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Using Aluminum Oxide Paint To Secure Wi-Fi

Soulskill posted about 5 years ago | from the prank-possibilities-abound dept.

Security 271

eldavojohn writes "The BBC reports on people using aluminum oxide in their paint to block Wi-Fi signals from leaving their home or business. Aluminum oxide resonates at the same frequency as Wi-Fi signals and other radio waves, blocking data from going outside a building. It's not a flawless solution, as it may also block AM/FM signals. You or your neighbors may be unwittingly using this already, as most pre-finished wood flooring uses aluminum oxide as a protective coating."

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Cellphone reception? (4, Interesting)

beef curtains (792692) | about 5 years ago | (#29595115)

Wouldn't keeping radio signals in also have the unfortunately side effect of keeping radio signals out? While having a neighborhood coffee shop offer free wifi to paying customers while being an of oasis of cellphone-free peace & quiet would be sweet, having no cellphone reception at home because one desperately wants to prevent neighbors from stealing one's wifi seems very inconvenient (especially when setting up even the most basic built-in wireless router security would successfully do the trick in 99.9% of cases).

Re:Cellphone reception? (2, Informative)

RobVB (1566105) | about 5 years ago | (#29595303)

Wifi works at around 2.4 Ghz, GSM frequencies [wikipedia.org] are between 380 Mhz and 2 Ghz, with the most frequently used frequencies being GSM900 (890-960 Mhz) and GSM1800 (1710-1880 Mhz).

From the article:

The paint contains an aluminium-iron oxide which resonates at the same frequency as wi-fi - or other radio waves - meaning the airborne data is absorbed and blocked.

I assume this means the aluminium-iron oxide resonates at around 2400 Mhz, which shouldn't interfere with normal cell phones.

Re:Cellphone reception? (5, Informative)

morgan_greywolf (835522) | about 5 years ago | (#29595405)

Try reading more carefully:

FTFA:

While paints blocking lower frequencies have been available for some time, Mr Ohkoshi's technology is the first to absorb frequencies transmitting at 100GHz (gigahertz). Signals carrying a larger amount of data - such as wireless internet - travel at a higher frequency than, for example, FM radio.

...

"Our current mobile phones work at much lower frequencies, around 1.5 gigahertz. But, our material can also absorb frequencies that low, so you could block phone signals from outside and stop people's phones ringing during the movie," he said.

From the sounds of it, just about anything below 100 GHz gets blocked. That means cellphones, too.

Re:Cellphone reception? (1)

RobVB (1566105) | about 5 years ago | (#29595533)

"Our current mobile phones work at much lower frequencies, around 1.5 gigahertz. But, our material can also absorb frequencies that low, so you could block phone signals from outside and stop people's phones ringing during the movie," he said.

They said "can" and "could", not "does" and "will". There might be a switch. Or even different versions, which I guess makes a little more sense.

Re:Cellphone reception? (1)

morgan_greywolf (835522) | about 5 years ago | (#29595649)

They said "can" and "could", not "does" and "will". There might be a switch. Or even different versions, which I guess makes a little more sense.

Yeah, that's kinda what I'm on about, just doing it in a roundabout way. I'm no physicist, but it doesn't seem to be that a *single* RF absorbing paint could block everything from 1 Mhz-100 GHz, or even 1.5 GHz - 200 GHz. That's just too many frequencies for something like paint. 1 foot thick lead vault, okay, but paint? Mmmmmm...let's just say I kinda doubt it.

Re:Cellphone reception? (1, Interesting)

Anonymous Coward | about 5 years ago | (#29596037)

You are no physicist. Metalized paint can form a Faraday Cage. http://en.wikipedia.org/wiki/Faraday_cage

Re:Cellphone reception? (1)

morgan_greywolf (835522) | about 5 years ago | (#29596237)

Neither are you. A shopping bag lined with foil can act as a Faraday cage as well, but that still doesn't mean it's going to be effective against a wide range of frequencies, and certainly not against signals that are very powerful. From the article you quote:

The effectiveness of a Faraday cage or shield is dependent upon the wavelength of the electric or electromagnetic fields it is intended to shield. Effectiveness of shielding also depends upon the types of metals used in the cages as well as their thicknesses.

This guy in TFA makes it sound as if all I'd have to do to stop a radio station from transmitting is paint their tower with his paint.

Somehow, I doubt that's going to work.

Re:Cellphone reception? (0)

Anonymous Coward | about 5 years ago | (#29596651)

This guy in TFA makes it sound as if all I'd have to do to stop a radio station from transmitting is paint their tower with his paint.

Painting the tower won't do anything because the tower only supports the antenna. And neither would painting the antenna. You could think of an antenna as a metal antenna with a thin metal paint on it if you want to.

Re:Cellphone reception? (2, Interesting)

Forge (2456) | about 5 years ago | (#29596243)

The paint could also provide some much-needed relief during nights out at the cinema.

Our largest local movie theater installed an electronic cellphone signal blocker some years ago. It worked very well and almost put them out of business.

You see people on call (like Sysadmins, Doctors etc...) and people who feel a need to be reached on short notice for personal reasons (parents of small children), no longer saw that theater as an option for dates. This might not be a problem in some places but because of the lower pay scales (and hence higher relative cost of movie tickets) here, those affected were a major proportion of the theater's customer base.

In short they had to turn off the signal blocker and announce to disgruntled customers that it's ok to come back.

I am trying to imagine the dilemma if they had used this Aluminum Oxide paint instead, how much would it cost them to scrape it all off?

Re:Cellphone reception? (1)

wastedlife (1319259) | about 5 years ago | (#29596463)

This is why having a posted "keep cellphones off or vibrate only" rule is much better than active or even passive signal blocking. Granted, there will still be a few assholes that do not follow this, but thats where you exercise your right to kick them out.

IAAFLMTE (I am a former local movie theater employee).

Also, people who try to bring small children into a Rated R feature need to die in a fire. Its not because we care how about shitty of a parent you are, other patrons do not want a screaming kid while they enjoy a film. Save it for Spy Kids 15 </rant>

Re:Cellphone reception? (1)

AndrewNeo (979708) | about 5 years ago | (#29596673)

Someone brought their kid to the opening weekend showing of 300. I'll let you guess which scene the mom ended up taking her child out at (hint: it was early on)

Re:Cellphone reception? (2, Insightful)

NeverVotedBush (1041088) | about 5 years ago | (#29596723)

Our largest local movie theater installed an electronic cellphone signal blocker some years ago. It worked very well and almost put them out of business.

Was this in the USA? The reason is that doing this, while so very nice to prevent the idiots who don't know how to put their phones on vibrate from bothering everyone else, is also highly illegal.

The reason is that it can interfere with emergency calls even outside the building. The FCC can impose fines on the order of thousands of dollars per day that such a system is active.

There are moves afoot to try to get special exemptions to jam cell phone communications (prisons are another example) but so far it is still very illegal to run a jammer in the USA.

Re:Cellphone reception? (3, Informative)

sunderland56 (621843) | about 5 years ago | (#29596815)

The reason is that it can interfere with emergency calls even outside the building.

Actually the primary reason that jammers are illegal is that they are unlicensed. All unlicensed transmitters are illegal in the USA.

There is also a section of the FCC rules that prohibits interference in most cases, and absolutely prohibits willful interference.

Re:Cellphone reception? (1)

Cley Faye (1123605) | about 5 years ago | (#29596777)

There is another issue; blocking cellphones also ban emergency calls.
Granted, in a theater there might be other way to call for help, but locking out security for some peace while looking at a movie doesn't sound good to me.

Re:Cellphone reception? (1)

mbone (558574) | about 5 years ago | (#29595505)

They said it, but I have to wonder. Resonant generally means you have a dimension of order a wavelength. The paint particles are much smaller than the wavelength, so it sounds to me as if they are simply building a Faraday Cage, but with metallic paint, not aluminum foil or metal sheeting.

Note, if you are going to do this, you need to avoid holes the size of a wavelength / 4 or bigger - a few cm for WiFi (12 cm waves). If you like windows you should also put a fine wire mesh on them.

Re:Cellphone reception? (1)

PIBM (588930) | about 5 years ago | (#29595571)

And that's called a mosquito screen -- just make sure not to get one in plastic.

Re:Cellphone reception? (1)

zippthorne (748122) | about 5 years ago | (#29596735)

You can get them in aluminum or fiberglass. Plastic is not standard.

Re:Cellphone reception? (1, Interesting)

pz (113803) | about 5 years ago | (#29595785)

They said it, but I have to wonder. Resonant generally means you have a dimension of order a wavelength. The paint particles are much smaller than the wavelength, so it sounds to me as if they are simply building a Faraday Cage, but with metallic paint, not aluminum foil or metal sheeting.

Note, if you are going to do this, you need to avoid holes the size of a wavelength / 4 or bigger - a few cm for WiFi (12 cm waves). If you like windows you should also put a fine wire mesh on them.

Funny thing about electromagnetic resonance. The wavelength in vacuum / free air matters only ... in vacuum / free air. The wavelength of a signal in a different medium, with presumably different dielectric constant and impedance will be ... different! Water molecules are famously resonant at 2.45 GHz, that's where microwave ovens operate, despite the vacuum wavelength of 2.45 GHz photons being about 12 cm. The inter- and intra-molecular impedance makes H2O absorb those photons quite well. Water is quite rather opaque at those frequencies, despite being transparent at higher frequencies, say in the visible spectrum, and despite individual H2O molecules being many orders of magnitude smaller than the vacuum wavelength of 2.54 GHz photons.

Futhermore, bear in mind that aluminum oxide is not at all like aluminum. First off, it's an oxide. It's not a metal. It's a quite good insulator, and is used as a common abrasive because of its hardness. With impurities to give it color, it is the primary ingredient in sapphires and rubies. Coating something with aluminum oxide won't create a Faraday cage, but according to the news item, will provide a certain level of frequency-specific shielding.

Re:Cellphone reception? (3, Informative)

Geoffrey.landis (926948) | about 5 years ago | (#29596141)

Water molecules are famously resonant at 2.45 GHz, that's where microwave ovens operate,

No, they're not. That's a myth [vias.org] . There's no water resonance at or near 2.45 GHz. Water absorbs at pretty much any microwave frequency, with stronger absorption the higher the frequency.

If anything, you'd want to tune a microwave oven away from strong water resonances, because you want the radiation to penetrate (so as to heat the object evenly) and not be shallowly absorbed, which would result in uneven heating. (Note that a microwave oven is a cavity, so you don't need to absorb energy in a single pass-- it will resonate around until it does get absorbed.).

Re:Cellphone reception? (4, Insightful)

Man On Pink Corner (1089867) | about 5 years ago | (#29596213)

Funny thing about electromagnetic resonance. The wavelength in vacuum / free air matters only ... in vacuum / free air. The wavelength of a signal in a different medium, with presumably different dielectric constant and impedance will be ... different! Water molecules are famously resonant at 2.45 GHz, that's where microwave ovens operate, despite the vacuum wavelength of 2.45 GHz photons being about 12 cm. The inter- and intra-molecular impedance makes H2O absorb those photons quite well. Water is quite rather opaque at those frequencies, despite being transparent at higher frequencies, say in the visible spectrum, and despite individual H2O molecules being many orders of magnitude smaller than the vacuum wavelength of 2.54 GHz photons.

Helpful hint for posters: if you don't know a damned thing about physics, don't answer questions as if you do.

Helpful hint for moderators: if you don't know a damned thing about physics, don't mod up posts full of word-salad wharrgarbl like "intra-molecular impedance."

http://www.howeverythingworks.org/prints.php?topic=microwave_ovens&page=4 [howeverythingworks.org]

Re:Cellphone reception? (3, Interesting)

pz (113803) | about 5 years ago | (#29596599)

I stand corrected on the water resonance part.

The impedance part, well, perhaps Mr. Pink Corner needs to understand more where resistance comes from. The reason that microwave ovens work at all is that there is a resistive (ie dissipative, lossy, real, call it what you will) component to the impedance of water at those frequencies, dissipating EM energy into heat. Here's a quote from the nicely informative link Mr. Pink Corner provided:

Rather than interacting with the water molecules via a resonance, the microwaves in an oven heat the water by twisting its molecules rapidly back and forth so that they rub against one another. The molecules are heated by the molecular equivalent of sliding or dynamic friction. The choice of 2.45 gigahertz gives the water molecules about the right amount of time to twist in each direction. The precise frequency isn't important, but microwave ovens are required to operate at exactly 2.45 gigahertz so that they don't interfere with communication systems using nearby frequencies.

And here's another clue about physics, Mr. Pink Corner, when you have a complex impedance, like an RC circuit in a lumped model system, the speed of light through those components is determined by the RC time constant. The speed of light is slowed by the reactive portion of the impedance. In that system. Otherwise the movement of the current would not be impeded and the full voltage would appear at the far side of the C element instantaneously. But it does not: the speed of propagation is slowed, as reflected in the time constant. This becomes especially evident when you look at transmission lines and the impedance of the line determines the propagation speed (as well as the line loss due to heating of the real component of the impedance). Same thing in water, except, as I've been corrected, there is no resonance at 2.45 GHz.

Re:Cellphone reception? (1)

jeffmeden (135043) | about 5 years ago | (#29595517)

So "other radio waves" means "only the rest of the ones at 2.4ghz"? It even states in the summary that it "may block AM/FM signals" which are WAY below anything used by a cellphone. From the sound of the article, they are interested in blocking the widest range possible, with the researcher boasting about blocking all frequencies up to 200 GHz. Add to that the tendency of cellphones to use a LOT less transmit power and reception attenuation than typical Wi-Fi hardware, and it sounds a lot like this would certainly be an issue for cellphones.

Re:Cellphone reception? (3, Informative)

elashish14 (1302231) | about 5 years ago | (#29595671)

A conductive metal has free electrons which will block and reflect any waves below its plasma frequency. However, an ionic solid does not have free electrons - instead, it has just a few resonant other mechanisms with limited range so it will block a more specific part of the electromagnetic spectrum than a metal would. The frequency of wifi signals happens to be in the range of one of these mechanisms for the paint used.

Re:Cellphone reception? (0)

Anonymous Coward | about 5 years ago | (#29595331)

Does this wreck mobile phone signals? My understanding is that phones and wifi are in different parts of the radio spectrum?

Extra protection? (5, Funny)

BadAnalogyGuy (945258) | about 5 years ago | (#29595159)

I'm already using aluminum foil lining in many of my hats and clothes to protect me from the government transmissions. However, I hadn't heard that Al2O3 was any better than straight aluminum foil.

It seems suspicious that this story would be posted immediately after I began considering papering my walls with foil.

Re:Extra protection? (3, Interesting)

ColdWetDog (752185) | about 5 years ago | (#29595309)

May not be better but it could be more, how shall we say, stylish. Maybe quieter as well. I do like his pandering to the 'think of the children' racket.

"We're assuming that excessive exposure could be bad for us. Therefore we're trying to make protective clothes for young children or pregnant women to help protect their bodies from such waves."

Give me a break. Next think he'll be trying to create is an Aluminum oxide / silver dip - keep away nasty radio waves and germs, all in one toxic package.

I think this guy is mostly looking for some investors.

Re:Extra protection? (4, Insightful)

MozeeToby (1163751) | about 5 years ago | (#29595867)

If I were a science teacher, I think I would have a weekly contest "What's wrong with this?". I'd give all the kids a website, newspaper article, creationist newsletter (probably lose my job over that one but oh well), etc... and have them come up with a list of all the reasons that it is nonsense. Start with easy stuff (like the difference between EM and Ionizing radiation) and move to more challanging things later (like what a valid sample size is). We need to expose kids to the idea that not everything they read is gospel, to think critically about what they read and see and actually apply their education.

Re:Extra protection? (2, Insightful)

LordNimon (85072) | about 5 years ago | (#29596447)

Since you seem to know so much about it, why not create a web site that does just this? Even if school teachers can't do it, enterprising parents would probably like to use your site as additional education.

There's an idea for a startup - a company that creates additional homework for parents to give their children to make up for deficiencies in what their school teaches them.

Re:Extra protection? (1)

ArsonSmith (13997) | about 5 years ago | (#29596633)

Maybe you could have like a 3rd party wiki addon for browsers that would allow you to add comments to pages, independent of the page itself. You could then browse other peoples comments as well.

Re:Extra protection? (1)

Anonymous Coward | about 5 years ago | (#29596849)

I'm not sure anyone who quotes MSNBC is a good authority on what constitutes "nonsense".

Re:Extra protection? (1)

ArsonSmith (13997) | about 5 years ago | (#29596595)

"I wish I had a cross made of kryptonite. Because then I could kill Dracula and Supperman."

-Jack Handy

Re:Extra protection? (3, Funny)

AndrewNeo (979708) | about 5 years ago | (#29596689)

No, not Supperman! He brings me my dinner!

Re:Extra protection? (3, Funny)

PotatoFarmer (1250696) | about 5 years ago | (#29596831)

Ah yes, the elusive Supperman. I was very unhappy when Marvel finally decided to have him killed off by his arch-nemesis Bulimiax.

I still cherish my pristine copy of Supperman #103, in which he manages to incapacitate the entire Third Reich by making them fall asleep after a huge turkey dinner.

Re:Extra protection? (1, Funny)

Anonymous Coward | about 5 years ago | (#29595739)

You know that they tell you to use aluminum foil hats to INCREASE the effect of radio waves on your brain. The result is that you get paranoid enough to look in the wrong places for THEM.

Re:Extra protection? (4, Funny)

Abstrackt (609015) | about 5 years ago | (#29595841)

You might want to read this article [mit.edu] on the effectiveness of foil helmets. ;)

Re:Extra protection? (0)

Anonymous Coward | about 5 years ago | (#29596167)

foot thick lead helmets?

Finally!! (3, Funny)

Ludedude (948645) | about 5 years ago | (#29595161)

...a way to stop wearing this itchy tinfoil hat!

Re:Finally!! (1)

jennyfever (1646303) | about 5 years ago | (#29595511)

Exactly! I can just wallpaper my house with aluminum foil. Free mirrors AND I get to stop those freeloading hippies next door!

Re:Finally!! (1)

stokessd (89903) | about 5 years ago | (#29595529)

You need to make your hat out of sandpaper, the dark colored kind that is aluminum oxide. I'd recommend a fine grit unless you want the mellow exfoliating effect of 80 grit on your cranium.

Sheldon

Re:Finally!! (1)

Ludedude (948645) | about 5 years ago | (#29595781)

A good fashion tip. I hear aluminum oxide is the new black ;)

Re:Finally!! (1)

Gilmoure (18428) | about 5 years ago | (#29596769)

Paint your bald spot?

Resonance at other frequencies? (1)

acrobg (1175095) | about 5 years ago | (#29595185)

So I get that Aluminum Oxide paint is resonant at 2.4GHz. What about in the 900MHz band, or 1.2GHz band? What frequencies are not resonant in Aouminum Oxide paint?

Re:Resonance at other frequencies? (5, Informative)

John Hasler (414242) | about 5 years ago | (#29595335)

> What frequencies are not resonant in Aouminum Oxide paint?

The reporter is just yammering. He hasn't the foggiest idea what the word "resonant" means and knows less than nothing about radio. All we can glean from this is that someone has put out a press release about rf absorbant paint, something that has been around for decades.

Re:Resonance at other frequencies? (5, Informative)

Anonymous Coward | about 5 years ago | (#29595709)

All we can glean from this is that someone has put out a press release about rf absorbant paint, something that has been around for decades.

Using information in the article I was able to find the actual science paper [acs.org] . It turns out they are able to tune the resonate frequency of this paint. Very cool. However, the it doesn't go all the way down to 2.4 GHz. That's a pretty long wavelength for this process.

"By coating an entire room..." (3, Funny)

Anonymous Coward | about 5 years ago | (#29595195)

Wouldn't you have to paint over the windows?

Re:"By coating an entire room..." (0)

Anonymous Coward | about 5 years ago | (#29595541)

but I run linux.

Re:"By coating an entire room..." (2, Funny)

M8e (1008767) | about 5 years ago | (#29595575)

You could use a fine metal mesh instead of paint for the windows.

Re:"By coating an entire room..." (1)

sconeu (64226) | about 5 years ago | (#29595863)

Aluminum siding!

Re:"By coating an entire room..." (1)

SleepingWaterBear (1152169) | about 5 years ago | (#29596483)

Even with gaps in the coverage, blocking most of the radio waves should be enough to massively diminish the reception outside the room. Given the already limited range of most wifi transmitters, a few gaps in the paint for windows shouldn't be enough to allow any practical use of the wifi signal from outside.

Now, if you're putting the paint up for security reasons the windows might constitute a real risk, but trying to restrict the range of your wifi transmissions is probably not the best approach to security anyway.

Re:"By coating an entire room..." (1)

rossdee (243626) | about 5 years ago | (#29596783)

Obvious answer: Transparent aluminum. Its a lot stronger than glass, so you have less to worry about with storms.

Hey, it's good enough for the office... (4, Funny)

d474 (695126) | about 5 years ago | (#29595197)

I dipped my head in this aluminum oxide paint, and it keeps all their signals out. Granted, I look somewhat like a cyborg now, but this stuff should work just fine for an office trying to keep their signals in.

Re:Hey, it's good enough for the office... (2, Informative)

Anonymous Monkey (795756) | about 5 years ago | (#29595813)

Looking like a cyborg is good, because the other cyborgs won't try to assimilate you. However, it is important to have a radio transmitter with you everyplace so that you are broadcasting some sort of radio signal at all times. Now, at home, it is still better to line your walls with aluminum foil, but you need to do so INSIDE the walls, behind the drywall, because you don't want the government drones seeing it. You should line your attic as well, but not your basement, because The Worms are attracted to foil. In your basement you should use lots and lots of crushed cans. Sprite cans works best.

Re:Hey, it's good enough for the office... (0)

Anonymous Coward | about 5 years ago | (#29596553)

Thank god, I did this when I built my house 14 years ago!

Note: AlFeO *not* Al2O3 (5, Informative)

Anonymous Coward | about 5 years ago | (#29595205)

Note, the material concerned is Aluminium IRON oxide. Big difference. Aluminium oxide is a good dielectric and would be bugger all use for RF shielding. Oh and the article is a wierd too: it talks about 100GHz shielding where WiFi bands are ~ 2.5GHz.

Re:Note: AlFeO *not* Al2O3 (2, Informative)

fuzzyfuzzyfungus (1223518) | about 5 years ago | (#29595579)

Unless this stuff is very much unlike a certain other [wikipedia.org] aluminum iron oxide composition, there might be a certain other big difference...

Re:Note: AlFeO *not* Al2O3 (1)

BrokenHalo (565198) | about 5 years ago | (#29596701)

Don't knock it - self-illuminating houses (even if only for milliseconds) are the in thing in the new energy-concious world. ;-)

Re:Note: AlFeO *not* Al2O3 (1)

mrstrano (1381875) | about 5 years ago | (#29595987)

The real question is, why?

There is cryptography for that. Now, apart from the unfortunate and deprecated WEP protocol, there are some really secure alternatives out there, like WPA2.
Certainly more secure than a leaky insulation.
It would be like sending a secure mail over in a physical vault, rather than using PGP or GPG. Who would do that?

Rebound? (1)

Rhaban (987410) | about 5 years ago | (#29595245)

So if this paint resonate with wifi signal frequencies, does the signal rebound on it, increasing risks of getting cancer and/or global warming in your own home?

But Why? (1)

quatin (1589389) | about 5 years ago | (#29595279)

Lock your WiFi? I prefer to unlock my WiFi. Stick it to the cable companies!

Re:But Why? (1)

hodet (620484) | about 5 years ago | (#29595885)

That way when I hit my 30gig cap the whole community can enjoy dialup speeds. Sweet, that'll show'em.

Does not resonate with me (5, Insightful)

Ancient_Hacker (751168) | about 5 years ago | (#29595283)

Dunno where they got the crap about "resonates".

The paint might act as an electrostatic shield, or as a lossy dielectric, both effects that will attenuate RF signals.

  But resonate, no.

Re:Does not resonate with me (5, Interesting)

_avs_007 (459738) | about 5 years ago | (#29595435)

Seriously... I work with a WiFi lab at work... I have a Faraday Cage in our lab... One of the techs forgot to install an optical isolator on the network cables, so for a few days the ethernet cables went right into the cage... Well, first day I went to use it, I locked myself in the cage, and was surprised that my cellphone started ringing... Without the optical isolators on the network cable, the RF signals were able to find there way into the faraday cage through the ethernet cables....

with that being said, I highly doubt that simply painting your walls will keep RF signals at bay... Even when the grounding wire was simply loose on the door to the faraday cage, RF signals would leak in...

Re:Does not resonate with me (5, Funny)

quatin (1589389) | about 5 years ago | (#29595561)

So you went inside a Faraday Cage with an unprotected ethernet cable and managed to get cell phone reception. I on the other hand, can't get cell phone reception if I stand too close to my filing cabinet. I either need to switch to your provider or you need to come do your WiFi experiments next to my filing cabinet.

Re:Does not resonate with me (1)

afxgrin (208686) | about 5 years ago | (#29595811)

I take it you were using fiber optic cables into the Faraday Cage, so that you weren't adding electrical noise inside?

Otherwise it sounds like you're trying to put a device for protecting optical transmitting equipment from return losses on an ethernet cable.

Re:Does not resonate with me (1)

Rick17JJ (744063) | about 5 years ago | (#29596085)

What are they planning to do about the keeping the signals from getting through the windows? Are they going to install screens on the windows which will block those frequencies? Are they going to paint the curtains? Are they going to install interior or exterior shutters, and then paint them too with the anti-WiFi paint which contains aluminium-iron oxide.

I am not an expert, but it seems to me that they would need careful attention to details such as those, to adequately block the signals. For example, I know someone who was recently able to use a campground's free WiFi from withing his old aluminum Airstream trailer. My guess was that the signal was coming in through the window, or possibly through the floor.

However, even if the blocking of signals is not perfect, the anti-WiFi paint might be useful, if that is only one of several other protection measures that are being used. That would especially be true if someone has is parked out front and is using a directional yagi or other type of antenna, hidden in something like a Pringles can. For instance, they probably still should use WPA or WPA2 with a sufficiently long and random password that also includes numbers and punctuation. It would be best to also change the well know default password on the wireless.

Re:Does not resonate with me (1)

Cyner (267154) | about 5 years ago | (#29596195)

There's only 1 way to complete protect a wireless network: Turn it off.

Everything else is just a layer to help protect it, paint addatives included.

Re:Does not resonate with me (1)

Skuld-Chan (302449) | about 5 years ago | (#29596259)

Conversely my brother in law works at a wireless lab where they have a copper clad cage, and when he closed the door my cellphone lost its network signal within a few seconds.

Strangely enough the government transmissions didn't stop infiltrating my brain :(.

Re:Does not resonate with me (2, Informative)

elashish14 (1302231) | about 5 years ago | (#29595859)

Ionic materials can be polarized to interact with electromagnetic waves to block signal transmission. They have a number of absorptive mechanisms. The highest frequency absorption mechanism is where electrons around the nucleus resonate, roughly at 10^17 Hz. Then there's atomic vibrations where the nuclei themselves vibrate (10^14 Hz I think). Not sure what they are for the material used in particular though, but ionic materials can resonate. It doesn't seem that they're in the range used for this application

Re:Does not resonate with me (1)

MozeeToby (1163751) | about 5 years ago | (#29595989)

This article is full of nonsense, it's not even worth the read. For example...

Movie pictures are beamed on the screen by the projector at the back of the cinema. But in the future, you could use a data link that works with millimetre waves.

What. The. Fuck. is that supposed to mean?

Re:Does not resonate with me (1)

zippthorne (748122) | about 5 years ago | (#29596843)

Everyone will still go to the movie theater, but they'll watch the film on their iPhones. They will be confused when the "turn off your annoying cellphones (psst: you can buy annoying cell phones from AT&T)" message comes on, though.

Re:Does not resonate with me (0)

Anonymous Coward | about 5 years ago | (#29596495)

What they are probably talking about when they say resonate is that the individual molecules resonate, just like water molecules in a microwave oven. What they are creating is a lossy paint. I have my doubts that it is really resonant over the entire range (DC-100GHz) though I am fairly sure that it would block all signals in the 380-750nm range.

Why not share wi-fi? (4, Interesting)

presidenteloco (659168) | about 5 years ago | (#29595311)

We do know the world would be a better place if everyone shared their wi-fi securely using
a technology like FON, don't we. (No I'm not associated with the company. Just recognize a
great concept when I see one.)

I'm seriously tired of how, particularly in the US, sharing wi-fi gets implanted in peoples'
brains as a criminal, borderline terrorist activity, with terms such as
"theft of tele-communication resources" and similar Orwellian mindf**k terms.

Re:Why not share wi-fi? (4, Funny)

RabidMoose (746680) | about 5 years ago | (#29595507)

Admit it. You're just bitter that your neighbor finally turned on WPA2, and now you have to go to the library to read Slashdot.

Re:Why not share wi-fi? (1)

Kylock (608369) | about 5 years ago | (#29595585)

There are plenty of security concerns with an unencrypted network.>While FON looks like it may be interesting to some people, I need all my bandwidth for my porn.

On a more serious note, many providers in the US will cancel or severely cripple your service if you use so much bandwidth in a month or other predefined timespan. There are other factors to consider.

Re:Why not share wi-fi? (1)

icebraining (1313345) | about 5 years ago | (#29595795)

FON creates two different networks, one for sharing and one for private use, and AFAIK you can limit the bandwidth and throughput used by the public one.

Re:Why not share wi-fi? (2, Interesting)

cheros (223479) | about 5 years ago | (#29596591)

Correct. And you can decide if you want to share free of get a kickback. If you share for free you are also entitled to access all other FON nodes in the world, if you share for a revenue share you have to pay. Pretty fair model IMHO.

However, I'm unhappy with a node on my personal network where someone can change code on the fly, which is why I took it offline a while back.

Re:Why not share wi-fi? (0)

Anonymous Coward | about 5 years ago | (#29596547)

Of course there's nothing wrong with sharing a wireless network, when everyone agrees to it. I can't imagine anyone having a problem with that. But I don't think this story is really about the home user. I'd assume this technique would be more popular with a business storing highly sensitive data. Of course, there's an even better solution (ethernet), but that would mean the executives would have to give up their precious wireless.

Is it safe ? (1, Interesting)

CharlyFoxtrot (1607527) | about 5 years ago | (#29595375)

We all know about the hazards of lead based paints, so is this safe ? I'm assuming the plastic lining in aluminum cans is there for a reason. Perhaps adding panelling containing a solid aluminum oxide mesh of some sort would be better.

Re:Is it safe ? (1)

Fujisawa Sensei (207127) | about 5 years ago | (#29596687)

We all know about the hazards of lead based paints, so is this safe ? I'm assuming the plastic lining in aluminum cans is there for a reason. Perhaps adding panelling containing a solid aluminum oxide mesh of some sort would be better.

An easy solution would be to stop eating paint.

by misspelling aluminium? (-1, Troll)

Anonymous Coward | about 5 years ago | (#29595549)

apparently

Re:by misspelling aluminium? (0)

Anonymous Coward | about 5 years ago | (#29596551)

From the surprisingly well-written/sourced Wikipedia article:

Present-day spelling

Most countries spell aluminium with an i before -um. In the United States, the spelling aluminium is largely unknown, and the spelling aluminum predominates. The Canadian Oxford Dictionary prefers aluminum, whereas the Australian Macquarie Dictionary prefers aluminium.

The International Union of Pure and Applied Chemistry (IUPAC) adopted aluminium as the standard international name for the element in 1990, but three years later recognized aluminum as an acceptable variant. Hence their periodic table includes both. IUPAC officially prefers the use of aluminium in its internal publications, although several IUPAC publications use the spelling aluminum.

Translation: Quit being a douchebag.

What is so hard about using WPA2? (5, Insightful)

Anonymous Coward | about 5 years ago | (#29595621)

You select WPA2-PSK in your router's config, press "generate key", make a note of the generated key, connect your laptop to the encrypted WLAN, enter the key, done. No beacon disabling, radio frequency shielding, MAC filtering, DHCP disabling or other nonsense necessary. It's like people are trying to test every option but the right one.

Re:What is so hard about using WPA2? (2, Interesting)

ElectricTurtle (1171201) | about 5 years ago | (#29596345)

Encryption can be broken with less effort than a physical wall. It's also fundamentally naive to propose that one layer of security of any kind is the silver bullet that makes all other layers unnecessary. I use encryption and MAC address lists together because it means that if somebody wants to get in they have to do two things instead of just one. Can people still get in? Duh. Everybody should already know that wireless network security is about making a harder target than the one down the street.

Re:What is so hard about using WPA2? (1)

Hal_Porter (817932) | about 5 years ago | (#29596855)

What about HARM missiles aimed at enemy WiFi transmitters? How do you feel about those as a means to prevent unauthorized access to your network?

It's not WiFi its see through walls mm waves (1)

mbone (558574) | about 5 years ago | (#29595723)

It's not WiFi they are protecting against - its "see through walls" mm waves that this will be especially effective against.

From the article :

"I'm working on a material that can absorb a larger range of frequencies. We are capable of making a paint that can absorb over 200 gigahertz."

This will stop Through-the-Wall Surveillance Technology cold. [nowpublic.com]

Since 100 GHz is a 3 mm wave, and 200 GHz a 1.5 mm wave, they much have fairly small (100 micron) aluminum oxide particles in the paint.

Now, the paint will also stop any lower frequencies (longer wavelengths). However, these waves will go through any open holes in the paint that are much larger than a quarter of a wavelength or so - such as doors and windows. (Cell phones typically have wavelengths of about a meter to 10 cm - these low frequencies will also refract around household objects, while mm waves are much more line of sight.) So, I predict that in many cases the cell phone will work, while the "see through wall" technology will not. Of course, you'll have to make sure not to put what you are trying to hide in front of a window - or to get a very fine-meshed window screen.

Could this also enhance the signal? (1)

elashish14 (1302231) | about 5 years ago | (#29595753)

You should theoretically have enhanced signal quality if you're keeping it within the walls. All that radiated power that would have gone outside will remain inside, so there must be some sort of net increase in power radiated to your computer antenna.

Unless. . . (1)

JSBiff (87824) | about 5 years ago | (#29596819)

Unless this compound does something like absorbing the RF, and in the process, attain a slightly higher temperature/thermal energy state. If that's the case, it would be like shining your flashlight on a black surface (most 'black' paint still reflects some light, but I hope you get the idea).

Floors? (1)

Tubal-Cain (1289912) | about 5 years ago | (#29595815)

...most pre-finished wood flooring uses aluminum oxide as a protective coating.

So... I can stop worrying about the gophers leeching my WiFi?

Ahah! (1)

rickb928 (945187) | about 5 years ago | (#29595825)

"You or your neighbors may be unwittingly using this already, as most pre-finished wood flooring uses aluminum oxide as a protective coating."

Finally, I can get rid of that kid in the basement!

BAHAHAHAHAHA! PWNAGE!

Usefull in heavily saturationed WIFI areas (2, Interesting)

ACMENEWSLLC (940904) | about 5 years ago | (#29595965)

Where I am there is some WIFI (hidden or not) on every channel. There are large broadcast towers about half a mile from me which have various Internet over 802.11B from service providers.

My WIFI in my home has a hard time with all this. This paint would be a good way for me to improve my in home signal. A lot of my equipment doesn't support the new 5Ghz of 802.11N, so while I have 802.11N APs they do not help much.

limit my wifi? pah (2, Interesting)

jackflap (715225) | about 5 years ago | (#29595993)

The number of times I've "borrowed" wi-fi from a neighbour, I felt obliged to leave mine open for everyone to use.

I did however install the Tomato firmware on my router, and use it's brilliant QoS to limit all machines but my own to 56k connections :)

Until someone opens a window or door (1)

loftwyr (36717) | about 5 years ago | (#29596011)

this sounds lovely. We just need to paint all surfaces and make sure all doors and windows are painted over and sealed. Nobody gets in or out and then we're all safe from RF leakage.

Of course, then everyone in the building dies and there's no more need for the security...

Re:Until someone opens a window or door (0)

Anonymous Coward | about 5 years ago | (#29596251)

Just have a two-door "airlock" system.

Idiot.

flamable much? (0)

Anonymous Coward | about 5 years ago | (#29596119)

I could just misunderstand all of this, but painting your walls with something so similar to thermite (http://en.wikipedia.org/wiki/Thermite) seems like a bad idea.
Anybody remember what caused the Hindenburg disaster? People should watch mythbusters more.

Re:flamable much? (1)

networkBoy (774728) | about 5 years ago | (#29596621)

this material is an Oxide. Thus it is already "burnt".

Great (0)

geekoid (135745) | about 5 years ago | (#29596133)

Now please paint movie theaters with it.

oh, and for the alarmist:
The movie theater can put a sign outside indicating that there signals will be blocked.

I know this isn't cell blocking, but a lot of text Traffic is moving to wi-fi.

Won't someone please ... (1)

PPH (736903) | about 5 years ago | (#29596269)

.... paint the BBC's broadcast antennas with this stuff?

The BBC reports...

My basement does a good job (2, Interesting)

Jim Hall (2985) | about 5 years ago | (#29596331)

I happen to live in Minnesota, where most homes have basements. Our Comcast cable enters the house through the basement, so I figured it was a convenient place to hook up the WiFi access point. The WAP is sitting on the bottom shelf of a bookshelf I have there.

The net effect is that I have great WiFi signal throughout the house. I have a wood frame house, and WiFi signal is not retarded by normal wood construction. However, I get almost no signal as soon as I step out the back door onto the porch. A few feet away from the house, I can't pick up the signal at all. I've also tested it from the street, and it's like my WAP isn't even there. No, I'm not using any special paints or "Faraday cage" wallpaper.

That's because basements are constructed from cement blocks, which do a pretty good job of retarding WiFi signal. Not to mention my basement is 6-7 feet underground (there are windows at almost ceiling height) and all that dirt also helps block the signal. I figure I'm pretty safe from snooping. Sometimes it helps to just be incrementally harder to get to than the next guy. If you're a wardriver who's interested in free WiFi, my neighbor two doors down is an easier target (his WAP is on the second floor of his house, so he's essentially broadcasting to the whole neighborhood.) Or I suppose you could drive down a block and a half to the coffee shop who runs a completely open WAP.

* And yes, I do use good WAP security, with encryption, long passphrase, MAC filtering, only wired connections are allowed to connect to the admin screen.

Flawless Solution or Not (0)

Anonymous Coward | about 5 years ago | (#29596557)

"You or your neighbors may be unwittingly using this already, as most pre-finished wood flooring uses aluminum oxide as a protective coating."

This is to stop the CHUD from getting free wifi.

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