Author:
Štefan Porubský
Title: Application and misapplication of the Czechoslovak STP cipher during WWII (report on an unpublished manuscript)
Abstract. Lieutenant colonel Karol Cigáň (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 insignificant and substandard command position at a district military administration in Slovakia.
His cryptographic experience was of no use in his new position.
To profit from his previous experience as a high qualified cryptographer 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 send them to archives.
Unfortunately only one (in two copies) and a collection of small notes survived.
The~aim of~this paper is to make decisive technical parts of manuscript
[K. Cigáň: \textit{Impacts of the decryption of the cipher system of the Czechoslovak Ministry of Defence in London from the years 1940–1945 on the resistance movement}.
Archive of the Slovak National Uprising, Banská Bystrica, Slovakia, Document collection (Fond) V, manuscript no. S36/90, 46 pp.]
about the usage of the so-called STP cipher accessible. Thereby we complement the paper
[Š. Porubský: \textit{STP cipher of the Czechoslovak in-exile Ministry of Defence in London during WWII,}
in: Proc. of EuroHCC '17, 3rd European Historical Ciphers Colloq., Smolenice Castle, Slovakia, 2017 (J. von zur Gathen et al., eds.),
Slovak Univ. of Technology in Bratislava, 2017, pp. 47–66]
where the part of this manuscript containing Cigáň's method for solving STP cipher which he calls ``mathematical'' is published.
To put Cigáň 's analysis and comment into their historical framework we briefly outline the history
of Czechoslovak military intelligence activities with emphasis on their cryptological component.
Keywords: STP cipher, Josef Růžek, Karol Cigáň, František Moravec, Czechoslovak military cryptography, World War II
Mathematics Subject Classification: Primary: 01A60; Secondary: 01A70, 01A85
PORUBSKÝ, ?.: Application and misapplication of the Czechoslovak STP cipher during WWII (report on an unpublished manuscript), Tatra Mt. Math. Publ. 70 (2017), 41–91
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