Readers of a certain age will remember those ‘invisible ink’ spy toys that let you write a ‘secret’ message which would only appear after rubbing the page with half of a lemon.
Yeah, this is not that.
But what if I were to tell you that scientists have found a way to hide a 256-bit cipher key within the molecules of a polymer mixed with ink and then used a handwritten letter to distribute that encryption key?
That is exactly what this is.
It’s also stupidly complicated if you aren’t a science boffin and, dear reader, I am not. So, for those who are, please accept my apologies if I dumb this down in my personal quest to understand and enable me to communicate the findings to the broadest possible audience.
Here comes the molecular cipher key science bit
Here comes the science bit. At the heart of the process is the ability to store information within ‘macro-molecules’ or digital polymers, if you prefer, in the form of a defined monomer sequence. A monomer is a class of molecules that can react with others to form much larger molecules or polymers.
It should be noted at this point that we are talking about very small amounts of data that can be stored this way. This is where the scientists from the University of Texas at Austin come into play. In their paper, ‘Molecular Encryption and Steganography Using Mixtures of Simultaneously Sequenced, Sequence-Defined Oligourethanes,’ the team explains how a 256-bit cipher key was successfully stored. This, the paper suggests, is the largest amount of information to date. The key itself is used to encrypt a separate document, the text of the Wonderful Wizard of Oz book.
The scientific paper is heavy going, but a fascinating read nonetheless
That cipher key itself, a molecular key no less, was first dissolved in isopropanol before being mixed with glycerol and soot. This created a usable ink. A ballpoint pen was then filled with this ink and used to write a letter. For all intents and purposes, this looks and functions like any handwritten document and, as such, is a perfect, if unlikely sounding, medium for transporting secrets.
Recovering the secret key from the handwritten letter
Indeed, the letter itself was posted using a standard mailing service and delivered to a collaborator who had no in-depth knowledge of the process used. They did, of course, have the necessary equipment and basic scientific nous to be able to follow the instructions they had been given. By creating what I like to think of as a ‘secret soup’ dissolving both paper and ink using dichloromethane, the cipher key was separated successfully on the first attempt.
“This paradigm has significant potential for widely accessible molecular information storage and encryption. Future iterations will look to robotically automate the writing and reading processes, furthering its accessibility and practicality for real-world applications,” the paper concludes.
Although this is heavy-going for most of us, the scientific paper is a remarkably fascinating read and well worth the effort. Who knows, in 10 years you might even be able to buy a ‘molecular ink’ spy toy…
