Researchers have figured out a way to embed encryption into typed blocks of text on paper. Their secret weapon? Helvetica and Times New Roman. Fonts have been transformed into encryption tools. A new paper by a group of researchers at Columbia University details a method for making tiny changes to fonts that the human eye can’t detect but that look entirely different to a computer vision algorithm. A demo of the technology, dubbed “Fontcode,” shows how they were able to embed the secret message “Hello World!” into a paragraph taken from The Lord of the Rings.
The researchers use an algorithm from previous research that can slowly shift letter forms from one typeface to another to make tiny changes in the shape of every letter that the human eye can’t detect. That could make an “h” slightly thicker in the stem,” or the curve of a “j” slightly sharper.
Once they had these “perturbed” letters, the researchers could make 52 variations of each letter. Each of the 52 variations corresponds to every other lowercase and capital letter in the alphabet (and theoretically every numeral and punctuation mark as well). These 52 variations for each letter go into what the researchers call a “code book” that helps the computer match the perturbed letter it sees with the secret letter it’s encoding. Check it out: