Millions of Millions of Distinct Orders: Multimodality in Seventeenth-Century Cryptography Manuals

Manuscript and print, until recently assumed to be the textual products of two divided cultures that collided in a kind of duel that print won, shared space on the pages of unlikely texts in the mid to late seventeenth century: the codes circulated by plotting assassins, paranoid politicians, and secret lovers. Puzzling alphabetic, numeric, and even geometric figures, handwritten and printed with meticulous typographical attention, often worked clandestinely together in the interest of national or personal security to create complex codes. A number of handwritten messages from the period have survived that use obvious coding practices like the substitution method, such as in collections of letters by Thomas Scot as well as by Royalists known to have gathered and relayed intelligence. David Underdown famously deciphered a number of Royalist documents conveyed before the 1655 rising in his Royalist Conspiracy in England 1649-1660 (1960), noting that "a large number of undeciphered letters can be found on which the historical detective may exercise his ingenuity" (341).¹ Certainly, the practical use of cryptography is exciting, particularly during and after the English civil wars, and a number of historians, like David Kahn, have written popular surveys of the military and political influences of the codes that circulated during the period.² What most known codes in the archives share is their style: they use variations of the substitution method in which letters or words are replaced by numbers or other letters or words according to a key that is kept separate from the message. These more recognizable codes, too, are handwritten.

Less frequently studied are the many cryptography manuals printed for the general public, including John Wilkins's Mercury; or, The Secret and Swift Messenger (1641), which will be the focus of this essay.³ Cryptography manuals of the seventeenth century, like Wilkins's, have typically been scrutinized by historians merely as source material for tracing the growing (or stagnating) sophistication of cryptographic innovations. They have rarely been read closely as self-reflexive objects and commentaries on the developing relationship between the different media they depend upon, represent, and manipulate. Unlike most secret messages that have been identified in the archives, instructional manuals develop codes for use in print publication as well as in handwritten epistles and make those codes publicly accessible. And unlike the exercises in ingenuity that Underdown successfully completed, Wilkins's Mercury advocates for a less visually noticeable method, a method involving multiple media that is at once infallibly secret and incalculably swift.⁴ For cryptographers like Wilkins, script and print had greatest security potential as collaborative, not opposing or even separate, practices, and he used the two media together to test reader understanding of the generic conventions of instructional writing manuals. At the same time that he taught readers how to read and write code, he challenged their abilities to see beyond the codified structures of genre and medium.

The emergent genre of the cryptography manual demonstrates a writing process always necessarily multimedia in nature. Visually, sample codes in Wilkins's Mercury exhibit both handwritten and typographical parts. Later writers like John Falconer, author of Cryptomenysis Patefacta: Or The Art of Secret Information Disclosed without a Key (1685), reproduce Wilkins's handwritten codes in the printed italic and so flatten Wilkins's lessons into a single medium, oversimplifying strategies that made Wilkins's codes innovative and practically effective.⁵ Yet despite this difference, Cryptomenysis Patefacta, as well as Samuel Morland's A New Method of Cryptography (1666), shares with Mercury its emphasis on the role that handwriting plays in the encryption and decryption processes.⁶ Each of these cryptographers also purposefully exploits the inconsistencies and errors inevitable in printed texts, celebrating the diversity of all written media and exposing as naive any assumption that print is somehow flawless or less prone to variation than script. Working through these types of collaboration in the codes themselves and their explanations, in the processes of encryption and decryption, and in the peripheries of the printed page, I find that cryptographers, most particularly Wilkins, were not only conscious of the perceived competition between print...