Ruhr-Universität Bochum (RUB): Open Journal Systems
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A New Perspective on Key Switching for BGV-like Schemes
No full textFully homomorphic encryption is a promising approach when computing on encrypted data, especially when sensitive data is involved. For BFV, BGV, and CKKS, three state-of-the-art encryption schemes, the most costly homomorphic primitive is the so-called key switching. While a decent amount of research has been devoted to optimizing other aspects of these schemes, key switching has gone largely untouched. One exception has been a recent work [KLSS23] introducing a new double-decomposition technique. Their contributions are an important addition to the current state-of-the-art with one flaw: They take a limited perspective on key switching parameters and their asymptotic complexity which leads to incorrect conclusions about how effective their approach really is. In our work, we deep dive into key switching and correct, enhance, and improve the current state-of-the-art. We provide a new perspective on key switching parameters for the single- and doubledecomposition techniques, respectively, and show that the former outperforms the latter in most scenarios. Additionally, we revisit an idea by Gentry, Halevi, and Smart [GHS12b] and reduce the number of multiplications
FusionMSM: A Collision-Free and Arithmetic-Optimized FPGA-based Accelerator for Multi-Scalar Multiplication
No full textZero-knowledge Proof (ZKP), is an effective cryptographic primitive that allows one party to verify the correctness of a given statement without disclosing any additional information. It plays a central role in applications such as blockchain transactions and cryptocurrencies. However, implementations of ZKP suffer from the most time-consuming task called Multi-Scalar Multiplication (MSM). Existing works and evaluation criteria primarily emphasize speed enhancement, but overlook optimizations of area overhead. In this paper, a FPGA-based accelerator FusionMSM is designed to reduce the overall latency but also improve area overhead. We attribute the bottleneck of MSM to a three-layer pyramid, including the finite field arithmetic, point operations on elliptic curves and scheduling. For modular arithmetic, we propose an efficient and non-Montgomery modular multiplier by utilizing hybrid multiplication strategy and optimizing multi-bit LUT-based modular reduction. It obtains 1.11 x less area cost and 2.00 x speed-up versus the modular multipliers used in ZKP acceleration works. For point operations, we design a unified and fully pipelined point addition unit, which can run at 500 MHz, the highest frequency in the reported works. On top of that, we present a greedy mechanism to resolve potential collisions, which can reduce the idle cycles of the point addition unit and improve its utilization. As far as we know, FusionMSM achieves the best performance compared to other FPGA-based and ASIC-based works for the input sizes from 218 to 226. For the degree of 220, FusionMSM only needs 12.4% of time in Hardcaml, 24.54% of time in PipeMSM on FPGA, and 36.41% of time in ASIC-based work PipeZK. It also utilizes less resources, resulting in a 90.93% reduction in URAMs, 35.24% reduction in FFs and 47.59% reduction in CARRY8s. Compared to GPU-based implementations, FusionMSM delivers comparable performance but with a lower power of 24.5 W
Kulturspezifika als Schlüssel zur Schaffung der Ambivalenz in Kinderbüchern. Ein Übersetzungsvergleich
Get PDFThis paper examines one of the distinctive features of children’s literature, namely ambivalence or dual readership, in the German children’s book Rico, Oskar und die Tieferschatten (2008) by Andreas Steinhöfel and its Catalan and Spanish translations. The choice of this book is explained by the special role of cultural specifics as the key to creating ambivalence in the source text. On this basis, the hypothesis is put forward here that the success of the target text depends on maintaining ambivalence. To this end, the characteristics of ambivalence in both the source text and the target texts will be explored by means of a qualitative analysis and a corpus-based translation comparison. In order to analyze the ambivalence in the target texts, the translation strategies in the text passages that are significant for the creation of ambivalence are first identified and determined. The starting point for this analysis is the causal relationship between the choice of specific translation strategies and the global translation method. Depending on the intended function of the translation, whether it tends towards the target culture or the source culture, certain strategies are more suitable than others, so that a continuum of translation strategies can be depicted. The opposing poles of this continuum indicate the degree of interventionism and adaptation to the target culture, and vice versa. The ideological implications for the translation and the target culture are drawn from the predominance of a particular translation method
Albert Ventura: Vicenç Riera Llorca. Exili, memòria i classe obrera. Tarragona: Publicacions de la Universitat Rovira i Virgili, 2023
Get PDFSensualitat i episteme en la literatura del barroc. A partir d\u27un poema de Francesc Vicent Garcia (i un de Giambattista Marino i un altre de Francisco de Quevedo)
Get PDFThe following article is a note about the kind of episteme that emerges from the poetry of a more sensual nature written by Francesc Vicent Garcia, Rector of Vallfogona, and, specifically, from the well-known dècima «De la caritat vinguí». The note wants to relate this kind of episteme of Garcia with that of contemporary European authors, in this case, Francisco de Quevedo and Giambattista Marino.The following article is a note about the kind of episteme that emerges from the poetry of a more sensual nature written by Francesc Vicent Garcia, Rector of Vallfogona, and, specifically, from the well-known dècima «De la caritat vinguí». The note wants to relate this kind of episteme of Garcia with that of contemporary European authors, in this case, Francisco de Quevedo and Giambattista Marino
Sustainable, digital, open - Impulses for designing a Moodle-supported OER course in the project Lehrkräfte Plus NRW
Get PDFDer vorliegende Artikel diskutiert das nachhaltige, digitale und offene Design eines Moodle-basierten OER-Kurses und verwendet das Modul „Kommunikation in der Schule" aus dem Projekt „Lehrkräfte Plus NRW“ als Beispiel. Es untersucht dasZusammenspiel von Nachhaltigkeit und Digitalisierung in der Hochschulbildung und betont den wechselseitigen Einfluss dieser beiden Prozesse. Ziel dieses Beitrages ist es, das Bewusstsein für die Vielfalt digitaler Technologien in der Bildung und derenAuswirkungen auf Lehr- und Lernverhalten zu schärfen. Durch die Analyse der Integration von OER im Fremdsprachenunterricht an der Ruhr-Universität Bochum liefert das Papier evidenzbasierte Einblicke und Empfehlungen zur Nutzung digitaler Nachhaltigkeit im Unterricht. Wichtige Aspekte umfassen die Förderung digitaler Kompetenzen, die effiziente Ressourcennutzung und die Ausrichtung an globalen Bildungszielen wie den Nachhaltigkeitszielen der Vereinten Nationen (SDGs). Der Artikel schließt mit praktischen Handlungsempfehlungen zur Erstellung und Verbreitung von OER-Materialien ab, um inklusiven und gerechten Zugang zu hochwertiger Bildung zu fördern.This paper discusses the sustainable, digital, and open design of a Moodle-based OER course, using the module "Kommunikation in der Schule" from the project Lehrkräfte Plus NRW as an example. It explores the intersection of sustainability and digitalizationin higher education, emphasizing the mutual influence of these two processes. The paper aims to enhance awareness of the diversity of digital technologies in education and their impact on teaching and learning behaviors. By examining the integration ofOER in foreign language education at Ruhr University Bochum, the paper provides evidence-based insights and recommendations for leveraging digital sustainability in teaching. Key aspects include the promotion of digital competencies, efficient resourceuse, and the alignment with global educational goals like the UN\u27s Sustainable Development Goals (SDGs). The paper concludes with practical recommendations and guidelines for creating and sharing OER materials, aiming to foster inclusive and equitable access to quality education
Students in dialogue with AI : Does automated feedback on writing promote learning and motivation?
Get PDFDer Beitrag untersucht im Rahmen der eigenen Unterrichtsforschung den Einsatz von KI und KI-Feedback im hochschulischen Fremdsprachenunterricht. In einer Trendstudie wurden über drei Semester hinweg knapp 200 Studierende an den Universitäten Bochum, München und Münster online zu ihren digitalen Kompetenzen, ihrer Nutzung von KI-Tools sowie ihren Präferenzen bei Feedbackquellen (Lehrkraft, Mitstudierende, KI) befragt. Die Ergebnisse zeigen, dass die Mehrheit der Befragten über solide digitale Kompetenzen verfügt und regelmäßig KI-Tools nutzt. Zwar gelten Lehrkräfte nach wie vor als wichtigste Feedbackquelle, doch KI wird zunehmend als Ergänzung wahrgenommen. Gleichzeitig erfolgt der Erwerb von KI-Kompetenzen jedoch meist im Selbststudium. Der Beitrag verdeutlicht das Potenzial von KI-Feedback im Fremdsprachenunterricht, unterstreicht aber die Notwendigkeit einer didaktisch reflektierten Einbettung und gezielten Förderung kritischer KI-Kompetenzen bei Studierenden.This article examines the use of AI and AI-generated feedback in foreign language teaching at university level as part of our teaching research. In a trend study conducted over three semesters, nearly 200 students at the universities of Bochum, Munich, and Münster were surveyed online about their digital skills, use of AI tools, and preferred sources of feedback (teachers, fellow students, AI). The results show that most respondents have sound digital skills and regularly use AI tools. Although teachers are still considered the most important source of feedback, AI is increasingly viewed as a complement. AI skills, however, are mostly acquired through self-study. This article highlights the potential of AI-generated feedback in foreign language teaching, but emphasises the need for its didactic integration and the specific development of critical AI skills among students
Cursing Beyond the Grave: Imprecations and Jewish Funerary Culture in Antiquity
Get PDFThis article discusses curses found in ancient and late antique Jewish funerary inscriptions. It begins with a typology of imprecatory texts based on a survey of funerary epigraphy, both Jewish and non-Jewish. It proceeds with an analysis of explicit curse formulae found in a Jewish funerary context: on ossuaries, on the walls of burial caves, or on architectural elements of graves. The article discusses several aspects of these curses, placing them in a physical, religious, and psychological context
Building PRFs from TPRPs: Beyond the Block and the Tweak Length Bounds
No full textA secure n-bit tweakable block cipher (TBC) using t-bit tweaks can be modeled as a tweakable uniform random permutation, where each tweak defines an independent random n-bit permutation. When an input to this tweakable permutation is fixed, it can be viewed as a perfectly secure t-bit random function. On the other hand, when a tweak is fixed, it can be viewed as a perfectly secure n-bit random permutation, and it is well known that the sum of two random permutations is pseudorandom up to 2n queries.A natural question is whether one can construct a pseudorandom function (PRF) beyond the block and the tweak length bounds using a small number of calls to the underlying tweakable permutations. A straightforward way of constructing a PRF from tweakable permutations is to xor the outputs from two tweakable permutations with c bits of the input to each permutation fixed. Using the multi-user security of the sum of two permutations, one can prove that the (t + n − c)-to-n bit PRF is secure up to 2n+c queries.In this paper, we propose a family of PRF constructions based on tweakable permutations, dubbed XoTPc, achieving stronger security than the straightforward construction. XoTPc is parameterized by c, giving a (t + n − c)-to-n bit PRF. When t < 3n and c = t/3 , XoTPt/3 becomes an (n + 2t/3 )-to-n bit pseudorandom function, which is secure up to 2n+2t/3 queries. It provides security beyond the block and the tweak length bounds, making two calls to the underlying tweakable permutations. In order to prove the security of XoTPc, we extend Mirror theory to q ≫ 2n, where q is the number of equations. From a practical point of view, our construction can be used to construct TBC-based MAC finalization functions and CTR-type encryption modes with stronger provable security compared to existing schemes