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Cardan grille
grille The Cardan grille is a method of writing secret messages using a grid. History[edit] This technique was used in ancient China.[1][additional citation(s) needed] In 1550, Girolamo Cardano (1501–1576), known in French as Jérôme Cardan, proposed a simple grid for writing hidden messages.
Educated men in 17th century Europe were familiar with word games in literature, including acrostics, anagrams, and ciphers. An encipherer places the grille on a sheet of paper and writes his message in the rectangular apertures, some of which might allow a single letter, a syllable, or a whole word. Stilted language draws attention to itself and the purpose of the Cardan grille is to create a message “without suspicion”[ citation needed] in the words of Francis Bacon.
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