Re: Snake Oil: Stealth wallpaper keeps company secrets safe

From: John Larkin (jjlarkin_at_highSNIPlandTHIStechPLEASEnology.com)
Date: 08/16/04 

Date: Mon, 16 Aug 2004 13:08:21 -0700

On Mon, 16 Aug 2004 08:54:13 -0700, Guy Macon
<http://www.guymacon.com> wrote:

>
>
>(Snake Oil, anyone?)
>
>| Stealth wallpaper keeps company secrets safe
>|
>| August 04
>| New Scientist Magazine
>| http://www.newscientist.com/news/print.jsp?id=ns99996240
>|
>| A type of wallpaper that prevents Wi-Fi signals escaping
>| from a building without blocking mobile phone signals has
>| been developed by a British defence contractor. The
>| technology is designed to stop outsiders gaining access to a
>| secure network by using Wi-Fi networks casually set up by
>| workers at the office.
>|
>| It is the work of moments for an employee to connect a
>| paperback-sized Wi-Fi base station to a company network.
>| That person can then wander around the office with their
>| laptop while remaining wirelessly connected to the internet.
>|
>| But it is also the work of moments then for an outsider to
>| breach that company's computer security using the Wi-Fi
>| connection. Unless the Wi-Fi base station is protected by
>| security measures that most amateur users would not bother
>| to set up, it gives anyone up to 100 metres away the chance
>| to bypass the corporate firewall and wirelessly hack
>| straight into the network.
>|
>| Until now, the only way to ensure people are not illicitly
>| gaining access to company secrets has been to turn offices
>| into a signal-proof "Faraday cage", by lining the walls with
>| aluminium foil, and using glass that absorbs radio waves in
>| the windows. This ensures all electromagnetic emissions are
>| absorbed, but it also means that no one can use a cellphone
>| in the building.
>|
>| So the UK's telecoms regulator, Ofcom, has paid BAE Systems,
>| formerly British Aerospace, to come up with an answer for
>| firms who are becoming increasingly worried about the
>| threat. BAE Systems has based its solution on the secret
>| "stealth" technology that it uses to hide military radars.
>| The covering, called Frequency Selective Surface (FSS)
>| sheeting, is used to shroud radar antennas on warships or
>| aircraft.
>|
>|
>| Copper coated
>|
>|
>| Solid metal antennas normally give a very strong reflection
>| to enemy radar scanners. To hide them, FSS sheeting can be
>| electrically set to allow through only the precise frequency
>| the antenna wants to transmit and receive, while absorbing
>| all other frequencies including those of the incoming radar.
>|
>| BAE's anti-Wi-Fi wallpaper is made from a
>| 0.1-millimetre-thick *** of kapton, the same plastic used
>| to make flexible printed circuit boards in lightweight
>| portable gadgets like camcorders. The kapton is coated on
>| each side with a thin film of copper.
>|
>| On one side most of the copper is removed, leaving a grid of
>| copper crosses. On the other side, matching crosses, turned
>| through 45 degrees, are etched away ¬- leaving a film of
>| copper with a grid of cross-shaped holes. BAE says that by
>| carefully changing the size of the crosses and their
>| spacing, the *** can pass precisely defined frequencies,
>| while blocking all others.
>|
>| But they are not revealing how the military technology works
>| except to say it is a little like an optical diffraction
>| grating creating interference to destroy certain light
>| frequencies. "We have developed formulae for this, which we
>| aren't going to give away," says project leader Kevin
>| Mitchell.
>|
>|
>| On or off
>|
>|
>| Ofcom engineers have confirmed to New Scientist that the
>| wallpaper can block Wi-Fi at 2.4, 5 and 6 gigahertz, while
>| letting through GSM and 3G cellphone signals, plus emergency
>| service calls.
>|
>| Better still, the filtering can be switched on or off if
>| diodes are connected between the copper crosses. When a
>| current is fed through the diodes, all frequencies are
>| blocked. Switching them off "opens" the panel to let mobile
>| and emergency signals through.
>|
>| The wall covering can be mass produced at relatively low
>| cost. A square metre will cost about £500: peanuts to big
>| business.
>|
>| BAE is now working on a transparent, ultra-thin version for
>| windows. William Webb, Ofcom's R&D chief, says: "With this
>| new technology, signals can be shared securely and go where
>| they need to go, and no further."
>|
>|
>| Barry Fox

I just finished reading "Skunk Works" by Ben Rich, who led development
of the stealth fighter. It has a radar cross-section about the same as
a 0.5" diameter ball bearing. To sell it to the brass, they went to
the Pentagon and rolled ball bearings on peoples' desks, and told them
they could have a jet plane with the same radar reflectivity.

John

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