned countries for ITAR violations.
rubatuga
I was really impressed that a ESP32 Antenna Array Can essentially make a WiFi camera - it uses both time and phase differences to localize based on MAC addresses (which are sent plaintext) https://www.youtube.com/watch?v=sXwDrcd1t-E
show comments
puppycodes
There are much better invisible mass surveillance devices like the one you carry around in your pocket every day.
show comments
diggyhole
You're carrying a mass surveillance system in your pants pocket
blacksmith_tb
You can do it to yourself[1], I am using Tommy for presence detection in Home Assistant, works great (my house is small, so two ESP32s works fine, I am sure having 3-4 would let it see my cat breathing).
WiFi Sensing is part of Wi-Fi 7 and present in most recent laptops and smartphones. Local NPU machine learning can be combined with WiFI radar. Malware can attack phone and radio basebands and exploit this capability. It can uniquely fingerprint human biometrics, measure breathing rate, record keystrokes and more. Thousands of academic papers have been published in the last 15 years on "device free wireless sensing", before the capability was ratified by IEEE as 802.11bf. It's being rolled out commercially. Mitigations include drywall or insulation with a layer of RF shielding.
> Researchers.. developed.. a biometric identifier for people based on the way the human body interferes with Wi-Fi signal propagation.. CSI in the context of Wi-Fi devices refers to information about the amplitude and phase of electromagnetic transmissions.. interact with the human body in a way that results in person-specific distortions.. processed by a deep neural network, the result is a unique data signature.. [for] signal-based Re-ID systems
glitchc
Caveat: Indoors. However, since indoors is typically a private space, the degree of surveillance depends on the owner of the space. Civilians can only compel government agencies to make sure that government buildings do not enable tracking. We won't be able to stop Walmart, they can always play the security card which trumps privacy every time.
show comments
thedangler
How good is ethernet over electrical sockets these days.
I had one about 15 years ago maybe, but it wasn't that good.
Has tech changed. I'd use it over my wifi setup if its was fast.
show comments
boring-human
Could this be countered by wearing wire-mesh patch clothing, perhaps in randomized stylish arrangements?
show comments
dpc050505
Cameras just use light waves and are already a mass surveillance system.
> In a study with 197 participants, the team could infer the identity of persons with almost 100% accuracy
That a super impressive! I wonder how that would be at scale, with a few millions people. I’m don’t think that would remain as accurate
j3th9n
Who cares, we have nothing to hide.
gnarlouse
So, should I start walking around with a jammer or something?
show comments
TimTheTinker
I don't see how this is categorically any different from hidden networked cameras. Perhaps that's the real issue we should be focusing on in terms of privacy and mass surveillance.
misiek08
Scary title, 3 month late into the party… really we don’t deserve better articles with non-dramatic content, much faster?
ddtaylor
Xfinity does it or at least say they do.
an-allen
Could? Is mate. Is.
cauenapier
Perhaps we should ask be using aluminium foil hat now
toss1
"As radio waves move through a space and interact with people, they create distinctive patterns that can be captured and analyzed. These patterns are comparable to images produced by cameras, but they are formed using radio signals rather than light. "
The concept sounds not unlike like the multispectral imaging produced by Geordi's visor in TNG.
Seems conceptually possible, but likely too much computing power and observing time (to build up and learn each individual's pattern in that part of the RF band), at least in current times.
I'm sure it could be developed to work in the field, but what is the use case where it pays off to make the silly-money investment to make it happen? Especially so when it's far easier to simply notice pings and get better data when approximately everyone always carries their mobile phone.
bitbytebane
LOL @ "Could"
Nothing says "out of touch with reality" like 'murcan media.
kittikitti
Beamforming information is utilized for creating this surveillance. There are also a lack of configurations in common routers to turn off BFI. The BFI information is available to any WiFi snooping and can easily be used to detect presence. You just need to read the BFI data (its plaintext) and if it changes, you can track wherever the smartphone the beam is now pointing towards. Detecting exactly who is another feature but in general, WiFi technologies are insecure and easily available as surveillance devices.
bethekidyouwant
I’m not understanding this. You still have to deploy a piece of hardware to read the Wi-Fi waves. Why wouldn’t you just deploy some other piece of hardware that’s better at surveilling the surroundings?
Also, if the Wi-Fi device is in the area are not busy now your camera is off that doesn’t seem good. Also, I imagine you have to tune it for every environment, geometry that doesn’t sound easy. And then after all that work, I move my Wi-Fi router 4 inches to the left.
show comments
bethekidyouwant
I’m not understanding this. You still have to deploy a piece of hardware to read the Wi-Fi waves. Why wouldn’t you just deploy some other piece of hardware that’s better at surveilling the surroundings?
Also, if the Wi-Fi device is in the area are not busy now your camera is off that doesn’t seem good. Also, I imagine you have to tune it for every environment, geometry that doesn’t sound easy.
bethekidyouwant
I’m not understanding this. You still have to deploy a piece of hardware to read the Wi-Fi waves. Why wouldn’t you just deploy some other piece of hardware that’s better at surveilling the surroundings?
Also, if the Wi-Fi device is in the area are not busy now your camera is off that doesn’t seem good
bethekidyouwant
I’m not understanding this. You still have to deploy a piece of hardware to read the Wi-Fi waves. Why wouldn’t you just deploy some other piece of hardware that’s better at surveilling the surroundings?
josefritzishere
There is no could. This is a turnkey function for any modern managed wifi system right now.
show comments
firecall
This reads like proper science fiction tech!
october8140
Can we make WiFi 2 that doesn’t let people do this?
show comments
AndrewKemendo
“Could become”
Already is and widely used for exactly what the article worries about
This is a VERY controlled environment - and they used 20 passes of each person walking with direct knowledge of each person to train for identity. They did no tests with multiple people walking at the same time, or with any other external moving distortion effects (doors opening, etc) . This is very far from actual 'identification' of people in real public settings - and no doubt the cell phone everyone is carrying with them offers many orders of magnitude better opportunity. In a real crowded environment this would be nearly worthless.
The devices that reported BFI information were also stationary, and there were no extra devices transmitting information that would be conflicting.
A single camera would be much more effective.
Not sure how many people are aware that the newer Alexa devices have "presence detection" that uses ultrasound so they can detect when people are nearby. [0]
Heck, even Ecobee remote temperature sensors can do this.
Reminds me of the story about how the Google Nest smoke detector had a microphone in it. [1]
0 - https://www.amazon.com/b?node=23435461011&tag=googhydr-20&hv...
1- https://www.reddit.com/r/privacy/comments/asmusq/google_says...
> The method takes advantage of normal network communication between connected devices and the router. These devices regularly send feedback signals within the network, known as beamforming feedback information (BFI), which are transmitted without encryption and can be read by anyone within range.
> By collecting this data, images of people can be generated from multiple perspectives, allowing individuals to be identified. Once the machine learning model has been trained, the identification process takes only a few seconds.
> In a study with 197 participants, the team could infer the identity of persons with almost 100% accuracy – independently of the perspective or their gait.
So what's the resolution of these images, and what's visible/invisible to them? Does it pick up your clothes? Your flesh? Or mosty your bones?
Correct me if I'm wrong but assuming they didn't already know your identity, wearing a mask for instance would prevent profiling you based on your radio wave constructed facial features.
Android devices already know exactly where they are even with GPS disabled, because they sniff the nearby WIFI networks and then ask Google where they are. QED Google knows already, all combined is mass metadata surveillance already provided to those that tap into it.
Any sub-meter precision or presence detection does not really matter, if these companies have all your other questions, queries, messages, calendars, browse history, app usage, and streaming behaviour as well.
This "could become" sounds exactly like when you look at a cool robotics project, and when you ask the researcher what it could be used for, they say "it could be used for search & rescue after a natural disaster".
The truth is that it's cool research that currently has zero use-case. But a) journalists would not write about that and b) researchers may try to use examples to explain what their research does. Probably researchers are tempted to find a cool use-case of course, because it's better for them if journalists write about their research.
This sounds like cool research that is not remotely close to becoming an invisible mass surveillance system.
Various cheating to get their conclusions (from the paper):
> To allow for an unobstructed gait recording, participants were instructed not to wear any baggy clothes, skirts, dresses or heeled shoes.
> Due to technical unreliabiltities, not all recordings resulted in usable data. For our experiments, we use 170 and 161 participants for CSI and BFI, respectively. [out of 197]
I wish they had explained what the technical unreliabilities were.
WiFi is already part of invisible mass surveillance systems, though not in the way described in the article. It's part of how cell phones fix location, based on nearby wifi endpoints, which is then sent to google, apple, every app, every advertiser, etc.
I'm skeptical; this seems like a pretty crappy way to do surveillance. Cameras give you much more information.
Paper: https://dl.acm.org/doi/epdf/10.1145/3719027.3765062
I remember reading about this in a Cory Doctorow novel decades ago, Eastern Standard Tribe, I think.
Funny how mass surveillance concerns are popping up here and there these days. That boat sailed 20 years ago.
WiFi Could Become an Invisible Mass Surveillance System
Highly unlikely and would be a waste of effort and resources. In the real world we are already well surveilled by cameras, microphones, satellites, cell phones, televisions, modern vehicles with a large number of cameras, web enabled doorbell cameras, refrigerators, AirTags, robot vacuum cleaners that map our home and monitor us, anything bluetooth enabled and that is even before actual spy devices like laser microphones that can turn most windows into a giant microphone.
All of these methods are far more attainable without trying to recreate microwave imaging that has been used by the feds for ages and the feds use a handheld device vs. this complex lab setup and this is even before we talk about advanced high resolution milspec FLIR which some companies have managed to get into serious trouble for selling to sanctioned countries for ITAR violations.
I was really impressed that a ESP32 Antenna Array Can essentially make a WiFi camera - it uses both time and phase differences to localize based on MAC addresses (which are sent plaintext) https://www.youtube.com/watch?v=sXwDrcd1t-E
There are much better invisible mass surveillance devices like the one you carry around in your pocket every day.
You're carrying a mass surveillance system in your pants pocket
You can do it to yourself[1], I am using Tommy for presence detection in Home Assistant, works great (my house is small, so two ESP32s works fine, I am sure having 3-4 would let it see my cat breathing).
1: https://www.tommysense.com/
WiFi Sensing is part of Wi-Fi 7 and present in most recent laptops and smartphones. Local NPU machine learning can be combined with WiFI radar. Malware can attack phone and radio basebands and exploit this capability. It can uniquely fingerprint human biometrics, measure breathing rate, record keystrokes and more. Thousands of academic papers have been published in the last 15 years on "device free wireless sensing", before the capability was ratified by IEEE as 802.11bf. It's being rolled out commercially. Mitigations include drywall or insulation with a layer of RF shielding.
"Xfinity using WiFi signals in your house to detect motion", 500 comments, https://news.ycombinator.com/item?id=44426726#44427986
"Wi-fi signal tracks heartbeat without wearables", 80 comments, https://news.ycombinator.com/item?id=45488908
2022 laptop demo of respiration sensing, https://www.intel.com/content/www/us/en/research/respiration... | https://community.intel.com/t5/Blogs/Tech-Innovation/Client/...
2025 biometric signature, https://www.theregister.com/2025/07/22/whofi_wifi_identifier...
> Researchers.. developed.. a biometric identifier for people based on the way the human body interferes with Wi-Fi signal propagation.. CSI in the context of Wi-Fi devices refers to information about the amplitude and phase of electromagnetic transmissions.. interact with the human body in a way that results in person-specific distortions.. processed by a deep neural network, the result is a unique data signature.. [for] signal-based Re-ID systems
Caveat: Indoors. However, since indoors is typically a private space, the degree of surveillance depends on the owner of the space. Civilians can only compel government agencies to make sure that government buildings do not enable tracking. We won't be able to stop Walmart, they can always play the security card which trumps privacy every time.
How good is ethernet over electrical sockets these days. I had one about 15 years ago maybe, but it wasn't that good.
Has tech changed. I'd use it over my wifi setup if its was fast.
Could this be countered by wearing wire-mesh patch clothing, perhaps in randomized stylish arrangements?
Cameras just use light waves and are already a mass surveillance system.
Reminds me of the xfinity in-home wifi motion detection, discussed here: https://news.ycombinator.com/item?id=44426726
> In a study with 197 participants, the team could infer the identity of persons with almost 100% accuracy
That a super impressive! I wonder how that would be at scale, with a few millions people. I’m don’t think that would remain as accurate
Who cares, we have nothing to hide.
So, should I start walking around with a jammer or something?
I don't see how this is categorically any different from hidden networked cameras. Perhaps that's the real issue we should be focusing on in terms of privacy and mass surveillance.
Scary title, 3 month late into the party… really we don’t deserve better articles with non-dramatic content, much faster?
Xfinity does it or at least say they do.
Could? Is mate. Is.
Perhaps we should ask be using aluminium foil hat now
"As radio waves move through a space and interact with people, they create distinctive patterns that can be captured and analyzed. These patterns are comparable to images produced by cameras, but they are formed using radio signals rather than light. "
The concept sounds not unlike like the multispectral imaging produced by Geordi's visor in TNG.
Seems conceptually possible, but likely too much computing power and observing time (to build up and learn each individual's pattern in that part of the RF band), at least in current times.
I'm sure it could be developed to work in the field, but what is the use case where it pays off to make the silly-money investment to make it happen? Especially so when it's far easier to simply notice pings and get better data when approximately everyone always carries their mobile phone.
LOL @ "Could"
Nothing says "out of touch with reality" like 'murcan media.
Beamforming information is utilized for creating this surveillance. There are also a lack of configurations in common routers to turn off BFI. The BFI information is available to any WiFi snooping and can easily be used to detect presence. You just need to read the BFI data (its plaintext) and if it changes, you can track wherever the smartphone the beam is now pointing towards. Detecting exactly who is another feature but in general, WiFi technologies are insecure and easily available as surveillance devices.
I’m not understanding this. You still have to deploy a piece of hardware to read the Wi-Fi waves. Why wouldn’t you just deploy some other piece of hardware that’s better at surveilling the surroundings? Also, if the Wi-Fi device is in the area are not busy now your camera is off that doesn’t seem good. Also, I imagine you have to tune it for every environment, geometry that doesn’t sound easy. And then after all that work, I move my Wi-Fi router 4 inches to the left.
I’m not understanding this. You still have to deploy a piece of hardware to read the Wi-Fi waves. Why wouldn’t you just deploy some other piece of hardware that’s better at surveilling the surroundings? Also, if the Wi-Fi device is in the area are not busy now your camera is off that doesn’t seem good. Also, I imagine you have to tune it for every environment, geometry that doesn’t sound easy.
I’m not understanding this. You still have to deploy a piece of hardware to read the Wi-Fi waves. Why wouldn’t you just deploy some other piece of hardware that’s better at surveilling the surroundings? Also, if the Wi-Fi device is in the area are not busy now your camera is off that doesn’t seem good
I’m not understanding this. You still have to deploy a piece of hardware to read the Wi-Fi waves. Why wouldn’t you just deploy some other piece of hardware that’s better at surveilling the surroundings?
There is no could. This is a turnkey function for any modern managed wifi system right now.
This reads like proper science fiction tech!
Can we make WiFi 2 that doesn’t let people do this?
“Could become”
Already is and widely used for exactly what the article worries about
Not surprised, related: https://news.ycombinator.com/item?id=46920315