Researchers at the University of Massachusetts at Amherst and Raytheon BBN Technologies have created a way to make your email correspondence so secure (PDF), that even the NSA would have a hard time getting to it.
It’s called digital steganography, which means hiding messages within other messages.
Messages are sent through fibre-optic cables and use light to communicate. If someone is monitoring the photons passing through the cables, then they can see when communication is being sent. Although the photon detectors are accurate, they’re not perfect: Sometimes they read false positives. And the researchers have figured out a way to exploit that flaw, and have created something that resembles Morse code.
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 fibre-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.
The messages always look like background noise to someone who’s keeping an eye on your correspondence. This type of secret code messaging could also work with text messages through cell towers.
The trick, though, is that the person you’re corresponding with also needs to be privy to the code, and you need to exchange that information. And the way to do that without being detected, is to share it in an encrypted email that destroys itself when an outsider reads it, Defence One says.
This is called quantum encryption:
Quantum encryption offers the possibility of a message so secure that any attempt to read it without authorization will destroy it, not because of some programmer’s whim but because of the way subatomic particles operate.
So using these two techniques, someone could send a perfectly secure message. A third party could see that something was sent, but wouldn’t know the content of the message.
Unfortunately, this isn’t very practical for everyday messages, since there’s a limit on the size of the message that can be sent. The best way to secure messages is by using tools that are already out there. Namely, encryption tools that are used properly.