SoylentNews

hubie [soylentnews.org] writes:

Concealing messages with chemicals is an ancient idea going back to invisible inks [bookbindersmuseum.org] developed in the days of Pliney the Elder. However, those messages are only hidden and are easily revealed with the application of light, heat, or other chemicals. Chemists from the Weizmann Institute of Science have created a chemical encryption method [rsc.org] using fluorescence.

In this case, Margulies’ Enigma machine is a fluorescent amino acid scaffold that can bind to various compounds. First, the sender converts a message into a code, with each letter represented by a number. They then dissolve the fluorophore sensor in ethanol and record the fluorescence emission spectrum after adding a random chemical. The intensity values of the spectrum (measured at every 20nm) can be used as a unique encryption key, which, when added to the initial code numbers, can be sent as an encrypted message to the recipient.

‘To be able to read the message, the receiver simply needs to add the same chemical to an identical molecular device,’ Margulies explains. The added chemical and solvent are the initial conditions necessary for decryption, like the rotors in the Enigma machine. After adding the correct chemical, the recipient can measure the fluorescence emission spectrum and subtract the emission values from the cipher code to read the message.

Abstract from the open access article [nature.com] (doi:10.1038/ncomms11374):

Since ancient times, steganography, the art of concealing information, has largely relied on secret inks as a tool for hiding messages. However, as the methods for detecting these inks improved, the use of simple and accessible chemicals as a means to secure communication was practically abolished. Here, we describe a method that enables one to conceal multiple different messages within the emission spectra of a unimolecular fluorescent sensor. Similar to secret inks, this molecular-scale messaging sensor (m-SMS) can be hidden on regular paper and the messages can be encoded or decoded within seconds using common chemicals, including commercial ingredients that can be obtained in grocery stores or pharmacies. Unlike with invisible inks, however, uncovering these messages by an unauthorized user is almost impossible because they are protected by three different defence mechanisms: steganography, cryptography and by entering a password, which are used to hide, encrypt or prevent access to the information, respectively.

Original Submission