/steg-ə-NAW-grə-fee/. noun. Secret writing. Concealing a secret message within another visible (or otherwise perceivable) message. From the Greek steganos (covered) + the Latin suffix -graphy (written)
In the late 60s, photographer Diane Arbus, who with her camera explored the long-angles of the ever-so-slightly off-kilter dimensions of being human, said:
A picture is a secret about a secret, the more it tells you the less you know.
Today, Arbus’s wise words turn out to be literally true thanks to the explosive growth of digital photography and the practice of steganography. Steganography, from the Greek steganos (covered) + the Latin suffix -graphy (written) is the practice of concealing a secret message within another visible message…kind of the matryoshka nesting doll of secret codes. Steganographic methods range from dots next to words in books or hiding Morse code within the yarn of a knitted document to text or even other media tucked ingeniously inside digital photos and music.
The word steganography itself dates back to Johannes Trithemius’s Steganographia of 1499, a three volume treatise on magic and communicating with spirits that, when decoded—and the third volume wasn’t deciphered until 1996!—is also an exploration of cryptography and steganography. Trithemius was an intriguing character. In addition to being a lexicographer and occultist (to this day the Steganographia remains a standard occultist reference), he was also a Benedictine abbott and historian who became famous for both his eloquence and his unfortunate tendency to insert fictional passages into his historical work. Trithemius did his reputation no favors with his Steganographia—though I could argue he really boosted his modern brand. The book was immediately rejected, ordered burned by Frederick the Wise in the early 1500s and then formally banned by the Catholic Church in 1609, listed in the Index Librorum Prohibitorum along with such august company as John Milton, Francis Bacon, Copernicus and Galileo, to name just a few, where it remained for nearly 300 years.
Examples of pre-digital steganography go back more than 2500 years, when Histaeus, a Persian tyrant back in the day when “tyrant” simply meant an authoritarian leader, shaved a servant’s head, tattooed a message on his scalp, and then waited for the hair to grow back before sending him across the country to his nephew where another shave revealed the secret missive. Spartan steganography, though invented at around the same time, was much quicker. They would write a message on a strip of paper wrapped in a spiral around a wooden cylinder called a scytale. Unrolled, the text was meaningless…but rolled back around a scytale of matching diameter by the recipient and the message was revealed.
While the covert activities continued, starting in the early 1800s, the word steganography itself languished, wrongly dismissed as a synonym for cryptography, of which it is just one form. But then the 80s arrived, for me an era of Walkmen, Rubik’s Cubes and Members Only jackets, but most importantly here, gadget-mania and tech-fever…and a range of possibilities for a whole new kind of steganography opened up thanks to personal computers and the digital media they could be used to create and convey. If there were any hidden messages in the tinny voice and chiclet keyboard of my 1980 Speak & Spell, I surely would have discovered them through sheer repetition, but modern steganography had certainly appeared by 1985 when Barrie Morgan and Mike Barney, also known by the nerd-couple nickname “M2B2” created the first documented digital steganographic application.
Modern steganography is all around us. Watermarks or other identifying information are often embedded, invisibly to the human eye, in photographs. Tools are readily available so that even the most technology-challenged would-be Mata Hari can hide images, video, audio, text and documents of all sorts in pretty much any kind of file. Want to hide a note in that funny cat picture you’re about to forward to all those friends your sure have yet to see it? Or conceal that awesome no-knead bread recipe in the latest Skrillex track in case the Atkins police raid your pantry? Done and done.
Nor has physical steganography gone away. Those microdots made famous in early- and mid- 20th century spycraft have given way to larger payloads packed into smaller spaces, such as the tittles of i’s and j’s on printed documents. In fact, according to the Electronic Frontier Foundation’s research, it’s a safe bet that every color laser printer now being manufactured embeds tracking dots and information in every page they print, even if the particulars have not yet been identified and cracked by outsiders. Just ask the so-far-inaptly named Reality Winner, an intelligence specialist accused of leaking a report about Russian interference in the 2016 U.S. elections. Winner remains in jail and the strongest evidence against her is said to include printer tracking dots on a document she allegedly smuggled out her secure workplace.
Steganography tools for we ordinary folks struggling to make our smart phones cooperate invoke scenarios that might seem like nothing but a game aimed at the small set of geeks who are also espionage enthusiasts, but steganography has real world uses…and ramifications. In addition to identifying ownership, tracking theft and exposing forgeries—matters of great importance to the global economy—steganography, like all forms of cryptography, is in active use by good and bad actors around the world. For every terrorist that might use a seemingly innocuous video to share a nefarious message there is someone struggling against, and trying to stay out of the hands of, a repressive regime. And that’s no joking matter.