Steganography: Knowledge Is Powe

My new word of the day is steganography: The hiding of information in an innocuous format. It derives originally from the Greek for “hidden writing”: steganos (στεγανός), meaning “covered or protected”, and graphein (γράφειν) meaning “to write”. What makes it an extra-sneaky art, as opposed to plain old encryption, is that a steganographic message isn’t obviously a code. It can pass as an Internet avatar, a pixellated image, a Sudoku game, or a class graduation photo.

This last is what initially caught my attention, from an article in the estimable Cabinet entitled How to Make Anything Signify Anything. It’s the tale of a photograph, taken in 1918, of a cadre of cryptographers who had just finished their training in a crash course led by Colonel William F. Friedman and his wife Elizebeth. Friedman, who had originally studied plant biology, was imported to work in eccentric cotton heir George Fabyan’s Illinois think tank on wheat propagation. But he fell in love with Elizebeth Smith, a cryptographer and Elizabethan scholar who was head of the “American Academy of Baconian Literature,” and they ended up working together to train recruits in cryptanalysis intelligence for the Great War.

The Elizabethan connection, and their area of concentration, was a code called a biliteral cipher, invented by none other than Sir Francis Bacon in the late 1570s. It’s essentially written in binary, using a system of five placeholders in either of two values for each letter of the alphabet: A = aaaaa, B = aaaab, C = aaaba, D = aaabb, etc. But instead of the now-familiar binary 1′s and 0′s, “a” and “b” can be represented by anything at all—“pluses and minuses, flowers of different kinds or colors, even (literally) apples and oranges.” Therefore the cover code could contain any message written in a combination of two different fonts, or bold-face and regular characters, which, when broken down into groups of five, would translate into the Baconian cipher. The only key needed to solve it is knowing which is which. Thus the example in the Cabinet article reads as follows:

brooklyn ny

aabbb abaaa

h i

And that’s what makes the concept so tantalizing. Cabinet gives us a couple more examples—an innocuous-looking page of sheet music, where the notes representing “b” have tiny gaps between two of the staff lines, and a fantastic botanical drawing of a flower in which the variables consist of differently shaped petals, leaf veins and roots. The sheer craziness of possible variations, and the fact that the codes don’t read as codes, are what make the system wonderful:

It is unlikely that Bacon’s cipher system was ever used for the transmission of military secrets, in the seventeenth century or in the twentieth. But for roughly a century from 1850, it set the world of literature on fire. A passion for puzzles, codes, and conspiracies fueled a widespread suspicion that Shakespeare was not the author of his plays, and professional and amateur scholars of all sorts spent extraordinary amounts of time, energy, and money combing Renaissance texts in search of signatures and other messages that would reveal the true identity of their author.

In the case of Friedman’s photo, the individuals facing the camera were the a’s, and the ones looking away the b’s. The message spelled out was “Knowledge is Power.” Or rather, since they were four people short, “Knowledge is Powe” (a decoded version can be found here).

The photograph was an enduring reminder, then, of Friedman’s favorite axiom—and he was so fond of the phrase that some fifty years later he had it inscribed as the epitaph on his tomb in Arlington National Cemetery. It captures a formative moment in a life spent looking for more than meets the eye, and it remained Friedman’s most cherished example of how, using the art and science of codes, it was possible to make anything signify anything.

The modern study of steganography goes far beyond group photos and fonts, to include encrypted pixellated photographs and data compression. But it’s the old-fashioned, grass-roots applications that strike my fancy, and make me wish for a secret clubhouse—or even a secret.


3 Comments to Steganography: Knowledge Is Powe

  1. Titus's Gravatar Titus
    February 23, 2011 at 11:40 am | Permalink

    Fascinating. I have a few Enigma types that will really enjoy this. Also might have to plan this into the next group photograph I plan!

  2. nethmi's Gravatar nethmi
    March 11, 2011 at 6:48 am | Permalink

    Are steganography and the encoding (pub key & pub key) equal?

    I rad a article in

    it says it is equal but i’m not sure.

    what is your opinion.

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