Null Cipher

Extracts a message hidden in cover text: a letter position in each word, line or sentence (or a cycle such as 1,2,3), every n-th letter or word, the letter after each punctuation mark, or the capitals; Scan ranks 34 common readings by English score, and the letters used are highlighted. Augustine (City of God XVIII.23) quotes an acrostic, Sibylline verses whose line initials spell “Jesus Christ, Son of God, Savior”.

• Augustine, The City of God, Book XVIII, ch. 23, trans. M. Dods (1887), New Advent
• David Kahn, The Codebreakers: The Story of Secret Writing (New York: Macmillan, 1967)