Fraunhofer-Publica
The Fraunhofer-Publica has been successfully documenting the research results of the Fraunhofer-Gesellschaft for over 30 years. The platform enables the collaborative linking of research-relevant objects and disseminates within the international scientific community.
The Fraunhofer-Publica thus fulfils its responsibility to promote the transfer of knowledge and know-how to industry and society.
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Research outputs
As an application-oriented research organisation, Fraunhofer aims to conduct highly innovative and solution-oriented research - for the benefit of society and to strengthen the German and European economy.
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Projects
Fraunhofer is tackling the current challenges facing industry head on. By pooling their expertise and involving industrial partners at an early stage, the Fraunhofer Institutes involved in the projects aim to turn original scientific ideas into marketable products as quickly as possible.
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Researchers
Scientific achievement and practical relevance are not opposites - at Fraunhofer they are mutually dependent. Thanks to the close organisational links between Fraunhofer Institutes and universities, science at Fraunhofer is conducted at an internationally first-class level.
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Institutes
The Fraunhofer-Gesellschaft is the leading organisation for applied research in Europe. Institutes and research facilities work under its umbrella at various locations throughout Germany.
Recent Additions
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PublicationExploring quantum synchronization with a composite two-qubit oscillator( 2024)Synchronization has recently been explored deep in the quantum regime with elementary few-level quantum oscillators such as qudits and weakly pumped quantum van der Pol oscillators. To engineer more complex quantum synchronizing systems, it is practically relevant to study composite oscillators built from basic quantum units that are commonly available and offer high controllability. Here we consider a minimal model for a composite oscillator consisting of two interacting qubits coupled to separate baths and show that this system exhibits a wide variety of synchronizing behaviors. We study the phase response of the constituent qubits as well as the system as a whole, when one of the qubits is weakly driven. We consider the thermal baths to have positive as well as effective negative temperatures and discover effects that occur only when the temperatures of the baths for the two qubits are of opposite signs. We propose and analyze a circuit quantum electrodynamics implementation of this model, which exploits recent advances in dissipation engineering to realize effective negative temperature baths. Our work demonstrates the potential for assembling complex quantum synchronizing systems from basic building units, which is of pragmatic importance for advancing the field of quantum synchronization.
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PublicationPoster: Longitudinal Analysis of DoS Attacks( 2023)Denial-of-Service (DoS) attacks have become a regular occurrence in the digital world of today. Easy-to-use attack software via download and botnet services that can be rented cheaply in the darknet enable adversaries to conduct such attacks without requiring a comprehensive knowledge of the techniques. To investigate this threat, we conduct a study on DoS attacks that occurred between 1 January 2015 and 31 December 2022. We gather statistics regarding the victims and on how the attacks were conducted. Furthermore, we show possible side effects of such attacks on critical Internet infrastructure. This study provides interesting insights as well as observations and is useful for researchers and experts for developing defenses to mitigate DoS attacks. We therefore make our dataset publicly available.
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Mainwork
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PublicationLoop Aborts Strike Back: Defeating Fault Countermeasures in Lattice Signatures with ILP( 2023)At SAC 2016, Espitau et al. presented a loop-abort fault attack against lattice-based signature schemes following the Fiat–Shamir with aborts paradigm. Their attack recovered the signing key by injecting faults in the sampling of the commitment vector (also called masking vector) y, leaving its coefficients at their initial zero value. As possible countermeasures, they proposed to carry out the sampling of the coefficients of y in shuffled order, or to ensure that the masking polynomials in y are not of low degree. In this paper, we show that both of these countermeasures are insufficient. We demonstrate a new loop-abort fault injection attack against Fiat–Shamir with aborts lattice-based signatures that can recover the secret key from faulty signatures even when the proposed countermeasures are implemented. The key idea of our attack is that faulted signatures give rise to a noisy linear system of equations, which can be solved using integer linear programming. We present an integer linear program that recovers the secret key efficiently in practice, and validate the efficacy of our attack by conducting a practical end-to-end attack against a shuffled version of the Dilithium reference implementation, mounted on an ARM Cortex M4. We achieve a full (equivalent) key recovery in under 3 minutes total execution time (including signature generation), using only 5 faulted signatures. In addition, we conduct extensive theoretical simulations of the attack against Dilithium. We find that our method can achieve key recovery in under 5 minutes given a (sufficiently large) set of signatures where just one of the coefficients of y is zeroed out (or left at its initial value of zero). Furthermore, we find that our attack works against all security levels of Dilithium. Our attack shows that protecting Fiat–Shamir with aborts lattice-based signatures against fault injection attacks cannot be achieved using the simple countermeasures proposed by Espitau et al. and likely requires significantly more expensive countermeasures.
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PublicationHierarchical Clock Synchronization in MPI( 2018)MPI benchmarks are used for analyzing or tuning the performance of MPI libraries. Generally, every MPI library should be adjusted to the given parallel machine, especially on supercomputers. System operators can define which algorithm should be selected for a specific MPI operation, and this decision which algorithm to select is usually made after analyzing bench-mark results. The problem is that the latency of communication operations in MPI is very sensitive to the chosen data acquisition and data processing method. For that reason, depending on how the performance is measured, system operators may end up with a completely different MPI library setup. In the present work, we focus on the problem of precisely measuring the latency of collective operations, in particular, for small payloads, where external experimental factors play a significant role. We present a novel clock synchronization algorithm, which exploits the hierarchical architecture of compute clusters, and we show that it outperforms previous approaches, both in run-time and in precision. We also propose a different scheme to obtain precise MPI run-time measurements (called Round-Time), which is based on given, fixed time slices, as opposed to the traditional way of measuring for a predefined number of repetitions. We also highlight that the use of MPI_Barrier has a significant effect on experimentally determined latency values of MPI collectives. We argue that MPI_Barrier should be avoided if the average run-time of the barrier function is in the same order of magnitude as the run-time of the MPI function to be measured.
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PublicationCharacterization of self-cleaning properties on superhydrophobic aluminum surfaces fabricated by direct laser writing and direct laser interference patterning( 2020)Self-cleaning ability on technical surfaces can increase the added value of a product. A common path to achieve this property is making the surface superhydrophobic so that water droplets can roll down, picking up dirt particles. In this contribution, the self-cleaning efficiency of Al surfaces structured with direct laser writing (DLW), direct laser interference patterning (DLIP) and a combination of both technologies was quantitatively determined. This was performed by developing a characterization method, where the treated samples are firstly covered with either MnO2 or polyamide micro-particles, then tilted by 15° and 30° and finally washed applying up to nine water droplets (10 µl) over the contaminated surfaces. Then, an optical analysis by image processing of the remaining contamination particles on the textured surfaces was realized after each droplet rolled over the surface. The DLIP textures showed the best performance, allowing the removal of more than 90% of the particles after just three droplets were released. High-speed videos and scanning electron microscopy characterization allowed a deeper understanding on the cleaning behavior and on the relationship between surface microstructure and particle size and shape.