The Use of Volvelles in Two Early Modern Cryptography Manuals

Abstract

This paper examines the form and function of volvelles (rotating paper discs) used to represent cipher systems in Giambattista della Porta’s De furtivis literarum notis (1563) and in the French translation of Trithemius’Polygraphia by Gabriel de Collange (1518, transl. 1561). I analyze the use of volvelles in cryptography handbooks within the larger context of their overall function in the Early Modern period, and I identify the factors that may account for an increasing use of volvelles in succeeding editions of della Porta’s and Trithemius’ works in the second half of the 16th century. Collange’s expanded version of Trithemius’ manual and della Porta’s numerous amended editions of his own handbook indicate that changes in the material representation of cipher systems correlate with an increased level of public knowledge about encryption methods.