Cryptanalysis of the McEliece Cryptosystem on GPGPUs

The linear code based McEliece cryptosystem is potentially promising as a so-called post-quantum public key cryptosystem because thus far it has resisted quantum cryptanalysis, but to be considered secure, the cryptosystem must resist other attacks as well. In 2011, Bernstein et al. introduced the Ball Collision Decoding (BCD) attack on McEliece which is a significant improvement in asymptotic complexity over the previous best known attack. We implement this attack on GPUs, which offer a parallel architecture that is well-suited to the matrix operations used in the attack and decrease the asymptotic run-time. Our implementation executes the attack more than twice as fast as the reference implementation and could be used for a practical attack on the original McEliece parameters

Theory for the FCC-ee : Report on the 11th FCC-ee Workshop

The Future Circular Collider (FCC) at CERN, a proposed 100-km circular facility with several colliders in succession, culminates with a 100 TeV proton-proton collider. It offers a vast new domain of exploration in particle physics, with orders of magnitude advances in terms of Precision, Sensitivity and Energy. The implementation plan foresees, as a first step, an Electroweak Factory electron-positron collider. This high luminosity facility, operating between 90 and 365 GeV centre-of-mass energy, will study the heavy particles of the Standard Model, Z, W, Higgs, and top with unprecedented accuracy. The Electroweak Factory $e^+e^-$ collider constitutes a real challenge to the theory and to precision calculations, triggering the need for the development of new mathematical methods and software tools. A first workshop in 2018 had focused on the first FCC-ee stage, the Tera-Z, and confronted the theoretical status of precision Standard Model calculations on the Z-boson resonance to the experimental demands. The second workshop in January 2019, which is reported here, extended the scope to the next stages, with the production of W-bosons (FCC-ee-W), the Higgs boson (FCC-ee-H) and top quarks (FCC-ee-tt). In particular, the theoretical precision in the determination of the crucial input parameters, alpha_QED, alpha_QCD, M_W, m_t at the level of FCC-ee requirements is thoroughly discussed. The requirements on Standard Model theory calculations were spelled out, so as to meet the demanding accuracy of the FCC-ee experimental potential. The discussion of innovative methods and tools for multi-loop calculations was deepened. Furthermore, phenomenological analyses beyond the Standard Model were discussed, in particular the effective theory approaches. The reports of 2018 and 2019 serve as white papers of the workshop results and subsequent developments

Parallelization of Integer Factorization from the View of RSA Breaking

Práce se zabývá faktorizací celých čísel. Faktorizace je nejznámější a nejpoužívanější metodou kryptoanalýzy RSA. V rámci této práce byla vybrána a implementována faktorizační metoda zvaná SIQS. I když se jedná o nejrychlejší metodu (do 100 dekadických číslic), není možné ji efektivně počítat v polynomiálním čase, a tak  se hledají různé možnosti, jak tuto metodu co nejvíce urychlit. Jako první se nabízí paralelizace. K tomuto účelu bylo využito OpenMP. Další možností je optimalizace kódu. Cílem této práce je také ukázat, jak jednoduše lze v mnoha případech využít paralelizace kódu a dále, jak díky podrobné analýze kódu lze dosáhnout poměrně velkého urychlení. Použitá metodika iteračního provádění optimalizací se ukázala jako velmi účinná. Touto metodikou byla implementace SIQS vylepšena tak, že faktorizace byla urychlena až 100-krát, v některých částech kódu dokonce ještě více.This paper follows up the factorization of integers. Factorization is the most popular and used method for RSA cryptoanalysis. The SIQS was chosen as a factorization method that will be used in this paper. Although SIQS is the fastest method (up to 100 digits), it can't be effectively computed at polynomial time, so it's needed to look up for options, how to speed up the method as much as possible. One of the possible ways is paralelization. In this case OpenMP was used. Other possible way is optimalization. The goal of this paper is also to show, how easily is possible to use paralelizion and thanks to detailed analyzation the source codes one can reach relatively large speed up. Used method of iterative optimalization showed itself as a very effective tool. Using this method the implementation of SIQS achieved almost 100 multiplied speed up and at some parts of the code even more.

Pseudo-contractions as Gentle Repairs

Updating a knowledge base to remove an unwanted consequence is a challenging task. Some of the original sentences must be either deleted or weakened in such a way that the sentence to be removed is no longer entailed by the resulting set. On the other hand, it is desirable that the existing knowledge be preserved as much as possible, minimising the loss of information. Several approaches to this problem can be found in the literature. In particular, when the knowledge is represented by an ontology, two different families of frameworks have been developed in the literature in the past decades with numerous ideas in common but with little interaction between the communities: applications of AGM-like Belief Change and justification-based Ontology Repair. In this paper, we investigate the relationship between pseudo-contraction operations and gentle repairs. Both aim to avoid the complete deletion of sentences when replacing them with weaker versions is enough to prevent the entailment of the unwanted formula. We show the correspondence between concepts on both sides and investigate under which conditions they are equivalent. Furthermore, we propose a unified notation for the two approaches, which might contribute to the integration of the two areas

Solidification and Gravity VII

International audienc