The Hazards of Cryptology

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David Kahn called it the Yardley Symptom, the compulsion of the cryptologist to chip away at the puzzle throughout his waking moments. He turns the letters over in his mind even as he fries his morning egg, scrubs his evening dishes.

Joe Rochefort called it the “the staring process,” his unscientific-sounding method for codebreaking. Look at the symbols. Line them up in various ways. Write them out in various forms. Stare at them. “Pretty soon you’d notice a pattern.”

Elizebeth Smith Friedman called it “the thrill of your life,” the moment a cipher falls apart in your hands, revealing its secrets. “The skeleton of words leap out, and make you jump.”

I just spent an hour and forty-five minutes, over three different sittings, decrypting a simple substitution cipher. I confess, it did not stay with me during the two hiatuses. Not once, as I showered or snacked or drove the car, did I consider a new possibility for that pair of double-letters or those four different three-letter words. Nor, when at the computer, did I stare stop and stare deeply, though I did examine the patterns, over and over, trying this letter and that in a vain attempt to gain a foothold. When I did eventually crack the wall, the bricks fell quickly. I can’t say it was the thrill of my life, but it was satisfying, not in the way that puts a smile on your face and a skip in your step, but rather that allows you to breathe easier and release the built-up tension in your muscles. My desperation to read Mark Twain’s quip had grown acute, my frustration approaching all-consuming.


I had inferred the double-l’s early on, but there were so many possibilities: -all, -ill, -oll, and -ell. The contraction “till” eluded me. I “knew” (though I was never really sure of anything) that “off” had to start with a vowel. I tried “odd” and “egg.” I must have tried “off” (Didn’t I?), but I never ruled it in as almost surely the best answer. The “o” gave two -o-o–o- words, which, let’s be honest, didn’t look promising. But it was the puzzle piece that first fell to my “stare.” Once I saw “tomorrow” amid those o’s, there was nothing else to do but plug in letter by letter until the message was complete. This took less than sixty seconds.

A mono-alphabetic substitution cipher (MASC) is the simplest cipher to solve. Cryptographers can layer on another substitution (or more?) to make poly-alphabetic encryptions. Fractionating is a particularly devilish way of transposing the letters of numbers in a cipher. When the symbols are shifted to different positions in one or more ways, they produce a transposition cipher. Layer on a second shift, and you get a double transposition cipher. Use an electromechanical machine with rotors that scramble the symbols multiple times in random, non-repeating ways, and you get a cipher that was, in the 1920s, quite possibly unbreakable.

Early in the decade, William Friedman solved the single-rotor Hebern cipher machine single-handedly in six weeks. In the 1930s, it took Friedman’s team of SIS cryptographers (Signal Intelligence Service) several years to crack the Japanese Type A Cipher Machine, code-named Red.  Ditto the upgraded Type B machine, Purple. Elizebeth Friedman’s biographer described the process as “akin to building a watch if you have never seen a watch before, simply by listening to an audio recording of the ticking and clicking of its gears.” Neither the Nazis or the Japanese Imperials cracked Friedman and Rowlett‘s four-rotor SIGABA machine before the end of the war.

The staring, the lining up and relining up, the round-the-clock mental demands for professional cryptographers don’t last an hour-and-three-quarters over two days. The frustration, the thwarting, the not-knowing persist day-in and day-out–sixteen- to twenty-hour days–for months and even years. The pressure builds.

Joe Rochefort said, “If you desire to be a real great cryptanalyst, being a little bit nuts helps.”

William Friedman seconded him, saying it was “not necessary” for a cryptanalyst to be insane, “but it helps.”

This highly cerebral profession took a surprising large physical and mental toll on its earliest practitioners. After cracking the Japanese diplomatic code and deciphering what he claimed were more than five thousand messages before and during the Washington arms control conference of 1921-22, Herbert Yardley was “exhausted to the point of breakdown.” His doctor ordered him to Arizona for several weeks to recoup. Later in the decade, Rochefort developed ulcers from the stress, a condition he lived with for the rest of his life. William Friedman, likely predisposed to mental illness, suffered depression to the point of hospitalization. Elizebeth Friedman chain-smoked and had difficulty keeping her weight.

Notwithstanding the occupational hazards, both Friedmans turned to cryptology in their play. They wrote ciphers to their children and friends. They held cipher parties, the way some hold Super Bowl parties today–with the guests interacting with puzzles and cryptograms rather than with an over-hyped athletic contest on a screen. It would have been fun to be a guest at one of these, with neither the extreme difficulty nor the life-altering stakes approaching those of Friedman’s work–work the Friedmans could not help bringing home in their minds yet could never discuss with each other.

If that is not a recipe for mental stress, I don’t know what is.


Carlson, Elliot. Joe Rocheforte’s War: The Odyssey of the Codebreaker Who Outwitted Yamamoto at Midway. Annapolis, Naval Institute Press, 2011.

Fagone, Jason. The Woman Who Smashed Codes: a True Story of Love, Spies, and the Unlikely Heroine who Outwitted America’s Enemies. New York: Harper Collins, 2017.

Kahn, David. The Reader of Gentlemen’s Mail: Herbert O. Yardley and the Birth of American Codebreaking. New Haven: Yale University Press, 2004.

“Reminiscences of Captain Joseph J. Rochefort. U. S. Navy (Retired).” Annapolis: U. S. Naval Institute, 1983. Series of tape-recorded interviews in 1969, Redondo Beach, CA, by Commander Etta-Belle Kitchen

Yardley, Herbert O. The American Black Chamber. Indianapolis: Bobbs-Merrrill Company, 1931.

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