MECHANICAL CIPHER

ABSTRACT:

We present a brief study of the mechanical cipher systems used in the Spanish Civil War (1936-1939). This research is based on original documents obtained from various archives. We do not address the manual methods of ciphering that were more frequently used in the fighting nor the mechanisms of simple ciphering, methods like the strip cipher, the R cipher or the RF cipher [10]. We make a brief description of the cipher device used by the Nationalist army, more commonly known as the "Clave Norte" or "North Key".

KEYWORDS: Enigma Machine, Kryha Machine, Clave Norte, North Key, Spanish Civil War, Legion Condor.

INTRODUCTION

We present a short study of the ciphering systems used by the adversaries in the Spanish Civil War (1936-1939). We do not address the manual systems used. All the systems studied in this article are documented and for this reason we do not mention the Russian cipher methods. However, recently in a Russian company's web page [8], there is mention of the use in Spain of a machine known as M-100, but there are no records of the use of this machine.

BACKGROUND

On the 17 July 1936, at 5 p.m., the Spanish troops initiated a coup in Africa, that was then followed up in practically all of Spain. The military coup having failed, the Spanish Civil War began.

On the 29 September 1936 the Nationalists decide to unify, naming General Franco as the Head of Government and General of the all the forces, celebrating his investiture on the 1st of October in the city of Burgos.