95 research outputs found

    The Russian Fish with Caviar

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    Abstract: Historians have noted that the capture of the "Russian Fish" from the Germans was probably the most important outcome of the 1945 TICOM operation. Recently declassified documents have now provided a wealth of information pertaining to this vital break into Soviet communications at the dawn of the Cold War

    Manuscrito de Voynich - Análisis del algoritmo de codificación con los métodos de cifrado conocidos en la época medieval y resultados de las marginalias que no fueron encriptadas

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    In the present study I describe and analyze two objectives, the first is about opposition and equivalence of the Voynich manuscript coding algorithm with the known in medieval period methods of ciphering. According to the results of my innovative research of the Voynich manuscript was written in medieval Galician (Galician-Portuguese). Its coding algorithm was influenced by the substitution cipher of using a polyalphabetic cipher for the most part of its text, as well as it was definitely influenced by transposition cipher for double ciphered alchemical text. However, it should be mentioned that there are significant differences between the codes that were used in the medieval period and the encoded algorithm of the Voynich manuscript. For the reason that made deciphering more complicated over the centuries, substitution encryption of a polyalphabetic cipher was used partly and simultaneusly with monoalphabetic cipher in addition to uncoded text at all. Therefore the main thing to take into consideration is that the second objective of the most interest in this particular article are parts of the Voynich manuscript texts – marginalies– that were not encrypted at all and their reading.En el presente estudio describo y analizo dos objetivos, el primero es sobre la oposición y la equivalencia del algoritmo de codificación del manuscrito Voynich con los métodos conocidos de cifrado del período medieval. Según los resultados de mi investigación innovadora del manuscrito Voynich, este fue escrito en gallego medieval (gallego-portugués). Su algoritmo de codificación fue influenciado por el cifrado de sustitución del uso de un cifrado polialfabético para la mayor parte de su texto, así como definitivamente fue influenciado por el cifrado de transposición para texto alquímico de cifrado doble. Sin embargo, debe mencionarse que existen diferencias significativas entre los códigos que se usaron en el período medieval y el algoritmo codificado del manuscrito Voynich. Por la razón que hizo que el descifrado fuera más complicado a lo largo de los siglos, el cifrado por sustitución de un cifrado polialfabético se usó en parte y simultáneamente con cifrado monoalfabético, además del texto sin codificar. Por lo tanto, lo principal a tener en cuenta es que el segundo objetivo de mayor interés en este artículo en particular son partes de los textos del manuscrito de Voynich –marginalias– que no se cifraron en absoluto y su lectura

    The Role of Female Cryptanalysts from 1914 to 1946

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    This thesis shows that the history of cryptanalysis in Britain in the first half of the twentieth century has focussed on the contribution of men to the virtual exclusion of that of women, and produces evidence to prove that, from the First World War onwards, women, although in a minority, were working at the same level as their male counterparts, despite their lack of mention in the published literature which generally holds that only men worked as cryptanalysts during this period. The present research identifies that this was not the case, and that though the number of confirmed female cryptanalysts remains small and elusive, these women were nonetheless important for the role that they played. This thesis examines published work on British cryptanalysis between 1914 and 1946, demonstrating that these accounts are almost exclusively by men and about men. The research presented uses original documentation and interviews to advance and place on record knowledge about female cryptanalysts who worked in high-level codebreaking during time both of war and peace in a gendered approach. The analysis sets out the case studies of six women - four cryptanalysts, one linguist and a decoder - who typify the roles that women held in cryptanalysis between 1914 and 1946, providing an in-depth study of their backgrounds and roles they carried out for the British Admiralty’s Room 40, the War Office’s MI1(b) and HushWAACs, and the Foreign Office’s Government Code and Cypher School (GC&CS). The thesis provides a detailed historiographical chronology in a gendered approach of the women’s role in cryptanalysis from the beginnings of modern codebreaking in the First World War, through the interwar creation of GC&CS, to the vast cryptanalytical organisation at Bletchley Park during the Second World War, setting out the context of relevant literature and archival materials. Definitions are derived for key terms whose meanings have changed over the period, causing confusion and erroneous conclusions to be drawn, and key themes are identified which can be used in the identification of future female cryptanalysts. This thesis clearly identifies that women were working as high-grade cryptanalysts during the period 1914 to 1946, and offers pointers and analytical tools to potential further identifications in future research

    The Rubik\u27s Crypto-Cube: a Trans-Composite Cipher

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    Cryptography, the art or science of writing messages in code to disguise the content, has been a source of interest for millenia. Those who exchange secret messages do so through the medium of a cryptosystem, a single set of devices used in order to encrypt plaintext and decrypt ciphertext. This is a study of the Rubik\u27s Cube as a trans-composite cipher

    Kickshaws

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    Readers are encouraged to send their own favorite linguistic kickshaws to the Associate Editor. All answers appear in the Answers and Solutions at the end of this issue

    A Modified Vigenère Cipher based on Time and Biometrics features

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    Biometrics is widely used with security systems nowadays; each biometric modality can be useful and has distinctive properties that provide uniqueness and ambiguity for security systems especially in communication and network technologies. This paper is about using biometric features of fingerprint, which is called (minutiae) to cipher a text message and ensure safe arrival of data at receiver end. The classical cryptosystems (Caesar, Vigenère, etc.) became obsolete methods for encryption because of the high-performance machines which focusing on repetition of the key in their attacks to break the cipher. Several Researchers of cryptography give efforts to modify and develop Vigenère cipher by enhancing its weaknesses. The proposed method uses local feature of fingerprint represented by minutiae positions to overcome the problem of repeated key to perform encryption and decryption of a text message, where, the message will be ciphered by a modified Vigenère method. Unlike the old usual method, the key constructed from fingerprint minutiae depend on instantaneous date and time of ciphertext generation. The Vigenère table consist of 95 elements: case sensitive letters, numbers, symbols and punctuation.  The simulation results (with MATLAB 2021b) show that the original message cannot be reconstructed without the presence of the key which is a function of the date and time of generation. Where 720 different keys can be generated per day which mean 1440 distinct ciphertexts can be obtained for the same message daily

    Practical free-start collision attacks on 76-step SHA-1

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    In this paper we analyze the security of the compression function of SHA-1 against collision attacks, or equivalently free-start collisions on the hash function. While a lot of work has been dedicated to the analysis of SHA-1 in the past decade, this is the first time that free-start collisions have been considered for this function. We exploit the additional freedom provided by this model by using a new start-from-the-middle approach in combination with improvements on the cryptanalysis tools that have been developed for SHA-1 in the recent years. This results in particular in better differential paths than the ones used for hash function collisions so far. Overall, our attack requires about 2502^{50} evaluations of the compression function in order to compute a one-block free-start collision for a 76-step reduced version, which is so far the highest number of steps reached for a collision on the SHA-1 compression function. We have developed an efficient GPU framework for the highly branching code typical of a cryptanalytic collision attack and used it in an optimized implementation of our attack on recent GTX 970 GPUs. We report that a single cheap US\$ 350 GTX 970 is sufficient to find the collision in less than 5 days. This showcases how recent mainstream GPUs seem to be a good platform for expensive and even highly-branching cryptanalysis computations. Finally, our work should be taken as a reminder that cryptanalysis on SHA-1 continues to improve. This is yet another proof that the industry should quickly move away from using this function
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