An harmonious encoding of instrument values by a 19th century Parisian violin dealer

Jean-Philippe Échard (1, 2) , Pierrick Gaudry (3)

1 CRC - Centre de Recherche sur la Conservation
2 Cité de la musique-Philharmonie, Musée de la musique, Equipe Conservation Recherche
3 CARAMBA - Cryptology, arithmetic : algebraic methods for better algorithms

The study of three ledgers from the archives of a prominent Parisian violin maker's workshop (active from 1796 to 1948) reveals that some of their content was encrypted. We present here the deciphering of the code, and a discussion of its use in the context of the workshop. Charles-Adolphe Gand introduced this code around 1847 to encrypt values of antique/used violins he would buy and resell. His successors maintained the use of this code at least until 1921. Taking a few examples of instruments by Stradivari and other violin makers, we illustrate how the decoded ledgers –listing transactions for more than 2,500 instruments– are of high interest as historical sources documenting the margins, rebates, and commercial practices of these violin dealers. More generally, will contribute to better describing the evolution of the market for antique instruments of the violin family.

Mots clés: Violin Trade; Charles-Adolphe Gand; Monoalphabetic Substitution Cipher

Domaines: Cryptographie et sécurité [cs.CR]

Jean-Philippe Échard, Pierrick Gaudry. An harmonious encoding of instrument values by a 19th century Parisian violin dealer. Cryptologia, 2017, 41 (5), pp.448-458. ⟨10.1080/01611194.2016.1257524⟩. ⟨hal-01393625⟩