Christoph Ludwig

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We propose a practical sampling reduction algorithm for lattice bases based on work by Schnorr [1] as well as two even more effective generalizations. We report the empirical behaviour of these algorithms. We describe how Sampling Reduction allows to stage lattice attacks against the NTRU cryptosystem with smaller BKZ parameters than before and conclude(More)
We report experiments on the security of the GGH-like cryp-tosystem proposed by Micciancio. Based on these experiments, we conclude that the system can be securely used only in lattice dimensions ≥ 782. Further experiments on the efficiency of the system show that it requires key sizes of 1 MByte and more and that the key generation as well as the(More)
Digital signatures have become a key technology for making the Internet and other IT infrastructures secure. But in 1994 Peter Shor showed that quantum computers can break all digital signature schemes that are used today and in 2001 Chuang and his coworkers implemented Shor's algorithm for the first time on a 7-qubit NMR quantum computer. This paper(More)
Change is a constant (not only) in the Semantic Web. Both instance data and ontologies evolve. These changes are a piecemeal process, morphing from version to version both for conceptualizations / ontologies and for the related instance data / individuals. Individual versions capture valuable information about ontologies and instance data that were valid at(More)
The established techniques for legal-for-trade registration of weight values meet the legal requirements, but in praxis they show serious disadvantages. We report on the first implementation of intrinsically legal-for-trade objects, namely weight values signed by the scale, that is accepted by the approval authority. The strict requirements from both the(More)
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