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Polarization transfer to a bound proton in polarized electron knock-out reactions, $\mathrm{A}(\vec{e},e^{\prime}\vec{p})$, is a powerful tool to look for in-medium modification of the bound proton. It requires comparison to calculations which consider the many-body effects accompanying the quasi-free process. We report here measured components $P_x^{\prime}$, $P_z^{\prime}$, and their ratio $P_x^{\prime}/P_z^{\prime}$, of polarization transfer to protons bound in $^{40}\mathrm{Ca}$, which is described well by the shell model and for which reliable calculations are available. While the calculations capture the essence of the data, our statistical precision allows us to observe deviations which cannot be explained by simple scaling, including by varying the proton electromagnetic form factor ratio $G_E/G_M$. We further explore the deviations of the ratio of the polarization transfer components from that of a free proton, $(P_x^{\prime}/P_z^{\prime})_{\rm A}/(P_x^{\prime}/P_z^{\prime})_{\rm H}$, and its dependence on the bound-proton virtuality.

Trusted execution environments (TEEs) provide an environment for running workloads in the cloud without having to trust cloud service providers, by offering additional hardware-assisted security guarantees. However, main memory encryption as a key mechanism to protect against system-level attackers trying to read the TEE's content and physical, off-chip attackers, is insufficient. The recent Cipherleaks attacks infer secret data from TEE-protected implementations by analyzing ciphertext patterns exhibited due to deterministic memory encryption. The underlying vulnerability, dubbed the ciphertext side-channel, is neither protected by state-of-the-art countermeasures like constant-time code nor by hardware fixes. Thus, in this paper, we present a software-based, drop-in solution that can harden existing binaries such that they can be safely executed under TEEs vulnerable to ciphertext side-channels, without requiring recompilation. We combine taint tracking with both static and dynamic binary instrumentation to find sensitive memory locations, and mitigate the leakage by masking secret data before it gets written to memory. This way, although the memory encryption remains deterministic, we destroy any secret-dependent patterns in encrypted memory. We show that our proof-of-concept implementation protects various constant-time implementations against ciphertext side-channels with reasonable overhead., Jan Wichelmann and Anna P\"atschke contributed equally to this work

The Institute of Space Systems (IRS) of the University of Stuttgart is currently analysing a mission to explore the inner Van Allen radiation belt using a small satellite of about 60 kg. The satellite shall be launched to an orbit of approximately 600 km and then use its orbital control system to reach an elliptical orbit of 330 km × 2500 km. In addition to the scientific mission goals, the mission shall demonstrate new components in the harsh radiation environment; these include an orbit control system using water-based propulsion, a highly integrated core avionic system and a ham radio X-Band data downlink system. The data downlink system for this mission is currently being developed at the IRS. Due to the highly elliptic final orbit, the need for an adaptive data downlink transmitter platform arises, that is capable of adapting its waveform to the current link conditions. Moreover, this transmitter shall be fully compliant with the Consultative Committee for Space Data System (CCSDS) recommendations for the physical and the data link layers while implementing the adaptive coding and modulation of the Digital Video Broadcast – Second Generation (DVB-S2) standard. Furthermore, this development focusses on low-power consumption, use of commercial-off-the-shelf components, re-configurability and miniaturisation. The transmitter platform is based on a System on a Chip which implements the CCSDS as well as the DVB-S2 protocol stacks. The analog components are chosen to provide possible scaling of the platform to commercial X-Band, Ku and Ka-Band. The transmitter is able to support data rates up to 200 Mbps and delivers up to 2 Watts RF power. The use of the DVB-S2 standard allows to increase the downlink capacity by 66% using variable coding and modulation. An increase by 130% or even more is possible using adaptive coding and modulation. This adaptive platform is crucial for the mission success in order to transmit the high data volume, which could not be downlinked with a platform using a fixed waveform only. The increase in downlink capacity by adapting to the link conditions can also be useful for other missions, e.g. where ground terminals are located in regions with high rain loss or for satellite constellations where each satellite has limited ground station contact. The development of this transmitter platform that can be adapted in nearly-real time to the existing link conditions is presented in this paper.

Secret-dependent timing behavior in cryptographic implementations has resulted in exploitable vulnerabilities, undermining their security. Over the years, numerous tools to automatically detect timing leakage or even to prove their absence have been proposed. However, a recent study at IEEE S&P 2022 showed that, while many developers are aware of one or more analysis tools, they have major difficulties integrating these into their workflow, as existing tools are tedious to use and mapping discovered leakages to their originating code segments requires expert knowledge. In addition, existing tools focus on compiled languages like C, or analyze binaries, while the industry and open-source community moved to interpreted languages, most notably JavaScript. In this work, we introduce Microwalk-CI, a novel side-channel analysis framework for easy integration into a JavaScript development workflow. First, we extend existing dynamic approaches with a new analysis algorithm, that allows efficient localization and quantification of leakages, making it suitable for use in practical development. We then present a technique for generating execution traces from JavaScript applications, which can be further analyzed with our and other algorithms originally designed for binary analysis. Finally, we discuss how Microwalk-CI can be integrated into a continuous integration (CI) pipeline for efficient and ongoing monitoring. We evaluate our analysis framework by conducting a thorough evaluation of several popular JavaScript cryptographic libraries, and uncover a number of critical leakages.

The term operating system refers to a software component, which traditionally controls the resources and the processes of a computer, and by providing the appropriate interfaces allows for the implementation of custom user applications. This is a common definition, working very well for ordinary computer systems. Yet, what if the operating system and a corresponding application are physically separated, because the computer is within a satellite in space, while the user program is executed on ground? Then, capabilities must be created to connect both, which is of course complicated by the natural boundaries in satellite communication, for example the limited satellite contact times. Over the past decades, several systems have been developed, which are capable of managing satellite resources and the mission schedule from ground. Although this covers quite well the purpose of an operating system, other terms have evolved in this domain: operations system, ground system, mission control system, ground data handling, etc. The problem though is, those systems primarily focus on the exchange of data and satellite TM/TC, rather than the actual control process. This creates an artificial barrier between ground and space, which harms the development capabilities for ground based satellite applications. This paper introduces a novel approach for an operations system architecture, which can be considered as a ground extension of the satellite’s operating system. This approach shall not break with the existing conventions and definitions, especially in terms of operating systems, but shall introduce a new view on satellite operations. In a layered, functional software architecture, the operating system is the lowest layer between the hardware and the application. Through the definition of the appropriate interfaces in the ground system, a software architecture can be created that actively supports outsourcing parts of the satellite control process to ground. The proposed approach has great potential for various applications in satellite operations. It supports the implementation of automatic system control processes, the implementation of custom payload applications, and the integration of respective activities into the satellite schedule. As applications and operators interact with a verified schedule, and operations is thus no longer limited to low-level commanding, the approach further reduces the risk of the mission being jeopardized by human mistake.

The volume of data generated by Earth observation satellites has drastically increased in the last years. Consequently, more RF bandwidth is required to download data to ground, and migration to higher frequency is an option. However, the limited resources on small satellite platforms regarding volume, mass and DC power limit the enhancement of bandwidth. The research reported here focusses on the enhancement of integrity, re-configurability and miniaturization. Furthermore, cost-efficient solutions are studied for implementation of high bandwidth downlinks on small satellites. Clearly, a bandwidth-efficient implementation and a migration from the ham radio S-band to the corresponding X-band will increase the download capacity. Low-cost ground receivers, which support the telecommunication standard DVB-S2, are available. DVB-S2 can be adapted for small satellite applications by implementing the Consultative Committee for Space Data System (CCSDS) standard above DVB-S2 in the protocol stack. DVB-S2 supports constant, variable as well as adaptive coding and modulation. Thus, the modulation and coding scheme can change on a frame-by-frame basis depending on channel conditions. In this paper, we describe the development of an own-developed low-cost flexible radio platform by using commercial-off-the-shelf components. An FPGA-based architecture for implementing CCSDS above DVB-S2 protocol stack is presented. This design is capable to compensate for changes in the link conditions, increasing download capacity by 66% for variable and by 130% for adaptive coding and modulation. This increase is crucial for ground terminals located in regions with high rain loss such as South-Asia, or for satellite constellations in low-earth orbit where each satellite has a limited ground station contact window.

We provide evidence for axonal regeneration in the central nervous system (CNS) of the locust (Locusta migratoria). We followed the morphology of a small set of proctolin-immunoreactive neurons in the ventral nerve cord before and after crushing one cervical connective in the third instar. The proximal segments started sprouting within 3 days post lesion and grew into the suboesophageal ganglion within 9 days, covering a distance of approximately 2 mm. Within the suboesophageal ganglion, the regenerated neurites formed arborisations in the appropriate region which closely resemble the original shape. These findings will allow us to compare regeneration to the well-described embryonic development of axonal connectivity in this animal.

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