It seems that wireless devices are taking over our lives. Starting with wireless internet most other computing devices are now also wireless. We have wireless keyboards, wireless mice, wireless telephones, wireless headphones and wireless CCTV. Companies that sell these devices are fairly quick to point out how convenient it is to use the wireless device and how long the wireless range is, but very few of them actually publish information about if the wireless communication on the device is secure.
In very loose terms, wireless communication happens through air. The data to be sent is usually modulated at a popular radio frequency of 2.4GHz for mid range transmission and then released into the air. The receiver receives the radio signal and demodulates it and reads back the data. Some devices like remote controls and infra-red headphones modulate light rather than radio signals making the wireless communication line-of-sight only, as any solid object blocking the modulated light will interrupt communication.
Now unless both the transmitter and receiver have in-built security features to prevent it, the transmitted signal can be intercepted by any similar receiver within range, not just the intended one. In other words it is far easier to tap into wireless communication than it is to tap into a wired one, since the signal is freely available in air.
So how can devices make their transmission secure? Well they need to setup a secret key between the transmitter and the intended receiver. This is usually done once. The transmitter than scrambles (encrypts) the data using the key before transmission and the receiver descrambles (decrypts) it. Another receiver in-range can still demodulate the signal but will receive scrambled data which won’t make much sense without the pre-shared key.
Most wireless internet routers come with advanced WPA based security which means communication signals are encrypted. However many smaller devices like keyboards do not. This is a major security risk for computer users as passwords and credit card information typed on the keyboard can be intercepted. Some models like the Logitech EX110 have clever security features which are only enabled when you install the driver software on disk, but most users simply plug the device in and start using it without installing the specific driver software. Wireless video senders and wireless CCTV cameras are worst offenders many with no security features to encrypt the transmitted signal. Wireless video scanners can easily intercept the signal and suddenly your home is exposed to electronic peeping toms without your knowledge. The same is true for FM transmitters, any one with a FM radio in range can listen to your music. Many of us may not mind someone listening to our music, but it’s a completely different story when using a cordless telephone or children's walkie-talkie. Tapping into your phone line and listening to your communication is suddenly easily possible using a radio scanner.
What can you do? Well first of all check with the manufacturer if the device you intend to buy has secure wireless communication. Having more channels does not add to security of a radio device. Radio devices using frequency hopping1 are more difficult to tap into and cordless phones with DSST or DECT technology are more secure. Bluetooth wireless devices that support pairing, though more expensive, are more secure, as security features have to be built-in for them to work correctly with Bluetooth protocols. If it is not secure, you are better off getting a wired device instead. If you don’t have a choice, then try to get a device with a transmission range close to what you really need or go for a line-of-sight type receiver. Also switch off wireless transmitters when you are not using them.