Spy hides messages in bacteria

Instead of using lemonade, in the future intelligence agents can encrypt secret messages with bacteria to send to teammates or superiors.

Colorless toners, lemon juice, are the sorts of fluid used by spies to write messages over the last several decades. Naturally, the intelligence community has come up with a series of ways to decipher messages written in these special types of ink . Finding new ways to hide the message is a constant need in the intelligence world.

A message is encoded by light colors from bacteria. (Photo: Newscientist)

David Walt, a chemist at Tuft University in the US, and colleagues think of using bacteria to hide confidential information. Scientists genetically engineered Escherichia coli to produce fluorescent proteins. Thanks to these proteins, the bacteria emit light in seven colors, the Newscientist said.

Each character of the message is encoded in two colors. Because the light-emitting bacteria have seven colors, the total number of characters that can be encoded is 49 - enough for the alphabet, natural numbers from 0 to 9, and some other symbols.

"You can encrypt all secret intelligence applications with seven colors of bacteria ," Walt said.

The bacteria were raised on a white agar plate before they were transferred to a thin film. Thin film can be sent to the recipient by mail. Under light conditions people do not see anything on the film. But the message will appear when the recipient put the film into a suitable environment so that the bacteria on the film glow.

In addition to making the bacteria glow , Walt's genetic engineering technique also makes it possible for bacteria to only glow in certain environments. For example, if a strain of bacteria is genetically engineered to fight a particular antibiotic, it will only glow when exposed to the antibiotic. When antibiotics were considered the key to deciphering the message, Walt said he could create thousands of such keys by combining some of the bacterial genetic traits.

Scientists can also deprive bacteria of light after a certain period of time, so that they will produce messages that can self-destruct.