Solving the Double Transposition Challenge with a Divide-and-Conquer Approach

Lasry, George; Kopal, Nils; Wacker, Arno

doi:10.1080/01611194.2014.915269

Cited by 17 publications

(4 citation statements)

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“…Israeli George Lasry, who was probably the participant with the longest journey, talked about "Cracking Unsolved Historical Ciphers and Challenges." Among other things, he explained how he had broken the Double Columnar Transposition Challenge (George has recently published a Cryptologia article about this work [Lasry, Kopal, and Wacker 2014]). A video of this talk is available online (Lasry 2015).…”

Section: Talks On Daymentioning

confidence: 97%

Review of the 15th NSA Cryptologic History Symposium

Schmeh¹

2016

Cryptologia

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Section: Talks On Daymentioning

confidence: 97%

Review of the 15th NSA Cryptologic History Symposium

Schmeh¹

2016

Cryptologia

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“…A modern approach to solve the double transposition in general was presented in (Lasry et al, 2014). It is not clear, whether it can be used to solve triple transpositions as well.…”

Section: Ciphers Xq and Rmentioning

confidence: 99%

Diplomatic Ciphers Used by Slovak Attaché During the WW2

Antal

Zajac

Grošek

2020

Linköping Electronic Conference Proceedings

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Slovakia was an allied (puppet) state of Germany during WW2. In various Slovak and Czech archives, we found previously unknown details about diplomatic ciphers used by the Ministry of Foreign Affairs during WW2 in Slovakia. Here we present cipher systems used by Slovak Attaché and give insight into the encryption problems of the Ministry and embassies. 1 The Slovak State name was officially used between March 14 and July 21, 1939. In July 21, 1939 the Slovak State was declared as a republic and renamed to Slovak Republic. The Slovakia acronym was also in use.2 Overview of the Slovak military ciphers used during the WW2 can be found in (Antal et al., 2019).

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“…His primary interest in cryptographic research is the application of specialized optimization techniques for the computerized cryptanalysis of classical ciphers and cipher machines. Using such a technique, he solved in November 2013 [13] the Double Transposition (Doppelwürfel) cipher challenge which was published by Klaus Schmeh in 2007.…”

Section: About the Authorsmentioning

confidence: 99%

Ciphertext-only cryptanalysis of Hagelin M-209 pins and lugs

Lasry

Kopal

Wacker³

2015

Cryptologia

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The Hagelin M-209 was a mechanical encryption device used by the US Army during World War 2 and the Korean War, as well as by other armies and in embassy settings. In this paper, we present a 4-stage hillclimbing algorithm for recovering the full key settings from ciphertext only. The two first stages are based on a divide-and-conquer approach developed by Geoff Sullivan. In our performance evaluation, we show that our method is able to recover key settings from messages as short as 750 letters, compared to 2 000 − 2 500 letters with prior methods. With this method, we solved several M-209 ciphertext-only challenges, including the final exercises in W. Barker's 1977 book, Cryptanalysis of the Hagelin Cryptograph.

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Solving the Double Transposition Challenge with a Divide-and-Conquer Approach

Cited by 17 publications

References 1 publication

Review of the 15th NSA Cryptologic History Symposium

Review of the 15th NSA Cryptologic History Symposium

Diplomatic Ciphers Used by Slovak Attaché During the WW2

Ciphertext-only cryptanalysis of Hagelin M-209 pins and lugs

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