Photon detectors are extremely accurate, able to detect single photons passing between two points, but they aren't perfect and sometimes they read false positives. Bash's technique makes use of that flaw using pulse position modulation — and it's not much more complicated than Morse code.Basically you hide the message in transmission noise. It works on fiberoptic, it works better on cell phone frequencies in the EM band, where there's lots of noise. The article goes on to say that the message size in only hundreds of bits per second, but that's more than big enough to do an awful lot of things given the processing and storage capability we have at our disposal these days. Like control a semi-autonomous robot, for example. Can't jam it if you can't see it.
Take a unit of time, like a second, and chop it up into smaller parts that vary in size, one-fourth, one-eighth, etc. Then assign each band a corresponding symbol. There's your code. You can transfer a photon-based message over a fiber-optic capable that corresponds to the code and — so long as the message sender and the receiver of the message both have the key to the code — then each can read the message.
Tuesday, May 13, 2014
Quantum encryption and invisible messages.
Behold, there IS a way to escape the All Seeing Eye of Sauron. It is ingenious!It will be interesting to see how long it takes the USA to pass laws banning the use of tools like this.