A detail of a page from Johannes Trithemius, Polygraphiae libri sex , 1518, exercises in cypher alphabets in the first published study of encrypting information.
Blaise de Vigenere, Traicté des chiffres , Paris 1586 . Here the message is hidden among the stars and is decoded with a shared text.
Giovanni Della Porta, De Furtivis Literarum Notis Vulgo published by the great esoteric in 1591.
a figure from John Wilkins' Mercury, or, The secret and swift Messanger; shewing how a man may with Privacy and Speed communicate his Thoughts to a Friend at any distance , London 1641, and a comprehensive account as to how messages may be concealed in words, music, and here geometry.
a spoof inscription
see Dickens' satire in
Bill Stumps his mark
"Beneath this stone repose...
Tripe Seller" 1756