You might be using something like RedPhone by Moxie Marlinspike or PrivateGSM in a corporate network to communicate securely. Even with these solutions and state-of-the-art encryption are you really secure and free from someone being able to surveil you while you are on the phone?
What a Laser Microphone Is
A laser microphone is a microphone that uses a laser beam to detect sound vibrations in a distant object. Laser microphones are not very common but are sometimes used by law enforcement and other types of authorities. Laser microphones are generally pretty simple to build and use. You can build a laser microphone at your house if you have the desire to. You could also buy a laser microphone online or in some cases at your local stores.
How a Laser Microphone Works
How a laser microphone works is pretty simple. You usually have a laser beam directed into a room through a window, the laser beam either goes into the room and reflects off an object like a mirror or off of the window itself. Once the laser beam has bounced off the object it returns to the receiver, which then converts the beam into an audio signal. This concept a lot of times does not work as well as you would think it would. There are a lot of factors involved in the process like what is between the receiver and the source (where the laser is being bounced off of). If there is anything in between the laser and the source, your end result might not be very good. Altitude can be another factor to consider. If you or the source is at a different altitude then this might not work very well.
What Can We Do
There are several different ways that you can defend against this type of surveillance. One method would be to block out any windows in a room where you would like to have a private conversation, or make sure the room does not have any windows at all. Another defense, if you need to have windows in the room, would be to have rippled glass instead of regular clear glass. Rippled glass is a very poor surface for a laser microphone. Therefore it does not allow the laser or sound waves to pass through the glass very easily.
Thank you all for taking the time to read this post and as always God bless!