Ruhr-Universität Bochum (RUB): Open Journal Systems
Not a member yet
4280 research outputs found
Sort by
FINAL bootstrap acceleration on FPGA using DSP-free constant-multiplier NTTs
Get PDFThis work showcases Quatorze-bis, a state-of-the-art Number Theoretic Transform circuit for TFHE-like cryptosystems on FPGAs. It contains a novel modular multiplication design for modular multiplication with a constant for a constant modulus. This modular multiplication design does not require any DSP units or any dedicated multiplier unit, nor does it require extra logic when compared to the state-of-the-art modular multipliers. Furthermore, we present an implementation of a constant multiplier Number Theoretic Transform design for TFHE-like schemes. Lastly, we use this Number Theoretic Transform design to implement a FINAL hardware accelerator for the AMD Alveo U55c which improves the Throughput metric of TFHE-like cryptosystems on FPGAs by a factor 9.28x over Li et al.’s NFP CHES 2024 accelerator and by 10-25% over the absolute state-of-the-art design FPT [vBDTV23] while using one third of FPTs DSPs
Secure and efficient transciphering for FHE-based MPC
Get PDFTransciphering (or Hybrid-Homomorphic Encryption, HHE) is an established technique for avoiding ciphertext expansion in HE applications, saving communication and storage resources. Recently, it has also been shown to be a fundamental component in the practical construction of HE-based multi-party computation (MPC) protocols, being used both for input data and intermediary results (Smart, IMACC 2023). In these protocols, however, ciphers are used with keys that are jointly generated by multiple (possibly malicious) parties, which may require additional security assumptions that have been so far overlooked in the HHE literature. In this paper, we formalize this issue as a security against related-key attacks (RKA) problem and provide efficient solutions for it. We start by presenting an efficient method for homomorphically evaluating Mixed-Filter-Permutator (MFP) ciphers in leveled mode, enabling speedups of up to thousands of times compared to previous literature. For the multi-party scenario, we focus specifically on the Margrethe cipher (Hoffmann et al., INDOCRYPT 2023). We show that, contrary to other commonly used HHE ciphers (e.g. FLIP), Margrethe is out-of-the-box secure for any protocols that allow malicious parties to learn up to two related key streams, enabling security for the vast majority of static MPC protocols. For other cases, we quantify the loss of security based on the number of related key streams (which often depends on the number of malicious parties and specific protocol). Performance-wise, our implementation of Margrethe takes just 3.9 ms to transcipher 4-bit messages, being significantly faster than the state of the art in terms of latency
Review: Joachim Schlabach / Constanze Bradlaw / Britta Hufeisen (Hrsg.) (2024): Mehrsprachenlernen in gesellschaftlichen und institutionellen Kontexten. Deutsch als Fremd- und Zweitsprache im Fokus der Mehrsprachendebatte.
No full textRezension: Joachim Schlabach / Constanze Bradlaw / Britta Hufeisen (Hrsg.) (2024): Mehrsprachenlernen in gesellschaftlichen und institutionellen Kontexten. Deutsch als Fremd- und Zweitsprache im Fokus der Mehrsprachendebatte.Review: Joachim Schlabach / Constanze Bradlaw / Britta Hufeisen (Hrsg.) (2024): Mehrsprachenlernen in gesellschaftlichen und institutionellen Kontexten. Deutsch als Fremd- und Zweitsprache im Fokus der Mehrsprachendebatte
New General MDS Matrix Construction Method Towards Low Area
No full textMaximum Distance Separable (MDS) matrices have been widely used in symmetric cryptographic primitives because of their excellent cryptographic properties. However, due to the heavy area cost, larger-scale MDS matrices than 4 x 4 ones are limited in ciphers, although they have a larger branch number. In this paper, we propose a general method for constructing MDS matrices with low implementation area cost, using matrix decomposition, automatic search, and symbolic computation techniques. According to matrix decomposition theory, every invertible matrix can be decomposed into a sequence of elementary matrices, including Type-1 (row switching), Type-2 (row multiplication) and Type-3 (row addition) elementary matrices. So, we first propose a greedy algorithm to construct MDS matrix patterns with as few Type-3 elementary matrices as possible. Then, we build an automatic search model to minimize the implementation area of multiplication coefficients used in Type-3 elementary matrices. Lastly, another greedy strategy is raised to further reduce the implementation area of MDS matrix patterns by introducing a few Type-2 elementary matrices. In comparison to previous methods, our approach is more general and effective for constructing lower-area MDS matrices. To demonstrate the efficiency of our method, we apply the framework on constructing m x m MDS matrices over F2n or GL(n, F2), where m ∈ {4, 5, 6, 7, 8} and n ∈ {4, 8, 16, 32, 64}. The 4 x 4 MDS matrices constructed by our method can also reach the minimum area. The 5 x 5, 6 x 6 and 7 x 7 MDS matrices constructed by our method have lower area compared to previous ones. While the 8 x 8 MDS matrices with n ∈ {16, 32, 64} constructed by our method also have lower area compared to previous ones
VIMA: A Privacy-Preserving Integrity Measurement Architecture for Containerized Environments
No full textIntegrity verification and attestation are critical in containerized environments, where traditional Linux Integrity Measurement Architecture (IMA) falls short due to its lack of container-specific contextualization. These gaps undermine container autonomy, escalate privacy risks, and impede granular integrity checks. Addressing these challenges, this paper introduces the Virtual IMA (VIMA), a novel framework that refines Linux IMA’s principles to support containerized settings. Using nested Merkle trees, VIMA’s Two-Tree Architecture (2TA) enables detailed integrity assessments across system-wide monolithic trees and individual container trees. Integrating Merkle and zero-knowledge (ZK) proofs establishes VIMA as a secure, privacy-preserving verification and attestation solution. Our comparative analysis and initial prototype testing reveal that VIMA significantly improves upon traditional IMA with minimal performance overhead, offering substantial scope for optimization
Ramon Bacardit: Primera lliçó sobre Àngel Guimerà. Barcelona: Publicacions de l\u27Abadia de Montserrat, 2023
Get PDF«Chapurriau como lo han llamado siempre». Origen del glotònim xapurriau a la Franja (primera meitat del s. XX)
Get PDF“Chapurrear” is defined as “to speak a language with difficulty and make mistakes” (RAE, 2023). This article examines the historical use of the term Chapurriau to refer to the language spoken within the Catalan-speaking region of Aragon (the Franja). It systematically examines its earliest recorded appearances in written public discourse and finds no evidence that Chapurriau appeared in written form before the 20th century. This absence contrasts with historical references to the language as Catalan or Limousin. The article suggests that debates over glottonyms, or clearly associated with the idea of linguistic mixture, are closely linked to its historical loss of functions and can thus be understood as symptoms of its decline.“Chapurrear” is defined as “to speak a language with difficulty and make mistakes” (RAE, 2023). This article examines the historical use of the term Chapurriau to refer to the language spoken within the Catalan-speaking region of Aragon (the Franja). It systematically examines its earliest recorded appearances in written public discourse and finds no evidence that Chapurriau appeared in written form before the 20th century. This absence contrasts with historical references to the language as Catalan or Limousin. The article suggests that debates over glottonyms, or clearly associated with the idea of linguistic mixture, are closely linked to its historical loss of functions and can thus be understood as symptoms of its decline
Ofèlia Dracs i la recepció d\u27H.P. Lovecraft a la literatura catalana
No full textThe book of short stories Lovecraft, Lovecraft! (1981) by the Catalan collective Ofèlia Dracs has been harshly judged by critics for failing to reach the tone and level of H.P. Lovecraft’s stories. This paper suggests that such judgments have been made on the basis of two false postulates. First, it has been interpreted that the purpose of this volume was to pay homage to Lovecraft, when in fact, as defended here, the purpose was to write horror stories, a genre that is hardly cultivated in Catalan literature and that the Ofèlia Dracs collective intends to promote. Secondly, these stories have been evaluated as if they had been written by a single author, when in fact they are the work of ten individual authors. A specific analysis of each of the stories shows the ways in which each of the authors tried to contribute to this collective purpose, concluding that the volume deserves a place in the history of the horror genre in Catalan literature.The book of short stories Lovecraft, Lovecraft! (1981) by the Catalan collective Ofèlia Dracs has been harshly judged by critics for failing to reach the tone and level of H.P. Lovecraft’s stories. This paper suggests that such judgments have been made on the basis of two false postulates. First, it has been interpreted that the purpose of this volume was to pay homage to Lovecraft, when in fact, as defended here, the purpose was to write horror stories, a genre that is hardly cultivated in Catalan literature and that the Ofèlia Dracs collective intends to promote. Secondly, these stories have been evaluated as if they had been written by a single author, when in fact they are the work of ten individual authors. A specific analysis of each of the stories shows the ways in which each of the authors tried to contribute to this collective purpose, concluding that the volume deserves a place in the history of the horror genre in Catalan literature
