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."

What about windows?

[jdhutchins]

While adding a thin mesh around the building might not be hard to do at construction time, it seems the author has ignored windows. Most larger commercial buildings have large windows, which would need to be covered in a mesh in order to make the whole building a farady cage. This would obviously seriously impact the building's appearance, and I doubt would ever become practical. It's not that difficult to set up a WPA2 or VPN setup if you're concerned about keeping wifi secure.

Cell Phones

[Soul-Burn666]

After succeeding in preventing the wi-fi signal from "leaking", you are surprised your cellphone stopped working.

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.

Re:Faraday Cages will work

[Cthefuture]

A Faraday cage does not require a solid sheet of metal. It can be a wire mesh.

There is stopping you from having windows. All you need is a metal screen either on the inside or outside. This also allows you to open the windows for some air. There is also EM blocking glass that has a very thin mesh overlaid or embedded which is basically invisible (similar to some touch screens).

The only times I have been in EM protected areas with no windows is when there was confidential work being done and they didn't want anything visible from the outside.

Re:Faraday Cages will work

[mad_minstrel]

Most wouldn't want to work 24/7 anywhere at all.

Re:What about windows?

[IdahoEv]

Moreover, if it was done correctly it would completely prevent cell phones and blackberries from working. I doubt that would fly in today's business environment.

Re:Leaky

[ip_vjl]

Visible light is just another part of the electromagnetic spectrum, but you can easily create a human doorway to another room that keeps light out, even when in use.

The two types I've seen in photo darkrooms are:
1) The light baffle. The entry doorway is just an 'S-shaped' hallway that requires you to turn a couple of times to pass through. There doesn't need to be any door to open/close, but as long as it isn't lined with a material reflective to what you are trying to keep out, you're ok. Look under your sink at the drain catch for the idea. The nice thing about this style door (for darkrooms, etc) is that you never need to worry about having to mess with any door mechanism in the dark. It's completely open to wander in and out (for people, air circulation, etc.)

2) The revolving door. There is never an open conduit from the outside to the inside at any time. The opening closes off from the external environment completely before reaching the point where it opens to the internal environment.

Re:What about windows?

[DeadChobi]

Not to point out the obvious or anything, but it's also possible to set up an antenna on the inside which will repeat a signal to an antenna on the outside of a building. They do this in sports stadiums and various other places because of the lack of reception. The antenna doesn't repeat all frequencies, meaning that you can set it to repeat your crackberry's signal but not your ultra-secure Wifi signal.

Re:I doubt it... basic physics

[jpardey]

It isn't that hard to stop that kind of thing, actually. Best kind of wire for it: standard ethernet cables. Buy a few switches off of ebay just as everyone else tries going wireless.