Can Faraday Cages Tame Wi-Fi?

mrraven writes "An article at TechWorld discusses the increased need for wireless network security. One possible solution to this problem is the use of building-wide Faraday cages to block the wireless signal from 'leaking'." From the article: "Small installations of RF shielding don't have to be expensive, and the basic concept of a Faraday cage can be extended to all kinds of small everyday objects. Leather wallets sandwiched with a conductive RF-shielding layer can prevent RFID scanners from reading personal information implanted in everything from RFID-enabled access control cards to some credit cards; they're widely available for as little as US$15. For those favoring a more DIY route, several Web sites have information on how to make an RFID-blocking wallet with duct tape and aluminum foil."

Comments

The truth may be out there...

[Cygfrydd]

So this is essentially a giant tinfoil hat for your office? Will it stop the voices as well?

Re:The truth may be out there...

[arivanov]

It does not need to be a tin hat.

Our office has IR tempered glass (which is quite common in "all-glass" buildings nowdays.

Stops WiFi dead in its tracks. The signal drops by 20+db when going outside the building to the point where you can no longer home in with a normal receiver. Granted, this will not help against a professional attacker, but it is more then enough against random wardriving k1dd10tz.

So if you have to chose between two buildings which are all-glass and glass windows + wall for a new office the all-glass is better as far as WiFi is concerned. Wardrivers aside, allocating channels without worrying about neighbours is quite a nice thing to have.

UK defense system

[legoburner]

BAE in the UK have made a wallpaper to do just this. No word on if it is available to consumers though I bet there is a market in the paranoid EM fearing folk that live near 'evil' cell phone masts.

Faraday Cages will work

[jmauro]

Only if you don't want cell phone coverage or look out side. I work in a building that is EM sheilded using a Faraday cage. It was designed to test new radios so you didn't want outside signals coming in to mess up the test. Needless to say a all-metal no windowless office sucks. You have to go out side to make a cell call and when the AC breaks you're screwed because the place turns into an oven with no windows to open. It's a nice idea, but I doubt most wouldn't like to work in such a place 24-7. I sure don't.

Re:Faraday Cages will work

[JesseL]

A wire screen tends to block EM with a wavlength greater than about twice the size of the holes in the mesh. Since the visible spectrum is in the few hundred nanometer range, and most RF communication happens at wavelengths over 5 centimeters, a screen is a very viable option.

Leaky

[QuantumFTL]

I'm sure this will help minimize effects of leakage, but no building can have a "perfect" faraday cage on standard wifi frequencies - the wavelengths are far smaller than the openings required for humans to enter and exit the building.

Once again, it's probably better to focus on good encryption, though this is hardly much help to defeat certain on-site DOS attacks. Then again, that's what your security force is for :)

Oh, come on

[happyemoticon]

The best wireless security solution is just to not use wireless. Yes, it's sexy. Yes, I know it can be a pain when there's a split in an ethernet cable that's in the rafters. Yes, I like to be able to use this laptop on the couch because it helps my creative energies get flowing. But seriously, if I were at all concerned about security, I'd just stick at CAT5E into the side and be done with it. Big wireless deployments are things for college students and people who like cafes. If I were running a business, I wouldn't throw money at a wireless project to begin with, let alone build an elaborate jamming/shielding system to correct problems which could've been avoided by not doing anything in the first place.

Thank god we got rid of wires

[Anonymous Coward]

So we can replace the wires from each user to a building-wide mesh of wires.

Re:What about windows?

[zlogic]

I totally agree with you. Until Windows is replaced with something more secure, the network can be easily accessible from outside.
Oh wait...

Why does it have to be a physical?

[DoubleRing]

There are so many ways of securing a wireless network without the messy business of placing a mesh wire around the building. The university in the town I live in has a campus wide wireless network. They then use a vpn system (cisco, I believe) to regulate access. Simply, anyone can connect to the wireless network, but you are given no access unless you connect to the university's vpn. Then from there, depending on that account's permissions, you can access the Internet and the university network permissions. I think this system is probably the best ideas because very little additional hardware is required, each account has a separate username/password combination (if the password is compromised, you only are dealing with a single user), and has the added bonus of being able to access the university resources from home. Plus, it works flawlessly with Linux.