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Decipherment of a German encrypted letter sent from Sigismund Heusner von Wandersleben to Axel Oxenstierna in 1637
(Tartu University Library, 2024) Waldispühl, Michelle; Kopal, Nils; Waldispühl, Michelle; Megyesi, Beáta
We present our work on an encrypted letter from the Thirty Years’ War written by the ally of the Swedish Empire, Sigismund Heusner von Wandersleben in 1637 and sent from Kassel to the Swedish High Lord Chancellor Axel Oxenstierna. We describe our analysis of the ciphertext including information on the cipher type, the process of cryptanalysis and challenges for the decipherment. We include the edition of the letter in the current state of decipherment and summarize its content.
Post-quantum trails: an educational board game about post-quantum cryptography
(Tartu University Library, 2024) Vakarjuk, Jelizaveta; Snetkov, Nikita; Waldispühl, Michelle; Megyesi, Beáta
Post-quantum cryptography has gained more and more attention with the recent developments in quantum technology. There are already standard drafts for the novel post-quantum crypto systems and organisations are starting the process of migration to post-quantum cryptography. However, the migration process has many challenges that need to be taken into account. Moreover, the algorithms themselves have become more complicated, making it more difficult to educate people about post-quantum cryptography. We propose to use gamification to make it easier to explain the main challenges and obstacles as well as the main steps of the migration process to the non-cryptographic community. We propose a board game that is built using the gamification taxonomy of Toda et al. to ensure a smooth learning process.
Cryptology and redaction – a strange symbiosis
(Tartu University Library, 2024) Turing, Dermot; Waldispühl, Michelle; Megyesi, Beáta
This paper explores the relationship between cryptology and redaction. Redaction can be a frustration to historical cryptology research. Examples of redactions of historical papers relevant to cryptology are presented. It is concluded that the practice of redaction is often ineffective and the policy rationale behind redactions difficult to understand.
Development of the Block Cipher LAMBDA1 in 1990
(Tartu University Library, 2024) Stephan, Winfried; Waldispühl, Michelle; Megyesi, Beáta
In 1990, it became apparent that the German Democratic Republic (GDR) would leave the socialist community of states. This involved the gradual reduction of cooperation between the cipher services of these countries and the separation of cipher connections. LAMBDA1 is a block cipher developed in East Germany in 1990. It was designed for a cipher device for which a Soviet algorithm was originally intended. The plan was to use a predecessor of the Soviet block cipher algorithm, called GOST. This now had to be replaced. The aim was to provide a cipher algorithm that could not be easily decrypted by either the Warsaw Treaty countries states or the NATO countries. The background to these considerations was the assumption that the GDR would confirm to exist as an independent state for an extended period in a kind of transitional phase. The article describes the circumstances under which the LAMBDA1 algorithm was developed in just one month. It was based on the results of previous projects and was then intensively analyzed. The project was only abandoned when it became clear that the unification of the two German countries would take place at short notice and was imminent. The algorithm below is described only to the extent necessary to understand the development process.
Subtle Signs of Scribal Intent in the Voynich Manuscript
(Tartu University Library, 2024) Steckley, Andrew; Steckley, Noah; Waldispühl, Michelle; Megyesi, Beáta
This study explores the cryptic Voynich Manuscript, by looking for subtle signs of scribal intent hidden in overlooked features of the “Voynichese” script. The findings indicate that distributions of tokens within paragraphs vary significantly based on positions defined not only by elements intrinsic to the script such as paragraph and line boundaries but also by extrinsic elements, namely the hand-drawn illustrations of plants.
The Keys of Diplomacy. The encrypted correspondence of Saxon-Polish Ministers Wackerbarth and Flemming 1700-1720.
(Tartu University Library, 2024) Rous, Anne-Simone; Waldispühl, Michelle; Megyesi, Beáta
In the Great Northern War (1700-21), the two most important ministers of August II of Poland, Count of Flemming and Count of Wackerbarth, regularly exchanged reports and communications. Several passages of their correspondence are encrypted. Based on examples from the years 1700, 1706, 1715, 1717, and 1720s, this paper presents tentative results of the first phase of a project aimed at analyzing the entire correspondence from 1698 to 1728. Key questions concern differences in the structure of the ciphers and the efforts involved in decryption. New research perspectives are outlined, such as how ciphers are reused and how cryptography and steganography were combined. The examination of encrypted passages provides insights beyond the facade of 'August the Strong’.
Musician Cryptologists: The Band of the USS California at Pearl Harbor and Beyond
(Tartu University Library, 2024) Prescott, Kyle; Waldispühl, Michelle; Megyesi, Beáta
Working from the basement of US Pacific Fleet Headquarters in Pearl Harbor from 1941, a small team of navy cryptanalysts and linguists known as the Combat Intelligence Unit (CIU) provided the US Pacific Fleet Command with timely details of the capabilities and intentions of the Japanese Imperial Navy (IJN) in the Pacific. A substantial portion of the CIU was comprised of 20 enlisted musicians of US Navy Unit Band 16, the band of the USS California (BB-44), who survived the sinking of their ship in the attack of December 7, 1941. The musicians were recruited to Combat Intelligence, retrained to perform tasks related to the deciphering of Japanese Naval Code JN-25b, and contributed to that unit’s celebrated intelligence successes of 1942. As the war waged on, several musicians from Band 16 transferred to the Naval Communications Complex at Nebraska Avenue in Washington DC, and three eventually joined the National Security Agency (NSA) and served through the height of the Cold War.
Bringing Cryptology into the Secondary Education Classroom
(Tartu University Library, 2024) Murphy, Catherine; Wootton, Aaron; Waldispühl, Michelle; Megyesi, Beáta
Cryptology is becoming increasingly commonplace in undergraduate mathematics curricula as a way to motivate abstract mathematics. However, it is still typically absent in secondary education (students aged 11 to 18). In the following, we discuss why we think it would be advantageous to bring cryptology, both historical and modern, to the secondary education classroom. Additionally, we discuss some of the barriers we perceive to doing so and suggest, in our opinion, how they might be overcome. We illustrate implementation with a specific example of a topic in cryptology that could be included in a secondary education classroom.
Cryptanalysis of Hagelin M-209 Cipher Machine with Artificial Neural Networks: A Known-Plaintext Attack
(Tartu University Library, 2024) Mikhalev, Vasily; Kopal, Nils; Esslinger, Bernhard; Lampesberger, Harald; Hermann, Eckehard; Waldispühl, Michelle; Megyesi, Beáta
This paper introduces a machine learning (ML) approach for cryptanalysis of the ciphermachine Hagelin M-2091. For recovering the part of the secret key, represented by the wheel pins, we use Artificial Neural Networks (ANN) which take as input the pseudo-random displacement values generated by the internal mechanism of the machine. The displacement values can be easily obtained when ciphertext and plaintext are known. In particular, we are using several distinct ANNs, each recovering exactly one pin. Thus, to recover all the 131 pins, we utilize 131 model seach solving a binary classification problem. By experimenting with various ANN architectures and ciphertext lengths, ranging from 52 to 200 characters, we identified an ANN architecture that outperforms others in accuracy. This model, inspired by the architecture by Gohr used for attacking modern ciphers, achieved the following accuracies in recovering the pins of the first wheel of the machine: approximately 71% for 52-characters sequences, 88% for 104-characters, 96% for 200-characters. The first wheel has the largest size and hence represents the most complicated case. For the other wheels, these accuracies are slightly higher. To the best of our knowledge, this is the first time when ANNs are used in a key-recovery attack against such machines.
A Typology for Cipher Key Instructions in Early Modern Times
(Tartu University Library, 2024) Megyesi, Beáta; Láng, Benedek; Kopal, Nils; Mikhalev, Vasily; Tudor, Crina; Waldispühl, Michelle; Waldispühl, Michelle; Megyesi, Beáta
We present an empirical study on instructions found in historical cipher keys dating back to early modern times in Europe. The study reveals that instructions in historical cipher keys are prevalent, covering a wide range of themes related to the practical application of ciphers. These include general information about the structure or usage of the cipher key, as well as specific instructions on their application. Being a hitherto neglected genre, these texts provide insight into the practice of cryptographic operations.