Researchers at Harvard and Tufts Universities have devised a groundbreaking new method of encryption that utilizes color-coded E. coli—the same bacteria that can cause food poisoning—to hide messages decipherable only by using the proper science.

Professor David R. Walt of Tufts University devised the bacterial code SPAM—Steganography by Printed Arrays of Microbes—as a means for scientists to send encoded messages.

According to Walt, the bacteria are color-tagged and then dotted onto a lab dish in a specific pattern that encodes the secret message. Each of the sets of dots in which the bacteria are arranged represents either a number, letter, or symbol.

Messages are sent via pieces of paper that can transfer bacteria in their specific arrangement from one dish to another. By using a particular kind of light and the appropriate antibiotics, the receiver can make the bacteria emit fluorescent light and decode the message.

The project, funded by the U.S. Defense Advanced Research Projects Agency, could potentially revolutionize encryption methods used by both scientific institutions and commercial enterprises, Walt said.

“One of the broadest areas of science and technology is information science,” said chemistry professor George M. Whitesides ’60, one of the scientists behind the new method. “There’s a whole field that describes this with impressive accuracy for bits moving down fiber-optic cables, but when you get into the fields of biology and chemistry, the idea of information encoding becomes less clear.”

Applications of the new encoding system are endless, Walt said. Currently, researchers are considering using the code as a form of secret identification stamped on the exterior of packages.

“A potential application is some kind of secret agent-type communication, but it’s unclear whether that will ever transpire,” Walt said. “The most probable application will be product authentication.”

Walt also mentioned the possibility of a future incarnation of the code similar to the audio recordings in “Mission: Impossible” that would self-destruct after playing.

“We’re researching fluorescent proteins that have shorter lifetimes so they turn on and then fade. So potentially we could have a message fade and then over a period of time a second message could appear,” Walt said.

Whitesides said that the research team is also looking into how to mimic the processing capability of computer programs in non-traditional technologies.

“We’re thinking about how you encode information in biological, chemical, and scientific systems in new ways, and how to manipulate that information in such a way that the information manipulates itself, similar to a program,” he said. “This research is a demonstration of a new idea.”

—Staff writer Matthew M. Beck can be reached at mbeck@college.harvard.edu.