VIGENÈRE, Blaise de. Traicté des chiffres, ou secretes manières d’escrires.
Paris: Abel L’Angelier, 1587. First edition, second issue.

“The foundation work of modern cryptography” (Huntington). The Vigenère cypher was regarded as unbreakable for over 300 years, until Babbage and Kasiski independently developed a method of multiple tests to carry out a successful cryptanalysis.

“Vigenère became acquainted with the writings of Alberti, Trithemius, and Porta when, at the age of twenty-six, he was sent to Rome on a two year diplomatic mission. To start with, his interest in cryptography was purely practical and was linked to his diplomatic work. Then, at the age of thirty-nine, Vigenère decided that he had accumulated enough money for him to be able to abandon his career and concentrate on a life of study. It was only then that he examined in detail the ideas of Alberti, Trithemius, and Porta, weaving them into a coherent and powerful new cipher … The cipher is known as the Vigenère cipher in honour of the man who developed it into its final form. The strength of the Vigenère cipher lies in its using not one, but 26 distinct cipher alphabets to encode a message… To unscramble the message, the intended receiver needs to know which row of the Vigenère square has been used to encipher each letter, so there must be an agreed system of switching between rows. This is achieved by using a keyword… Vigenère’s work culminated in his Traicté des Chiffres, published in 1586. Ironically, this was the same year that Thomas Phelippes was breaking the cipher of Mary Queen of Scots. If only Mary’s secretary had read this treatise, he would have known about the Vigenère cipher, Mary’s messages to Babington would have baffled Phelippes, and her life might have been spared” (Singh, pp. 46-51).

“The Traicté is reliable in its cryptologic information. Vigenère was scrupulous in assigning credit for material from other authors, and he quoted them accurately and with comprehension… The cipher now universally called the Vigenère employs only standard alphabets and a short repeating keyword – a system far more susceptible to solution than Vigenère’s autokey… In spite of Vigenère’s clear exposition of his devices, both were entirely forgotten and only entered the stream of cryptology late in the 19th century after they were reinvented (Kahn, pp. 146-8).

Vigenere's studies of both Biblical and Rabbinical Hebrew brought him into contact with the Cabbala, which inspired him to write two alchemical works, and - as is obvious from the many Cabbalistic and Hebrew references given in this work - to combinatorics and cryptography.

Macclesfield 2052 (first issue, 1586)

Adams V745 (2 leaves missing); The Huntington Library Quarterly, vol. 28, p.288; Caillet, Manuel bibliographique des sciences psychiques ou occultes, 11159 (first issue); Galland, An historical and analytical Bibliography of the Literature of Cryptography, p. 193; Singh, The Code Book. The Secret History of Codes and Codebreaking, pp. 146-8; Mortimer, French 543; STC French p. 439 (‘imperfect’).

4to: 231 x 162 mm. Eighteenth-century speckled calf, spine richly gilt (lightly worn). On title "Ex libris Abrahami Girard.1666.". Large book plate engraved to verso of title. Ff. 326, cccxxvii-cccxxxvi, 327-343, [3:index]. Tables inserted between leaves 184/185, 192/193, 198/199. Leaf 32 misnumbered as 22, leaf numbers 211-220 omitted from sequence (as the Huntington copy). Leaves CCCXXVII-CCCXXXVI contain the first European representation of the Chinese and Japanese writing--cf. Galland. Title page with some discoloration, otherwise clean throughout, a very good copy.