PREHĽAD ŠIFIER POUŽÍVANÝCH NA SLOVENSKU POČAS DRUHEJ SVETOVEJ VOJNY: 1. ČASŤ – VOJENSKÉ ŠIFRY

Securing sensitive information is a crucial task nowadays, as well as it was in the past. The importance of using cipher systems became especially evident in times of military conflict. The ability to solve an enemy’s encrypted correspondence influenced the course of wars. Despite historical ciphers being well studied, there are still open questions. The major problem for our work was the unavailability of classified documents in archives. Only in recent decades, some countries (archives) started to declassify old military signal intelligence files, making them available to researchers. In this study, we explore the details of cipher systems used in Slovakia during WW2. The study starts with a brief introduction, focusing on essential milestones of cryptology related to Slovakia. The first section explores secrecy at the beginning of the war. At that time, all ciphers and directives were adapted from former Czechoslovakia. In the second section, a new cipher is introduced that was developed directly in Slovakia and approved by Germany. The third section discusses ciphers obtained from Germany (including the famous cipher-machine Enigma), used mainly during military campaigns. The cipher designed in Slovakia was in use alongside the German ciphers. The fourth section investigates the ciphers used during the Slovak National Uprising. Finally, we evaluate the used cipher systems from today's point of view. All the information about used ciphers presented in this paper is directly from our research results uncovered from the Military History Archive in Bratislava and Central Military Archives in Prague. As far as we know, this study is the first attempt to provide detailed information on this topic in Slovakia.