Browsing by Author "Megyesi, Beáta"

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A new perspective on Dutch WWI codebreaking with its international ramifications
(Tartu University Library, 2024) Jacobs, Bart; van Kampen, Florentijn; Waldispühl, Michelle; Megyesi, Beáta
During the First World War, the Netherlands maintained a stance of carefully guarded neutrality. International tele communications in the form of telephone and telegraph were closely monitored and censored by so-called censorbureaus. In 2019 new files were declassified and released to the Dutch National Archive about the secensorship bureaus at Amsterdam and Rotterdam, covering 1914 to 1918. They provide detailed insight in the day-to-day business, the codebreaking efforts and specific cryptanalytic results. The material provides a completely new perspective on the genesis of modern Dutch codebreaking. This article gives a first survey of the development of these interception bureaus. It analyses their pioneering codebreaking activities and presents historic material on German diplomatic ciphers. Also, it provides new insight into the mysterious sale in 1919 of German codebooks from the Netherlands to the United States, as reported earlier in the literature.
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.
Active learning for sense annotation
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 245--249, 2015) Martínez Alonso, Héctor; Plank, Barbara; Johannsen, Anders; Søgaard, Anders; Megyesi, Beáta
Adapting word2vec to Named Entity Recognition
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 239--243, 2015) Katharina Sienčnik, Scharolta; Megyesi, Beáta
An early French digit cipher: deciphering a letter from the King of France to the Duke of Nevers (1592)
(Tartu University Library, 2024) Desenclos, Camille; Lasry, George; Waldispühl, Michelle; Megyesi, Beáta
We deciphered a single letter written in 1592 by Henry IV, King of France, to Louis de Gonzague, Duke of Nevers, held in the Bibliothèque Nationale de France (BnF). The ciphertext mostly consists of contiguous digits, and demonstrates an early use of digit ciphers in 16th-century France. In this letter, Henri IV exposes some parts of his current military strategy against the Catholic League. After deciphering the letter, we were able to locate the original cipher table in another BnF manuscript, illustrating how codebreaking may assist historical research both to reconstruct the content of encrypted letters and to identify anonymous cipher tables.
Analysing Inconsistencies and Errors in PoS Tagging in two Icelandic Gold Standards
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 287--291, 2015) Steingrímsson, Steinþór; Helgadóttir, Sigrún; Rögnvaldsson, Eiríkur; Megyesi, Beáta
Artificial neural network for hoax cryptogram identification
(Tartu University Library, 2024) Foxon, Floe; Waldispühl, Michelle; Megyesi, Beáta
Numerous putative cryptograms remain unsolved. Some, including the Dorabella cryptogram, have been suggestedas hoaxes, i.e., some sort of gibberish with no meaningful underlying plaintext.The statistical properties of a putative cryptogram may be modelled to determine whether the cryptogram groups moreclosely with real or with randomly generated plaintext. Ten thousand plaintexts from an English-language corpus, and ten thousand (pseudo-)randomly generated English-alphabet gibberish texts were studied through their statistical properties, including the alphabet length; the frequency, separation, and entropy of n-grams; the index of coincidence; Zipf’slaw, and mean associated contact counts. An artificial neural network (deep learning) model was fitted to these data, with a cross-validated mean accuracy of 99.8% (standard deviation: 0.1%). This model correctly predicted that arbitrary, out-of-sample simple substitution ciphers represented meaningful English plaintext (as opposed to gibberish) with probabilities close to 1; correctly predicted that arbitrary, out-of-sample gibberish texts were gibberish (as opposed to simple substitution ciphers) with probabilities close to 1; and assigned a probability of meaningful English plaintext of 0.9996 to the Dorabella cryptogram.
Assessing the Performance of Automatic Speech Recognition Systems When Used by Native and Non-Native Speakers of Three Major Languages in Dictation Workflows
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 201--210, 2015) Zapata, Julián; Søeborg Kirkedal, Andreas; Megyesi, Beáta
Automatic conversion of colloquial Finnishto standard Finnish
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 219--223, 2015) Listenmaa, Inari; Tyers, Francis M.; Megyesi, Beáta
Automatic Lemmatisation of Lithuanian MWEs
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 41--49, 2015) Boizou, Loïc; Kovalevskaitė, Jolanta; Rimkutė, Erika; Megyesi, Beáta
Automatic Thematic Classification of the Titles of the Seimas Votes
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 225--231, 2015) Mickevičius, Vytautas; Krilavičius, Tomas; Morkevičius, Vaidas; Mackutė-Varoneckienė, Aušra; Megyesi, Beáta
Automatic word stress annotation of Russian unrestricted text
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 173--180, 2015) Reynolds, Robert; Tyers, Francis; Megyesi, Beáta
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.
Can Artificial Intelligence solve the mysterious anagram from the church of the Poor Clares in Bratislava?
(Tartu University Library, 2024) Antal, Eugen; Zajac, Pavol; Waldispühl, Michelle; Megyesi, Beáta
A mysterious anagram was found in the Church of the Poor Clares in Bratislava, but as far as we know it has never been successfully solved. The anagram contains81 symbols, including specific diphthongsAE, CH, and GY. Unlike other anagramstypical of that age, the symbolsare not ordered alphabetically. We suspectthat a specific order of symbols is relatedto the original order of symbols in theplain text. Even with the suspected orderof letters, the number of possible plain textcandidates is too high to obtain the originaltext with standard methods. We examinealternative scoring methods based onmodern AI text similarity to improve thequality of the candidate plain text candidates.
A case study on supervised classification of Swedish pseudo-coordination
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 11--19, 2015) Ahlberg, Malin; Andersson, Peter; Forsberg, Markus; Tahmasebi, Nina; Megyesi, Beáta
CG-3 — Beyond Classical Constraint Grammar
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 31--39, 2015) Bick, Eckhard; Didriksen, Tino; Megyesi, Beáta
Combining Relational and Distributional Knowledge for Word Sense Disambiguation
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 69--78, 2015) Johansson, Richard; Nieto Piña, Luis; Megyesi, Beáta
The Corpus of American Norwegian Speech (CANS)
(Vilnius, Lithuania, Linköping University Electronic Press, Sweden, pp. 297--300, 2015) Johannessen, Janne Bondi; Megyesi, Beáta
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.
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.