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96 comments
It's likely LLM generated
1) You can't have any moving parts on it or the seams become a slot antenna
2) Will drain your battery as it adds power to find a faraway cell tower (unless you are in airplane mode)
3) It actually does exist. It costs $1000: https://privoro.com/product-vault
2) Will drain your battery as it adds power to find a faraway cell tower (unless you are in airplane mode)
3) It actually does exist. It costs $1000: https://privoro.com/product-vault
For significantly less money, one could get these - https://www.amazon.com/Faraday-Anti-Tracking-Laptops-Firepro...
I keep backup navigation tablets on my sailboat inside of those, with the idea being that if the boat is ever neutralized by lightning, at least I'll have some backups. (I also have paper charts for most everywhere I might be.)
I keep backup navigation tablets on my sailboat inside of those, with the idea being that if the boat is ever neutralized by lightning, at least I'll have some backups. (I also have paper charts for most everywhere I might be.)
This just looks like a hard bag…wouldn’t you need to open it to use the device? I feel the goal of the suggestion was a way to hide the device while keeping it physically accessible.
The signals would be able to escape out the front of the screen, so a proper faraday cage effect would require full enclosure... since that's one of the core principles behind faraday cages.
Transparent aluminium! Or..eeeerrr...copper!? Make it happen Mr Scott!
Does turning off your phone or putting it in airplane mode provide sufficient protection against whatever attacks you are worrying about?
If your answer is yes, then you don't need a faraday cage.
If your answer is no, you are facing advanced adversary. You probably don't want a phone on you at all, faraday caged or not.
If your answer is yes, then you don't need a faraday cage.
If your answer is no, you are facing advanced adversary. You probably don't want a phone on you at all, faraday caged or not.
I mean to be fair, there's really no guarantee that something in the phone's hardware is neither sending nor receiving (and processing) signals. I agree though that if you're worried about being tracked or attacked, in most scenarios you're better off just not having the phone on your person.
If you for some reason do need one, it's important to know when you put a modern iPhone in airplane mode it disables cellular but leaves WiFi/Bluetooth enabled. When you disable WiFi/Bluetooth it just disconnects from the devices for a day, but doesn't actually fully disable these fully. You can verify by going into the settings app and seeing that the radios are still toggled on.
And even if you do _that_, I have no idea how the software actually disables the hardware, but it may not physically power off the chip.
If you for some reason do need one, it's important to know when you put a modern iPhone in airplane mode it disables cellular but leaves WiFi/Bluetooth enabled. When you disable WiFi/Bluetooth it just disconnects from the devices for a day, but doesn't actually fully disable these fully. You can verify by going into the settings app and seeing that the radios are still toggled on.
And even if you do _that_, I have no idea how the software actually disables the hardware, but it may not physically power off the chip.
Any Faraday cage, bag or not, will eliminate surveillance of the phone until it comes online. Physics wins again.
I'm no EM expert, but is it possible to have a transparent Faraday cage material that lets a capacitive touch screen register touches and be seen without any leak of radiation/data? As I understand it a big conductive finger crossing a Faraday cage breaks it quite completely, but I'm not certain of this.
Probably? Transparent -- ITO on glass is the usual answer. You can deposit the ITO in patterns rather than as a continuous layer; and a conductive layer works as a faraday cage as long as the gaps are significantly smaller than the relevant wavelength (so ~mm for mmWave). So a ~500 µm grid could be laid down on glass in front of the screen, and conductively joined to a continuously conductive layer surrounding the back of the phone. The question, then, is whether the change in capacitance from a finger is observable by the touch screen through such a mesh... my intuition is that it would be, but would have to either model it or test it to find out. (Could test with just a stainless steel mesh from the hardware store.)
But none of this helps with the "toggle-able" part of the requirements…
But none of this helps with the "toggle-able" part of the requirements…
I’d imagine you could have a grid of conductors which can be temporarily connected together (by a grid of transistors somehow?) forming a cage when connected. You’d only need this mechanism on the back of the case - note that a phone can still make calls when face down on a metal sheet.
No because your finger could operate as an antenna. You're conductive.
I think that the engineering is very challenging and the market for this is nonexistent.
First, anyone truly concerned about this for actual use cases just isn’t going to bring their phone with them at sensitive times. Especially after the infamous chip bag Italian meta data incident.
Second, it’s conspicuous and kinda suspicious so its use is limited to primarily virtue signaling privacy advocates or crazy people and the latter aren’t usually big spenders.
Third: the engineering sounds challenging. All that metal in an undeployed fashion is going to reflect and interfere with reception. ( it isn’t an iron man suit, it has to get packed somewhere.). That may also interfere with RF safety approvals? Finally, avoiding RF leakage is surprisingly difficult in practice.
First, anyone truly concerned about this for actual use cases just isn’t going to bring their phone with them at sensitive times. Especially after the infamous chip bag Italian meta data incident.
Second, it’s conspicuous and kinda suspicious so its use is limited to primarily virtue signaling privacy advocates or crazy people and the latter aren’t usually big spenders.
Third: the engineering sounds challenging. All that metal in an undeployed fashion is going to reflect and interfere with reception. ( it isn’t an iron man suit, it has to get packed somewhere.). That may also interfere with RF safety approvals? Finally, avoiding RF leakage is surprisingly difficult in practice.
> chip bag Italian meta data incident
I’m not familiar with this one and search didn’t get me anything that seemed relevant. Got a link to something describing the incident?
I’m not familiar with this one and search didn’t get me anything that seemed relevant. Got a link to something describing the incident?
The kidnapping of Abu Omar.
https://en.wikipedia.org/wiki/Abu_Omar_case
https://m.youtube.com/watch?v=BwGsr3SzCZc
https://en.wikipedia.org/wiki/Abu_Omar_case
https://m.youtube.com/watch?v=BwGsr3SzCZc
What is the chip bag Italian meta data incident?
What is the infamous chip bag Italian meta data incident? I have had a quick search but nothing obvious jumped out. I'm very curious!
I don't understand the use case. What would this provides that Airplane Mode doesn't?
The difference between physical and software controls is pretty straightforward. (Closed source) software controls are just asking politely. Physical controls are making it so.
If your threat model includes airplane mode not working as intended, you probably shouldn't carry a phone at all.
May be but corporate greed for data surveillance occasionally surpasses the needs of state actors so much that they'll voluntarily invent features on the same level.
Google/Apple can in the future announce a "safety" feature that periodically announce Airtag'ish Bluetooth beacons even when in Airplane or powered off mode.
Google/Apple can in the future announce a "safety" feature that periodically announce Airtag'ish Bluetooth beacons even when in Airplane or powered off mode.
Comes down to the model of trust as much as any threat model. I don't need to perceive or even conceive of a specific threat to want to safeguard my privacy, even aggressively if I so desire.
If the threat model includes surveillance capitalism, then the faraday cage is actually a pretty reasonable counter measure.
It blocks nfc, bluetooth and wifi. The last time I checked, airplane mode left those on, and so did the toplevel “turn this radio off” buttons in iOS.
It blocks nfc, bluetooth and wifi. The last time I checked, airplane mode left those on, and so did the toplevel “turn this radio off” buttons in iOS.
Airplane mode doesn't actually turn everything off, and it's not a guarantee like a faraday cage is. There are instances of devices still actually transmitting "stuff" in airplane mode, or having airplane mode silently disabled. A faraday cage is absolute, assuming correctly constructed, in that it guarantees zero signal can get in AND out. There's no ambiguity (again, assuming correct construction).
Wouldn’t turning the phone off accomplish the same thing?
All of the bags and boxes others have posted make the phone unusable, so turning it off seems just as well. Plus, if you leave the phone on, without airplane mode, in a faraday cage, it’s going to die rather quickly while it searches for a signal.
All of the bags and boxes others have posted make the phone unusable, so turning it off seems just as well. Plus, if you leave the phone on, without airplane mode, in a faraday cage, it’s going to die rather quickly while it searches for a signal.
Believe it or not, no - modern phones are rarely genuinely “off.” iOS has some form of “find my” that still works, I’m not sure where android’s at with it, but “off” and “not transmitting” are genuinely not the same thing at this point.
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Airplane mode doesn't turn off wifi or Bluetooth, though obviously you can do that in addition to airplane mode.
Right, the airplane icon does not necessarily.
Settings for WiFi, turn off; settings for Bluetooth, turn off; does turn them off.
This change was the result of years of supporting people meaning to turn it off in one place or one day, then confused it didn't work at home or the next day.
So now airplane mode is a conditional off (the state machine across cellular, wifi, and bluetooth is pretty decent at doing a reasonable set of toggles), while the settings are off off.
The near field stuff seems to remain available; full shutdown turns that off too.
Settings for WiFi, turn off; settings for Bluetooth, turn off; does turn them off.
This change was the result of years of supporting people meaning to turn it off in one place or one day, then confused it didn't work at home or the next day.
So now airplane mode is a conditional off (the state machine across cellular, wifi, and bluetooth is pretty decent at doing a reasonable set of toggles), while the settings are off off.
The near field stuff seems to remain available; full shutdown turns that off too.
Is that an iPhone thing? On Android airplane mode turns off both Wi-Fi and Bluetooth.
It used to turn them off on the iPhone, but not these days.
A lot of planes have WiFi, and people are also using Bluetooth headphones. So when talking about being a passenger on an airplane, this seems like a rather practical choice.
A lot of planes have WiFi, and people are also using Bluetooth headphones. So when talking about being a passenger on an airplane, this seems like a rather practical choice.
Not for my Android phone, at least not by default (Pixel 9a a/ GrapheneOS). It leaves Bluetooth and WiFi on in airplane mode. I doubt this is specific to GrapheneOS and may say more about AOSP.
That's a setting you can tweak with various software.
Not if you were connected to either when turning on airplane mode. Both can also be turned on manually in airplane mode. A physical block avoids any uncertainty or mistakes.
In theory, an APT-type implant could keep transmitting even when airplane mode is engaged. This is what Faraday enclosures purportedly defeat.
Certainty?
There are plenty of Faraday bags readily available for cell phones.
Look in the digital forensics industry. Field forensic investigators can get bags or boxes (look like Pelican(r) cases), or inserts for Pelican cases (a 1615 fits just right into a sedan's trunk).
Long time ago when mobile forensics was in its infancy they were given out as swag.
The #1 problem is of course that if not in airplane mode, some not too smart phones keep increasing the power to the radio (smarter ones do this for a few minutes then power down radio, then cycle up again). Guess what happens with a bunch of juice dumped into electronics in a locked case inside a trunk in a hot car, with half dozen other phones doing the same thing (because it is never a single burner phone).
In a pinch, 3 to 5 layers of aluminum foil, stainless steel cocktail shaker, ammo can, or combination thereof works.
edit: Yes, if we are discussing this with physicists, RF cannot be blocked, it can be attenuated. The strength of the RF signal is reduced as it travels through different materials, and in theory it can never be completely eliminated. In practicality, the signal only needs to be attenuated until it cannot be picked up sufficiently even when very close by a receiver.
Look in the digital forensics industry. Field forensic investigators can get bags or boxes (look like Pelican(r) cases), or inserts for Pelican cases (a 1615 fits just right into a sedan's trunk).
Long time ago when mobile forensics was in its infancy they were given out as swag.
The #1 problem is of course that if not in airplane mode, some not too smart phones keep increasing the power to the radio (smarter ones do this for a few minutes then power down radio, then cycle up again). Guess what happens with a bunch of juice dumped into electronics in a locked case inside a trunk in a hot car, with half dozen other phones doing the same thing (because it is never a single burner phone).
In a pinch, 3 to 5 layers of aluminum foil, stainless steel cocktail shaker, ammo can, or combination thereof works.
edit: Yes, if we are discussing this with physicists, RF cannot be blocked, it can be attenuated. The strength of the RF signal is reduced as it travels through different materials, and in theory it can never be completely eliminated. In practicality, the signal only needs to be attenuated until it cannot be picked up sufficiently even when very close by a receiver.
I came here to say what you did. I used to work in three letter agencies and took part in testing faraday bags for clandestine operators. Something about faraday bags that most people don't know is that they have a shorter life than you would think. As they move around and bend, they start to "leak" more RF. WaitWaitWha is also correct that in a pinch, some aluminum foil works pretty well if you're careful. The service will be so bad, that the phone won't likely get packets out or in. Just be thorough when doing it.
Also, I worked with clandestine people and for most of them had threat models more relaxed than a lot of people on HN. What are you all up to???
Also, I worked with clandestine people and for most of them had threat models more relaxed than a lot of people on HN. What are you all up to???
You don't need a form fitting faraday cage. Want a free one? Find a food delivery bag that is insulated with foil. I believe some of the meal prep delivery services package their groceries in this. Stick your phone in there and wrap it up. All signals gone as far as I can tell.
Or, even more free or cheap: Wrap it in aluminum foil.
Or, even more free or cheap: Wrap it in aluminum foil.
Just electroless plate the interior of something like this [0]? Or use conductive paint if the polyurethane doesn't take an electroless well. Don't know what OEM Nillkin uses but I'm sure the factory has iPhone cases as well.
[0] https://www.amazon.com/Nillkin-Samsung-Leather-Magnetic-Prot...
Edit: Oh, missed the "toggle on/off without removing the device." Nah, that's not a thing that's going to work. Even with the flap open you'll be attenuating enough RF through the back that either you won't have a decent connection, or your battery life will be crap.
[0] https://www.amazon.com/Nillkin-Samsung-Leather-Magnetic-Prot...
Edit: Oh, missed the "toggle on/off without removing the device." Nah, that's not a thing that's going to work. Even with the flap open you'll be attenuating enough RF through the back that either you won't have a decent connection, or your battery life will be crap.
You wouldn’t be able to use a Faraday case. The physics principle behind it requires it to surround the whole device which is being shielded.
The iPhone antennagate story would suggest that sometimes this isn’t the situation.
A faraday cage is different than your hand attenuating your phone signal
Attenuating RF is exactly what a Faraday cage does.
Though as you suggest, relying that would be a bad idea.
For some reason manually turning off RF transmission seems to have been ruled out, so we are looking for an unusual solution to the problem.
Though as you suggest, relying that would be a bad idea.
For some reason manually turning off RF transmission seems to have been ruled out, so we are looking for an unusual solution to the problem.
I'm curious how you'd plan the toggling to work. It'd have to be foldable at minimum to be able to wrap around and over the screen. But I'd imagine just having a folded back faraday shield on the back of the phone would tank network performance no?
Maybe this is a dumb comment, but couldn’t you just turn the phone off? You’d have to trust that the setting to disable Bluetooth when powered down is reliable and configured correctly, but if your use case is that sensitive even carrying a smartphone seems questionable.
No; if a phone has both a non-removable battery and a baseband modem, then various laws require that modem to be wired directly to that battery (and to the phone's microphone) and to able to be activated in response to a legal wiretap order, even when the phone itself is nominally "powered off."
(And this doesn't even require that the phone stay connected to the network after the wiretap-enable packet is received. Rather, while the phone is "powered off", the baseband modem might sit there passively acting as a bug, capturing conversation through the microphone onto a bit of NAND onboard the modem; and then, once the phone is powered on again, the baseband modem will take the opportunity to silently play back whatever it's recorded to the tower.)
> if your use case is that sensitive even carrying a smartphone seems questionable.
The issue is that, if you're an actual honest-to-god spy (or investigative journalist...) trying to poke their nose into the goings-on of some government, then you want to draw as little suspicion to yourself as possible; and it's much more suspicious to be going around without the subject government's favorite citizen-surveillance tool on your person. In fact, to blend in, you need to be constantly using your state-surveillance-device to communicate with (decoy) friends and coworkers, doom-scroll, etc.
This is why spies are fans of the few remaining Android phone brands that offer designs with removable batteries. When meeting with a contact, they'll still slip their could-be-bugged-phone into a faraday bag, to cut off its network connectivity; but they'll also remove the phone's battery before putting the phone into the faraday bag, to inhibit this class of "powered-off" record-to-NAND-style baseband wiretap attacks.
(Of course, these are just ways to secure a phone you own + can determine wasn't subject to a supply-chain attack. If two people are meeting who aren't within the same security envelope, then either of them might be trying to surreptitiously record the conversation, and so their phones (or anything else on them) might contain a tiny bug with its own power source, that would stay active even if the macro-scale device's battery was removed. For such meetings, you therefore want to leave all electronic devices in a soundproof safe, in another room. Which will also implicitly act as a faraday cage.)
(And this doesn't even require that the phone stay connected to the network after the wiretap-enable packet is received. Rather, while the phone is "powered off", the baseband modem might sit there passively acting as a bug, capturing conversation through the microphone onto a bit of NAND onboard the modem; and then, once the phone is powered on again, the baseband modem will take the opportunity to silently play back whatever it's recorded to the tower.)
> if your use case is that sensitive even carrying a smartphone seems questionable.
The issue is that, if you're an actual honest-to-god spy (or investigative journalist...) trying to poke their nose into the goings-on of some government, then you want to draw as little suspicion to yourself as possible; and it's much more suspicious to be going around without the subject government's favorite citizen-surveillance tool on your person. In fact, to blend in, you need to be constantly using your state-surveillance-device to communicate with (decoy) friends and coworkers, doom-scroll, etc.
This is why spies are fans of the few remaining Android phone brands that offer designs with removable batteries. When meeting with a contact, they'll still slip their could-be-bugged-phone into a faraday bag, to cut off its network connectivity; but they'll also remove the phone's battery before putting the phone into the faraday bag, to inhibit this class of "powered-off" record-to-NAND-style baseband wiretap attacks.
(Of course, these are just ways to secure a phone you own + can determine wasn't subject to a supply-chain attack. If two people are meeting who aren't within the same security envelope, then either of them might be trying to surreptitiously record the conversation, and so their phones (or anything else on them) might contain a tiny bug with its own power source, that would stay active even if the macro-scale device's battery was removed. For such meetings, you therefore want to leave all electronic devices in a soundproof safe, in another room. Which will also implicitly act as a faraday cage.)
> if a phone has both a non-removable battery and a baseband modem, then various laws require that modem to be wired directly to that battery (and to the phone's microphone) and to able to be activated in response to a legal wiretap order, even when the phone itself is nominally "powered off."
Could you link to such a law?
Could you link to such a law?
I have seen phone schematics for many generic Androids, and at least for them, this comment is complete BS. The AP loads the firmware for the modem when it's turned on and boots it, and completely powers off the modem when asked to turn it off, e.g. in airplane mode. No idea about Apple though, they tend to Think Different™.
> I have seen phone schematics
Documentation is insufficient for protection.
Stuxnet happened, despite correct documentation of Siemens PLCs.
Documentation is insufficient for protection.
Stuxnet happened, despite correct documentation of Siemens PLCs.
That is a complete non-sequitur.
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And camera slider cases are privacy theater. If somehow someone activated your camera remotely, don’t you think they could also activate your microphone, and your GPS?
Everything is theater if one is cynical enough. One can very obviously find value in blocking the camera, even if other sensors remain active.
That said, I do see merit to flagging these. Related surprises are usually e.g. speakers being possible to use as microphones, and accelerometer data being possible to use for location tracking in lieu of GPS / any kind of radio, just not remotely & live ofc.
That said, I do see merit to flagging these. Related surprises are usually e.g. speakers being possible to use as microphones, and accelerometer data being possible to use for location tracking in lieu of GPS / any kind of radio, just not remotely & live ofc.
What value is there in blocking a camera if the microphone isn’t blocked? No one can glean anything from the camera in my pocket or face down (or up) on table - they ca. glean a lot from the microphone
Have you ever been nude?
Not with my phone camera propped up where it can see me…
And if anyone wanted to look at my 51 year old body I think I would take that as complement.
And if anyone wanted to look at my 51 year old body I think I would take that as complement.
> Not with my phone camera propped up where it can see me…
Like held in your hand? Quickly checking something mid-dressing? Or on the toilet?
Like held in your hand? Quickly checking something mid-dressing? Or on the toilet?
And why would I have my phone in a position when I am nude that anyone could see anything but my face? While I’m in decent shape, if I lost my job I won’t be opening an OnlyFans account
Couldn’t you just turn off wifi, cellular data and bluetooth?
The question was hard for me to parse; I want to carry with me a snitch, but remove its ability to snitch, but be able to restore it's ability to snitch?
My approach is; how do avoid the snitch? I just leave my phone in the car or at home.
My approach is; how do avoid the snitch? I just leave my phone in the car or at home.
Start a viral campaign for iphone with mechanical switches
Stupid question: can't you just turn it off? Does it emit signals / identifying information while it's off?
It says it's off. You're a journalist reporting against a fascist regime. You, your family, and known associates will be tortured and killed if you are found. Do you trust it, or a mesh wire lined bag that physics says definitely will block it?
The regime will then just look through the transaction history of the faraday cage merchant and execute the five dollar wrench attack on every person who bought one.
Realistically, if your adversaries are capable of communicating with your phone while it's turned off or in airplane mode, your best solution is probably just to hit your phone with a five dollar wrench until it breaks.
Realistically, if your adversaries are capable of communicating with your phone while it's turned off or in airplane mode, your best solution is probably just to hit your phone with a five dollar wrench until it breaks.
I feel like if those are the stakes I'd be better off leaving it behind.
Funny that this is a non-existent problem for the previous generation of phones, since they had removable battery.
The Faraday effect can't really be toggled except by physically compromising the enclosure, i.e. opening the Faraday cage/pouch and removing the device. Your "Faraday case" wouldn't be meaningfully more convenient than a pouch or other enclosure.
> Faraday bags exist (SLNT, Mission Darkness, etc.) - they block all RF signals
They really don’t. “Blocking” RF really isn’t a thing. RF can be attenuated, but it is quite a complicated problem to solve. Have you tried any of these bags?
They really don’t. “Blocking” RF really isn’t a thing. RF can be attenuated, but it is quite a complicated problem to solve. Have you tried any of these bags?
Way back in the flip phone days, I had evil tracking software on my corpo phone for a time.
I didn't mind that they knew where I was when I was being paid, but I had issues with abuse by one particular manager (who was more my equal than my boss, but nevermind that).
This tracking software could be disabled with a couple of button pushes, or the phone simply turned off, but these action generated alerts that were sent home to the mothership. I did not like this aspect at all.
So I bought a little Faraday bag from somewhere in China -- back then, probably from DealExtreme. It fit the phone so well that it seemed like it must have been made for that specific model (even though it almost certainly was not). Inside, it had two compartments: One that encapsulated the device well-enough with conductive fabric, and another that was outside of (and adjacent to) that envelope, which just protected the phone from things like incidental abrasions.
I used it as an every-day phone case. When I wanted the phone to work, I used the non-shielded part. If I wanted the phone to not work, then I used the shielded compartment instead.
In imprecise practical terms, this bag blocked successful RF communications. (And I knew this to be true, because I also had access to the mothership's web interface and could review the tracking data for myself and my coworkers.)
---
I can accept that "blocked" is not the most-precise term. In a way that is similar to many other things, a valid and accurate technical description of what was achieved would require additional precision.
But such precision is not always necessary in order to succinctly have words convey their desired intent, and I don't think it's required here for OP's intent to be understood.
I didn't mind that they knew where I was when I was being paid, but I had issues with abuse by one particular manager (who was more my equal than my boss, but nevermind that).
This tracking software could be disabled with a couple of button pushes, or the phone simply turned off, but these action generated alerts that were sent home to the mothership. I did not like this aspect at all.
So I bought a little Faraday bag from somewhere in China -- back then, probably from DealExtreme. It fit the phone so well that it seemed like it must have been made for that specific model (even though it almost certainly was not). Inside, it had two compartments: One that encapsulated the device well-enough with conductive fabric, and another that was outside of (and adjacent to) that envelope, which just protected the phone from things like incidental abrasions.
I used it as an every-day phone case. When I wanted the phone to work, I used the non-shielded part. If I wanted the phone to not work, then I used the shielded compartment instead.
In imprecise practical terms, this bag blocked successful RF communications. (And I knew this to be true, because I also had access to the mothership's web interface and could review the tracking data for myself and my coworkers.)
---
I can accept that "blocked" is not the most-precise term. In a way that is similar to many other things, a valid and accurate technical description of what was achieved would require additional precision.
But such precision is not always necessary in order to succinctly have words convey their desired intent, and I don't think it's required here for OP's intent to be understood.
Maybe it worked with less sensitive radios back in the day.
I have done experiments on recent devices and it’s very difficult. I was successful in attenuating cell service with a $XXXX test enclosure, but not 2.4Ghz WiFi.
Maybe blocking cell service is good enough for your use case, but if you’re trying to protect against an APT you’re probably half-way closing the vulnerability.
I have done experiments on recent devices and it’s very difficult. I was successful in attenuating cell service with a $XXXX test enclosure, but not 2.4Ghz WiFi.
Maybe blocking cell service is good enough for your use case, but if you’re trying to protect against an APT you’re probably half-way closing the vulnerability.
So they don’t effectively block communication to and from the device? Or they don’t block all RF? Because the former seems to qualify as working, while the latter seems irrelevant. Or the only sometimes block communication to/from the device?
It is only irrelevant because devices made in this century put a lot of work into not transmitting outside of the intended frequencies.
My old Nokia would smash the whole range of AM/FM and UHF bands.
I don't know about higher frequencies that could escape one of these cages intended to block WiFi/5G/GPS but it is possible in theory and then it would be likely a backdoor that only becomes active when no signal can be detected.
My old Nokia would smash the whole range of AM/FM and UHF bands.
I don't know about higher frequencies that could escape one of these cages intended to block WiFi/5G/GPS but it is possible in theory and then it would be likely a backdoor that only becomes active when no signal can be detected.
> So they don’t effectively block communication to and from the device?
That is impossible to know without knowing the characteristics of the signal, noise, attenuation performance, sensitivity of the receiver, and other environmental conditions.
> Or they don’t block all RF?
They definitely don’t.
If you want to attenuate an RF signal, you need to do RF engineering. There are products to help people do this (eg RF test enclosure), but they aren’t marketed as “blocking RF” because that is nonsensical. The products that advertise as “blocking RF” without any real specifications are unsuitable for serious RF engineering, they are primarily sold to conspiracy theorists, hypochondriacs, etc.
That is impossible to know without knowing the characteristics of the signal, noise, attenuation performance, sensitivity of the receiver, and other environmental conditions.
> Or they don’t block all RF?
They definitely don’t.
If you want to attenuate an RF signal, you need to do RF engineering. There are products to help people do this (eg RF test enclosure), but they aren’t marketed as “blocking RF” because that is nonsensical. The products that advertise as “blocking RF” without any real specifications are unsuitable for serious RF engineering, they are primarily sold to conspiracy theorists, hypochondriacs, etc.
>> So they don’t effectively block communication to and from the device?
> That is impossible to know without knowing the characteristics of the signal
Do you dispute that de facto these products work?
> That is impossible to know without knowing the characteristics of the signal
Do you dispute that de facto these products work?
Yes I have spent thousands of dollars and months testing them.
You can cut off GPS and high frequency cell spectrum pretty easily. Most cell spectrum is effectively attenuated by good quality professional RF enclosures designed for those frequencies. 2.4 ghz signals like wifi (with good quality radios) are hard to attenuate to the point where they can’t connect to other radios nearby, even with very expensive RF test enclosures.
If you’re trying to block against an unknown threat you are fucked. If someone wanted to back door a baseband they’d probably make it transmit at low speeds and low frequencies to be resistant to attenuation.
You can cut off GPS and high frequency cell spectrum pretty easily. Most cell spectrum is effectively attenuated by good quality professional RF enclosures designed for those frequencies. 2.4 ghz signals like wifi (with good quality radios) are hard to attenuate to the point where they can’t connect to other radios nearby, even with very expensive RF test enclosures.
If you’re trying to block against an unknown threat you are fucked. If someone wanted to back door a baseband they’d probably make it transmit at low speeds and low frequencies to be resistant to attenuation.
What kind of RF can travel through a few mm of metal?
If you blindly “put metal around” an antenna, most of the time, you have just created another antenna!
Go put a phone in a filing cabinet and call it. It will ring.
Go put a phone in a filing cabinet and call it. It will ring.
Jesus. That sucks. Thanks for sharing, fascinating stuff.
I will, I've got two and neither one can shut off a longwave FM radio.
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Because even though insane cranks are like 45% of HN they aren't a large enough customer base to move markets.
Can’t wait to hear from them: “I’d pay at least $5, maybe even $6 for this. I think you’re onto something critical for privacy.”
It's funny how many people here insist that nation state adversaries are out to get them.
Way too niche, and hard to get right (if there's a gap and some radio waves escape, you just transferred megabytes!). Plus it requires a metal front flap to really work.
Who is concerned about privacy, but only when their phone is in their pocket?
Just use grapheneOS or calyxOS or postmarketOS or whatever.
Just use grapheneOS or calyxOS or postmarketOS or whatever.
> Camera slider cases exist (Spy-Fy, etc.) - they block physical camera access
Do they block the front camera? I’ve only seen one case that even attempted to block it, and it was kind of flimsy and would uncover the front camera when you took it out of your pocket.
Plus you can’t block the front camera very well without impacting facial recognition.
(puts on tin-foil hat) and you’ll notice that all new models only support facial recognition and no longer offer fingerprint unlock.
Do they block the front camera? I’ve only seen one case that even attempted to block it, and it was kind of flimsy and would uncover the front camera when you took it out of your pocket.
Plus you can’t block the front camera very well without impacting facial recognition.
(puts on tin-foil hat) and you’ll notice that all new models only support facial recognition and no longer offer fingerprint unlock.
My phone with case fits into my 10 year SLNT bag?
It's all over reddit to a tiresome degree, and increasing in Ask HNs as well, generally from new accounts (as of now, the OP account is green).
They all go like this:
---
I've been doing this thing, and noticed stuff.
"The gap seems real"
"The use case seems obvious"
"So my question to the community is:"
- product/market fit bullets
Re-assertion of being just "curious".
"Happy to" [market to you more] "if you're interested".
---
Who wrote the original structure? What is everyone using to generate this same form over and over?
(I could image it being one of those "$900 to learn this one cool trick" SEO influencers, maybe SaaS-ified into one of those custom GPTs? It is shockingly effective at driving engagement -- nerd sniping the genuinely helpful?)
Is there a way to filter these out?