[Adapted from an article “The Construction of Medium-Difficulty Aristocrats” in The Cryptogram, March/April 1992, and reprinted by permission of the author and The Cryptogram.]
 Constructing Medium Difficulty Crypts 
By Oz (a.H. Phelps)

There are many ways to go about constructing medium-difficulty crypts. Mine are personally considered a typical engineer’s automatic, mechanistic approach.


To provide medium difficulty, it is necessary only to avoid those dead giveaways that make obvious entry points.


It takes considerable skill, talent, and work to create a toughie. Therefore, if one has eliminated the entry points and not worked too hard, one has generated a medium-difficulty crypt.

  1. Never use a or I as a word.
  2. Do not use possessives or contractions containing apostrophes.
  3. Avoid two-letter words. Most have longer substitutes. For example, in can be into or inside, according to context.
  4. Avoid three-letter words, especially the and and. The construction _ _ _ _, _ _ _ _ _ _, _ _ _   _ _ _ _ _ _ is an almost certain indicator of and.
  5. Do not use four-letter words with doubled letters. In the middle, they are usually O or E; at the end they are often L or S. Doubled letters in longer words are not as easily identified.
  6. Do not begin a question with an asking word (the WH words, such as what and why; how; can; and may). Change the word order; for example, Ever wonder where . . .
  7. Avoid said, remarked, wrote, and so on before or after a direct quotation. Again, change the word order: Aged professor said . . . can become Aged professor said during lecture, . . .
  8. Do not distort endings. Let -ing, -tion, -ily, -ed, and so on fall where they may. They are likely but not obvious entry points.
 Generating Text

Paraphrase an ordinary message with less common words and combinations, keeping the rules above in mind.

An example is the following paraphrase of “Three Blind Mice”: Sightless rodent trio scampered after rural housewife. Alarmed victim adroitly wielded cutlery, removing caudal appendages. [from The Cryptogram]

It is not necessary to alter letter frequencies. Small samples of English text have widely varying frequencies and do not automatically follow ETAOIN SHRDLU . . .

Check the paraphrased text for adherence to guidelines (at least 18 different letters and no more than six singletons, preferably three or fewer), and correct, if necessary, by changing one or two words. This process is simple, quick, and painless. An example of paraphrasing follows:

“The early bird gets the worm” becomes Early rising avian catches earthworm, appeasing hunger. Perhaps worms should snooze longer.

A8, C2, D1, E8, G4, H5, I4, L3, M2, N6, O6, P4, R8, S7, T2, U2, V1, W2, Y1, Z1. Compare with standard frequencies.

Changing snooze to sleep would reduce the four singletons to three with only a moderate change in the distribution.

If, eventually, you run out of proverbs and rhymes, use any text. I took this sentence from a news article on sunspots and solar activity: “While scientists debate the causes and consequences of solar activity, they agree that we on earth will see a solar maximum in 1990.” This was readily changed to: Scientists argue sunspot causation without agreement, although agree minimum activity likely next year.

Try this paraphrase method and send your constructions to the editor. He deserves all the help we can give him and will be very pleased. Or, Test above method for medium-difficulty crypts, sending joyful, deserving editor your results.

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