Evaporated Alcohol Can Hide Encrypted Messages

Alcohol has been helping people say what’s on their mind since at least 10,000 BC, according to some historians. Now it can be used to send messages, literally.

British researchers have been working on what they call “molecular communication,” which will allow for wireless transmission of messages in difficult environments such as underwater, in caves, tunnels, oil pipelines, or anywhere else where electromagnetic waves are impractical.

It works by using an encoder, which evaporates liquid alcohol, to disperse molecules through hard-to-reach places. Weisi Guo, an engineer at the University of Warwick who is working on the technology, says that someone with a specially-made decoder can then translate the messages to be read by a human.

“What we’re doing is spraying molecules of chemicals over the air, or underwater, or through something, with different concentrations of sprays that can represent different messages,” he said. “It’s not any different than a mobile phone or other encryption-decoding system, but instead of using electromagnetic waves, we’re using molecules.” The prototypes run using off-the-shelf electronics that cost less than $100.

The system works like morse code or a binary system, according to Guo, who explained how it all works in a study published Wednesday in PLOS ONE. Guo says the first message, sent by his colleagues at York University in Canada, was “O Canada.”

“We have an electronically controlled spray, that sprays what is essentially a string of ones and zeroes,” he said. “Ones are on and zero if off, and the decoder translates that.”

It’s similar, he says, to the ways that animals communicate with pheromones. His system has a few obvious limitations, though some could end up being useful features, depending on the application. Because alcohol molecules disperse rapidly, the people communicating will have to be relatively close by, and the nature of the system means that only someone with a decoder will be able to receive the message.

That raises the possibility that people who want to keep their communications away from, say, the NSA, might be interested in using a system like this. The fact that alcohol evaporates quickly also makes the messages inherently temporary.

“Certainly, from a spacial encryption point of view, someone far away won’t be able to intercept these,” he said. “But also, if the opposition doesn’t know you’re using alcohol then it’d be impossible for them to know what you’d be saying. Right now, someone who is trying to sniff out messages is using the electromagnetic wave system, so to be using this would be quite unexpected.”

Molecular messaging also has applications in dangerous work environments. Often, people who work in mines, underwater, or in tunnels often have no good way of communicating wirelessly—cell signals don’t exactly work well underground. But with molecular messaging, someone working in a mine could quickly send a warning message that would disperse throughout the entire cavern. Guo says his team has set up a company to explore the possibility of making this a commercially-available technology, and is already working with coal mining companies in China to use this for accident reporting and personal safety uses there.

“The challenge with see with these confined environments is that messages don’t always propagate there,” he said. “Because of the nature of diffusion, we’re able to do that.”