By Darrell Smith
Open up your Wi-Fi enabled laptop outside and right away in your network management pane you will see a list of wireless systems. Most, if not all of them are broadcasting from inside a building. Office buildings may have hundreds of signals spilling out the walls and windows. Add to this people using mobile phones, electronic payment systems, and security signals and you have a treasure trove of information literally in the air.
That’s just what some savvy cyber thieves knew when in 2007 they stole the credit card information of over 45 million customers of TJX Cos., parent company of Marshalls, T.J. Maxx, HomeGoods, and other stores. The information was taken out of thin air.
Investigators believe hackers sitting outside a Marshalls used a telescope-shaped antenna to grab information leaking out from windows from the store’s wireless data system communicating between handheld price checking devices, cash registers, and the store’s computers.
Many retailers and office complexes try to make their environments more appealing by letting in more light, but in doing so they’re also allow more information to flow through the glass.
Government officials have known about the problem of eavesdropping on data, phone conversations, or even plain talk between people in an office for decades. It is estimated that more than 200 buildings within federal agencies, including the departments of Defense, Treasury, and State use a special type of window film to combat this issue.
These films are one of the solutions developed to prevent information from falling into the wrong hands. These window films, which are among the most sophisticated products made by the window film industry, were developed for sensitive federal government facilities to prevent secret data from being copied through the windows of buildings. These types of products can help to confine RF (radio frequency), IR (infrared), and optical bandwidth transmissions across and from wireless networks, laptops, cell phones, computer monitors, laser microphones, and infrared communication systems within a protected space.
But it’s not just the wireless data that can present a tempting target. Private conversations between people or on a phone can also be eavesdropped or intercepted using readily available receivers. Laser microphones allow the user to pick up voice data through a window.
The signal and voice blocking window films can be visibly clear so it’s not obvious they are in place.
Serious wireless product developers have been shielding rooms for years to provide a “quiet” chamber for testing wireless products in the absence of external RF signals. Combined with the use of special RF shielding paint and other steps, window film offers an attractive way for protecting larger rooms and even buildings.
With this type of shielding, a building gains a “protective skin” that offers another layer of security on top of existing security mechanisms, such as encryption and authentication.
In addition, window film provides benefits such as reducing UV exposure inside by as much as 99%; keeping glass together when it has been impacted by an object or a blast wave from an explosion; increasing energy savings, especially for buildings that require cooling much of the year; and reducing glare so the interior environment is generally more comfortable and occupants can take advantage of natural light.
Smith is executive director of the International Window Film Association.