16 research outputs found

    Improved Linear Approximations to ARX Ciphers and Attacks Against ChaCha

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    In this paper, we present a new technique which can be used to find better linear approximations in ARX ciphers. Using this technique, we present the first explicitly derived linear approximations for 3 and 4 rounds of ChaCha and, as a consequence, it enables us to improve the recent attacks against ChaCha. Additionally, we present new differentials for 3 and 3.5 rounds of ChaCha that, when combined with the proposed technique, lead to further improvement in the complexity of the Differential-Linear attacks against ChaCha

    BAKSHEESH: Similar Yet Different From GIFT

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    We propose a lightweight block cipher named BAKSHEESH, which follows up on the popular cipher GIFT-128 (CHES\u2717). BAKSHEESH runs for 35 rounds, which is 12.50 percent smaller compared to GIFT-128 (runs for 40 rounds) while maintaining the same security claims against the classical attacks. The crux of BAKSHEESH is to use a 4-bit SBox that has a non-trivial Linear Structure (LS). An SBox with one or more non-trivial LS has not been used in a cipher construction until DEFAULT (Asiacrypt\u2721). DEFAULT is pitched to have inherent protection against the Differential Fault Attack (DFA), thanks to its SBox having 3 non-trivial LS. BAKSHEESH, however, uses an SBox with only 1 non-trivial LS; and is a traditional cipher just like GIFT-128, with no claims against DFA. The SBox requires a low number of AND gates, making BAKSHEESH suitable for side channel countermeasures (when compared to GIFT-128) and other niche applications. Indeed, our study on the cost of the threshold implementation shows that BAKSHEESH offers a few-fold advantage over other lightweight ciphers. The design is not much deviated from its predecessor (GIFT-128), thereby allowing for easy implementation (such as fix-slicing in software). However, BAKSHEESH opts for the full-round key XOR, compared to the half-round key XOR in GIFT. Thus, when taking everything into account, we show how a cipher construction can benefit from the unique vantage point of using 1 LS SBox, by combining the state-of-the-art progress in classical cryptanalysis and protection against device-dependent attacks. We, therefore, create a new paradigm of lightweight ciphers, by adequate deliberation on the design choice, and solidify it with appropriate security analysis and ample implementation/benchmark

    Tehnike minimalne obrade za proizvodnju i čuvanje hrane prilagođene individualnim potrebama

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    Tailor-made foods, also known as foods with programmable properties, are specialised systems with unique composition prepared by different methods, using the known mechanisms of action of their bioactive ingredients. The development of tailor-made foods involves the evaluation of individual components, including bioactive substances derived from waste products of other productions, such as essential oils. These components are evaluated both individually and in combination within food compositions to achieve specific functionalities. This review focuses on the application of minimal processing technologies for the production and preservation of tailor-made foods. It examines a range of approaches, including traditional and emerging technologies, as well as novel ingredients such as biomolecules from various sources and microorganisms. These approaches are combined according to the principles of hurdle technology to achieve effective synergistic effects that enhance food safety and extend the shelf life of tailor-made foods, while maintaining their functional properties. §Paper was presented at the 11th Central European Congress on Food and Nutrition CEFood2022, Čatež ob Savi, Slovenia, 27-30 September 2022Hrana prilagođena individualnim potrebama, poznata i kao hrana s prilagođenim svojstvima, je posebno pripremljena hrana jedinstvenog sastava, dobivena različitim metodama koje se zasnivaju na dobro poznatim mehanizmima djelovanja biološki aktivnih sastojaka. Razvoj takve hrane obuhvaća procjenu pojedinih sastojaka, uključujući biološki aktivnih spojeva izoliranih iz otpada nastalog u proizvodnji, poput eteričnih ulja. Ti su spojevi ispitani pojedinačno i u kombinaciji sa sastojcima hrane, u svrhu razvoja određenih funkcionalnih svojstava. U fokusu ovog revijalnog prikaza je primjena tehnika minimalne obrade za proizvodnju i čuvanje hrane prilagođene jedinstvenim potrebama. Razmotreni su različiti pristupi, uključujući tradicionalne i nove tehnologije, te novi sastojci, poput biomolekula što potječu iz različitih izvora i mikroorganizama. Ti su pristupi kombinirani na principu tehnologije preprekama, za uspješno postizanje sinergijskog učinka koji poboljšava sigurnost i produljuje vrijeme skladištenja hrane, dok istovremeno zadržava njezina funkcionalna svojstva

    Lyra: Password-Based Key Derivation with Tunable Memory and Processing Costs

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    We present Lyra, a password-based key derivation scheme based on cryptographic sponges. Lyra was designed to be strictly sequential (i.e., not easily parallelizable), providing strong security even against attackers that use multiple processing cores (e.g., custom hardware or a powerful GPU). At the same time, it is very simple to implement in software and allows legitimate users to fine-tune its memory and processing costs according to the desired level of security against brute force password guessing. We compare Lyra with similar-purpose state-of-the-art solutions, showing how our proposal provides a higher security level and overcomes limitations of existing schemes. Specfically, we show that if we fix Lyra\u27s total processing time t in a legitimate platform, the cost of a memory-free attack against the algorithm is exponential, while the best known result in the literature (namely, against the scrypt algorithm) is quadratic. In addition, for an identical same processing time, Lyra allows for a higher memory usage than its counterparts, further increasing the cost of brute force attacks

    Методи побудови та дослідження властивостей малоресурсних блокових шифрів та їх компонентів

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    Дисертація присвячена розробці та удосконаленню методів аналізу криптографічних властивостей компонентів симетричних блокових шифрів та побудові перспективних криптографічних перетворень. Метою дисертаційної роботи є підвищення продуктивності симетричних криптографічних перетворень і удосконалення методів аналізу їх стійкості.Rodinko M. Yu. Methods of construction and research of properties of lightweight block ciphers and their components. – Qualification scholarly paper: a manuscript. Thesis submitted for obtaining the Doctor of Philosophy degree in Information Technologies, Speciality 122 – Computer Science. – V. N. Karazin Kharkiv National University, Ministry of Education and Science of Ukraine, Kharkiv, 2020. The dissertation is devoted to the development and improvement of methods on cryptographic properties analysis of block ciphers components and construction of perspective cryptographic transformations. The aim of the dissertation is to increase performance of symmetric cryptographic transformations and improve methods of analysis of their strength

    Thinking with the Global South and Decolonizing Indigeneity: Indigenous and Peasant Struggles to Reclaim Spaces, Identities, and Futures in Cauca, Colombia

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    In this dissertation, I examine indigenous and rural identities and economic practices in Cauca, Colombia that are illustrative of Southern efforts to destabilize Western and European hegemonic histories, and reassert the plural worldviews and practices that persist to this day. The indigenous and peasant movements that I highlight problematize coloniality’s totalizing and universalizing tendencies to erase local specificity across the post-colonial world. I argue these efforts are collectively decolonial in their orientations, as they seek to decenter the centrality of Western experiences in favor of the plurality of worldviews that are thriving in the Global South. Employing ethnographic methods, I find that decolonizing indigenous post-secondary education forges unity across ethnic difference, celebrating the plurality of ways of relating to the world that exist among Cauca’s indigenous peoples today. Further, I argue that indigenous post-secondary education is better conceived of as a pluriversity that opens its classrooms and students to the world around them, yet is emplaced in the specific realities of each community. Decolonial struggles to reclaim and assert rural peasant economic identities in Cauca attempt to transcend colonial ethnic identities. These overlapping social movements are creating a space for peasant identities and economic practices that seek to ‘make aware’, ‘make visible’, and ‘dignify’ peasant economics by publicly asserting their ‘value’ as peasants. Finally, I find that interrelationships between Nature and economies have been undertheorized to primarily focus on Western capitalism as the driving force in creating nature. I develop the notion of a harmonious economy (economía armónica) to theorize how indigenous relationships to Mother Earth engender qualitatively different economies in Cauca. Taken together, these diverging and intersecting movements suggest that productive work can be done at the intersections of political ecology, diverse economies, and indigenous geographies in order to understand the wealth of decolonial efforts in Colombia’s Andean Highlands

    The Design and Analysis of Symmetric Cryptosystems

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    Lyra2: Efficient Password Hashing with High Security against Time-Memory Trade-Offs

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    We present Lyra2, a password hashing scheme (PHS) based on cryptographic sponges. Lyra2 was designed to be strictly sequential (i.e., not easily parallelizable), providing strong security even against attackers that uses multiple processing cores (e.g., custom hardware or a powerful GPU). At the same time, it is very simple to implement in software and allows legitimate users to fine tune its memory and processing costs according to the desired level of security against brute force password-guessing. Lyra2 is an improvement of the recently proposed Lyra algorithm, providing an even higher security level against different attack venues and overcoming some limitations of this and other existing schemes

    The Legitimisation of Peace Negotiations: A Role for Civil Society?

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    Questioning a theoretical jump made in current literature from civil society participation in ne-gotiations to legitimacy in order to explain the impact on peace sustainability, the thesis seeks to unpack the very concept of legitimacy. The work considers the question of how peace nego-tiations are made more legitimate through the inclusion of civil society in an empirically and methodologically abductive manner. This entails both the answering of what the constitutive components of a legitimisation process are and why they may be occurring. On the basis of a heuristic model for legitimate peace negotiations, drawn from contemporary theories on legiti-macy, two case studies are considered: the Liberian peace negotiations in 2003 and the Kenyan National Dialogue and Reconciliation in 2008. Using rich empirical data from over 100 interviews and 12 focus groups with market women, teachers and youth, collected during extensive fieldwork in Liberia and Kenya, an especially adapted form of comprehensive process-tracing is applied to the case studies. Applying the method of comprehensive process-tracing, permitting both a constitutive and a causal analysis, the components that together constitute the legitimisation process are singled out. In addition, the reasons why these come to be are traced causally. The biggest finding is that civil society is not exclusively responsible for ensuring the legitimisation of peace negotiations. Other so-called guarantors of legitimacy also play a role – including international mediators - in addition to in-dividualised form of participation for the conflict-affected population. On the basis of the empir-ical analysis, a theory of legitimate peace negotiations is developed. According to this, a legitimisation process is made up of outcome and participation-based characteristics, where civil society actors play a crucial but not exclusive role. Moreover, the legitimisation takes place simultaneously at the negotiations and in a public arena. The research has repercussions for the debates on civil society, representation, local ownership and emancipatory peacebuilding

    The Music Sound

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    A guide for music: compositions, events, forms, genres, groups, history, industry, instruments, language, live music, musicians, songs, musicology, techniques, terminology , theory, music video. Music is a human activity which involves structured and audible sounds, which is used for artistic or aesthetic, entertainment, or ceremonial purposes. The traditional or classical European aspects of music often listed are those elements given primacy in European-influenced classical music: melody, harmony, rhythm, tone color/timbre, and form. A more comprehensive list is given by stating the aspects of sound: pitch, timbre, loudness, and duration. Common terms used to discuss particular pieces include melody, which is a succession of notes heard as some sort of unit; chord, which is a simultaneity of notes heard as some sort of unit; chord progression, which is a succession of chords (simultaneity succession); harmony, which is the relationship between two or more pitches; counterpoint, which is the simultaneity and organization of different melodies; and rhythm, which is the organization of the durational aspects of music
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