Ruhr-Universität Bochum (RUB): Open Journal Systems
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OPTIMSM: FPGA hardware accelerator for Zero-Knowledge MSM
Get PDFThe Multi-Scalar Multiplication (MSM) is the main barrier to accelerating Zero-Knowledge applications. In recent years, hardware acceleration of this algorithm on both FPGA and GPU has become a popular research topic and the subject of a multi-million dollar prize competition (ZPrize). This work presents OPTIMSM: Optimized Processing Through Iterative Multi-Scalar Multiplication. This novel accelerator focuses on the acceleration of the MSM algorithm for any Elliptic Curve (EC) by improving upon the Pippenger algorithm. A new iteration technique is introduced to decouple the required buckets from the window size, resulting in fewer EC computations for the same on-chip memory resources. Furthermore, we combine known optimizations from the literature for the first time to achieve additional latency improvements. Our enhanced MSM implementation significantly reduces computation time, achieving a speedup of up to x12.77 compared to recent FPGA implementations. Specifically, for the BLS12-381 curve, we reduce the computation time for an MSM of size 224 to 914 ms using a single compute unit on the U55C FPGA or to 231 ms using four U55C devices. These results indicate a substantial improvement in efficiency, paving the way for more scalable and efficient Zero-Knowledge proof systems
Constant time lattice reduction in dimension 4 with application to SQIsign
Get PDFIn this paper we propose a constant time lattice reduction algorithm for integral dimension-4 lattices. Motivated by its application in the SQIsign postquantum signature scheme, we provide for the first time a constant time LLLlike algorithm with guarantees on the length of the shortest output vector. We implemented our algorithm and ensured through various tools that it indeed operates in constant time. Our experiments suggest that in practice our implementation outputs a Minkowski reduced basis and thus can replace a non constant time lattice reduction subroutine in SQIsign
On the Average Random Probing Model
Get PDFMasking is one of the main countermeasures against side-channel analysis since it relies on provable security. In this context, “provable” means that a security bound can be exhibited for the masked implementation through a theoretical analysis in a given threat model. The main goal in this line of research is therefore to provide the tightest security bound, in the most realistic model, in the most generic way. Yet, all of these objectives cannot be reached together. That is why the masking literature has introduced a large spectrum of threat models and reductions between them, depending on the desired trade-off with respect to these three goals. In this paper, we focus on three threat models, namely the noisy-leakage model (realistic yet hard to work with), the random probing (unrealistic yet easy to work with), and more particularly a third intermediate model called average random probing. Average random probing has been introduced by Dziembowski et al. at Eurocrypt 2015, in order to exhibit a tight reduction between noisy-leakage and random probing models, recently proven by Brian et al. at Eurocrypt 2024. This milestone has strong practical consequences, since otherwise the reduction from the noisy leakage model to the random probing model introduces a prohibitively high constant factor in the security bound, preventing security evaluators to use it in practice. However, we exhibit a gap between the average random probing definitions of Dziembowski et al. (denoted hereafter by DFS-ARP) and Brian et al. (simply denoted by ARP). Whereas any noisy leakage can be tightly reduced to DFS-ARP, we show in this paper that it cannot be tightly reduced to ARP, unless requiring extra assumptions, e.g., if the noisy leakage is deterministic. Our proof techniques do not involve more tools than the one used so far in such reductions, namely basic probability facts, and known properties of the total variation distance. As a consequence, the reduction from the noisy leakage to the random probing — without high constant factor — remains unproven. This stresses the need to clarify the practical relevance of analyzing the security of masking in the random probing model since most of the current efforts towards improving the constructions and their security proofs in the random probing model might be hindered by potentially unavoidable loss in the reduction from more realistic but currently less investigated leakage models
Cymric: Short-tailed but Mighty: Beyond-birthday-bound Secure Authenticated Encryption for Short Inputs
Get PDFAuthenticated encryption (AE) is a fundamental tool in today’s secure communication. Numerous designs have been proposed, including well-known standards such as GCM. While their performance for long inputs is excellent, that for short inputs is often problematic due to high overhead in computation, showing a gap between the real need for IoT-like protocols where packets are often very short. Existing dedicated short-input AEs are very scarce, the classical Encode-then-encipher (Bellare and Rogaway, Asiacrypt 2000) and Manx (Adomnicăi et al., CT-RSA 2023), using up to two block cipher calls. They have superior performance for (very) short inputs, however, security is up to n/2 bits, where n is the block size of the underlying block cipher. This paper proposes a new family of short-input AEs, dubbed Cymric, which ensure beyond-birthday-bound (BBB) security. It supports a wider range of input space than EtE and Manx with the help of one additional block cipher call (thus three calls). In terms of the number of block cipher calls, Cymric is the known minimum construction of BBB-secure AEs, and we also prove this is indeed minimal by presenting an impossibility result on BBB-secure AE with two calls. Finally, we show a comprehensive benchmark on microcontrollers to show performance advantage over existing schemes
HIPR: Hardware IP Protection through Low-Overhead Fine-Grain Redaction
Get PDFHardware intellectual property (IP) blocks have been subjected to various forms of confidentiality and integrity attacks in recent years due to the globalization of the semiconductor industry. System-on-chip (SoC) designers are now considering a zero-trust model for security, where an IP can be attacked at any stage of the manufacturing process for piracy, cloning, overproduction, or malicious alterations. Hardware redaction has emerged as a promising countermeasure to thwart confidentiality and integrity attacks by untrusted entities in the globally distributed supply chain. However, existing redaction techniques provide this security at high overhead costs, making them unsuitable for real-world implementation. In this paper, we propose HIPR, a fine-grain redaction methodology that is robust, scalable, and incurs significantly lower overhead compared to existing redaction techniques. HIPR redacts security-critical Boolean and sequential logic from the hardware design, performs interconnect randomization, and employs multiple overhead optimization steps to reduce overhead costs. We evaluate HIPR on open-source benchmarks and reduce area overheads by 1 to 2 orders of magnitude compared to state-of-the-art redaction techniques without compromising security. We also demonstrate that the redaction performed by HIPR is resilient against conventional functional and structural attacks on hardware IPs. The redacted test IPs used to evaluate HIPR are available at: https://github.com/UF-Nelms-IoT-Git-Projects/HIPR
“You simply make use of the advantages of the different media”: Reasoning patterns for designing literacy teaching with digital media from the perspective of actors in further training for teachers
Get PDFUm Lehrkräfte kontinuierlich hinsichtlich neuer gesellschaftlicher und pädagogischer Herausforderungen zu professionalisieren, ist die dritte Phase der Lehrkräftebildung entscheidend. Eine dieser aktuellen Herausforderungen stellt die digitale Transformation der Gesellschaft und des Bildungssystem dar. Für die sprachliche Bildung bedeutet das: Digitale Medien können als Lernmittel einerseits das sprachliche Lernen verbessern, andererseits müssen veränderte sprachliche Praktiken in digitalen Kontexten zum Lerngegenstand gemacht werden, um bspw. Kompetenzen im digitalen Lesen bei Lernenden auszubilden. Die vorliegende Arbeit untersucht dazu die Perspektiven auf digitalitätsbezogene Sprachbildung von Verbundkoordinator:innen im BiSS-Transfer-Projekt, die als zentrale Akteur:innen der Lehrkräftefortbildung die Unterrichtsgestaltung von Lehrkräften durch ihre Arbeit beeinflussen können. Um ihre Vorstellungen von der Gestaltung sprachbildenden Unterrichts mit digitalen Medien besser zu verstehen, rekonstruiert die vorliegende Interviewstudie zugrundeliegende Begründungsmuster der Verbundkoordinator:innen unter Verwendung von Prinzipien der Grounded Theory. Die Ergebnisse zeigen, dass der Einsatz digitaler Medien hinsichtlich eines wahrgenommenen Mehrwerts gegenüber analogen Medien abgewogen wird. Dabei findet eine Orientierung an Unterrichtszielen im Paradigma der Literalität statt, das auf das Buch als Leitmedium fokussiert ist. Um die Herausforderungen der Digitalität in der sprachlichen Bildung umfassend zu berücksichtigen, sind neue Zielorientierungen in der Lehrkräftebildung erforderlich, die digitale Kompetenzen stärker integrieren und die Lehr- und Lernkultur nachhaltig transformieren.Further training for teachers (in Germany called the „third phase of teacher training“) is critical to the ongoing professionalization of teachers to meet new societal and pedagogical challenges. One of these current challenges is the digital transformation of society and education. For literacy education, this means that on the one hand, digital media as a learning tool can enhance language learning, while on the other hand, changing linguistic practices in digital contexts need to be made the subject of learning, for example, to develop digital reading skills in learners. This study examines the perspectives on teaching literacy with digital media of network coordinators in the BiSS-Transfer project (Transfer of Language Education, Reading and Writing Support). These coordinators are central actors in teacher training, who influence how teachers design their lessons. To better understand their ideas about designing literacy teaching with digital media, this interview study uses Grounded Theory principles to reconstruct the underlying reasoning patterns of the network coordinators. The results show that the use of digital media is weighed up against analogue media in terms of perceived added value. This is orientated towards teaching objectives in the paradigm of literacy, which focuses on the book as the main medium. In order to fully address the challenges of digitization in language education, new objectives are needed in teacher training that integrate digital literacies more fully and change the culture of teaching and learning in the long term
The “Treasure of Como” and the Production of Solidi During the Late Roman Empire
Get PDFThe Como Treasure, discovered in 2018 during archaeological excavations in the Roman town of Novum Comum, consists of 1,000 solidi and a few other gold artifacts – three rings, a small piece of an ingot and incomplete and unfinished gold jewelry. It is the most important hoard of Roman gold coins discovered in Central/Western Europe in recent decades. The examination of the solidi allowed for the study of the traces of workmanship and the reconstruction of the operative chain used in Late Antiquity mints. The gold was melted under oxidizing conditions, purified by cupellation and cementation and then assayed. In order to obtain the blanks, foils were made, cut in round plates with iron shears. Then the edges and the weight were adjusted al pezzo with iron files. As some of the impurities visible to the naked eye show on some coins, iron filings from files accidentally got into the filings or gold waste used for melting. Coins were obtained by minting using dies engraved according to a well determined sequence: after a subdivision of the die’s surface with compasses, the figures and finally the inscriptions were engraved. The production process was concluded by checking the weight of the coins. In times of intensive production mints could shorten their production times by recoining old coins. In this case, the purity of the gold was checked by taking a sample from the center of the coins before their recoinage. These different stages required specialized staff and ateliers with different features placed in a building that guaranteed high levels of security and that was well connected to the road network to allow supplies. These characteristics seem to be found in a building unearthed in old excavations in Milan and already interpreted as a bath. On the basis of the information currently available, however, the possibility of it being the mint of the comitatus cannot be ruled out
Neuroethics and agency: Some comments on Joshua May’s Neuroethics
Get PDFNeuroethics provides a sober and thoughtful introduction to major issues in neuroethics. This discussion offers a measured assessment and critique of the book
Review: Römhild, Ricardo (2024): Global Citizenship Education im Fremdsprachenunterricht.
No full textRezension: Römhild, Ricardo (2024): Global Citizenship Education im Fremdsprachenunterricht. Review: Römhild, Ricardo (2024): Global Citizenship Education im Fremdsprachenunterricht.