Hiding messages with molecules

What’s a spy to do when she wants to send a secret message? Maybe she should whip out a fluorescence spectrometer. David Margulies and coworkers at Weizmann Institute of Science show that they can hide messages using the emission spectrum of a fluorescent molecular sensor (Nat. Commun. 2016, DOI: 10.1038/ncomms11374).

The researchers synthesized a molecule with multiple fluorophores and recognition elements. When common chemicals bind to the sensor, they alter the fluorescence spectrum in ways that can serve as an encryption key for hiding messages.

First, the researchers convert a message into numbers using an alphanumeric code. They then encrypt it by taking the emission spectrum of the sensor and a randomly chosen chemical and adding the intensity values at 20-nm intervals to the numbers in the message.

To decrypt that message, the recipient measures the emission of the sensor molecule under the same conditions and subtracts those intensity values from the encrypted message to reveal the original one.

“The encoding technology should find widespread applications in this electronic information age,” says Aijun Tong, an expert on fluorescence spectroscopy and molecular recognition at Tsinghua University. “Its root mechanism of information protection is chemistry rather than simply mathematics or electronics, thus making it immune to most of the current deciphering methods.”