Application and misapplication of the Czechoslovak STP cipher during WWII --- Report on an unpublished manuscript
Abstract
Lieutenant colonel Karol Cig\'a\v n (1921--2005), head of the cryptographic unit of the Czechoslovak Ministry of National Defence in the period 1949--1958 was after discharging from this position in Prague relocated to an insignicant and substandard command position at a district military administration in Slovakia. His cryptographic experience was of no use in his new positions. To prot from his previous experience as a high qualied cryptogra-
pher he started to study the accessible literature and archive materials about the usage of the Czechoslovak cipher systems during the WWII. The result of this his activity were some manuscripts where he deciphered and analyzed some Czechoslovak military wireless telegrams. His critical analysis and his conclusions did not meet an understanding or a positive response of historians and were nor accepted for publication. He had no other chance as to sent them to archives. Unfortunately only one (in two copies) and a collection of of small
notes survived. The aim of this paper is to make accessible decisive technical parts of Cig\'a\v n's manuscript [Cig\'a\v n 1990] about the usage of the so-called STP cipher. Thereby we complement the paper [Porubsk\'y 2017], where the part of this manuscript containing Cig\'a\v n's method for solving STP cipher which he calls `mathematical' is published. To embed Cig\'a\v n's analysis and comment into their historical framework we briefly outline the history of Czechoslovak military intelligence activities with emphasis on their cryptological component.
pher he started to study the accessible literature and archive materials about the usage of the Czechoslovak cipher systems during the WWII. The result of this his activity were some manuscripts where he deciphered and analyzed some Czechoslovak military wireless telegrams. His critical analysis and his conclusions did not meet an understanding or a positive response of historians and were nor accepted for publication. He had no other chance as to sent them to archives. Unfortunately only one (in two copies) and a collection of of small
notes survived. The aim of this paper is to make accessible decisive technical parts of Cig\'a\v n's manuscript [Cig\'a\v n 1990] about the usage of the so-called STP cipher. Thereby we complement the paper [Porubsk\'y 2017], where the part of this manuscript containing Cig\'a\v n's method for solving STP cipher which he calls `mathematical' is published. To embed Cig\'a\v n's analysis and comment into their historical framework we briefly outline the history of Czechoslovak military intelligence activities with emphasis on their cryptological component.