Cardan grille

[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.

Although the original Cardan grilles were little used by the end of the 17th century, they still appeared occasionally in the form of masked letters and as literary curiosities.

George Gordon Byron, for example, claimed to have written Cardan-grille verse – but as a demonstration of verbal skill rather than a serious cipher.

The turning grille reappeared in a more sophisticated form at the end of the 19th century; but, by this time, any connection with Cardano was in name alone.

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.