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1. Shielding Software From Privileged Side-Channel Attacks

   Dong, Xiaowan; Shen, Zhuojia; Criswell, John; Cox, Alan L.; Dwarkada, Sandhya (August 2018, Proceedings of the Twenty Seventh Usenix Security Symposium)

   Commodity operating system (OS) kernels, such as Windows, Mac OS X, Linux, and FreeBSD, are susceptible to numerous security vulnerabilities. Their monolithic design gives successful attackers complete access to all application data and system resources. Shielding systems such as InkTag, Haven, and Virtual Ghost protect sensitive application data from compromised OS kernels. However, such systems are still vulnerable to side-channel attacks. Worse yet, compromised OS kernels can leverage their control over privileged hardware state to exacerbate existing side channels; recent work has shown that a compromised OS kernel can steal entire documents via side channels. This paper presents defenses against page table and last-level cache (LLC) side-channel attacks launched by a compromised OS kernel. Our page table defenses restrict the OS kernel’s ability to read and write page table pages and defend against page allocation attacks, and our LLC defenses utilize the Intel Cache Allocation Technology along with memory isolation primitives. We proto- type our solution in a system we call Apparition, building on an optimized version of Virtual Ghost. Our evaluation shows that our side-channel defenses add 1% to 18% (with up to 86% for one application) overhead to the optimized Virtual Ghost (relative to the native kernel) on real-world applications. 

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2. GMRES, pseudospectra, and Crouzeix’s conjecture for shifted and scaled Ginibre matrices

   https://doi.org/10.1090/mcom/3963  

   Chen, Tyler; Greenbaum, Anne; Trogdon, Thomas (March 2024, Mathematics of Computation)

   We study the GMRES algorithm applied to linear systems of equations involving a scaled and shifted $N\times <\#comment/>N$matrix whose entries are independent complex Gaussians. When the right-hand side of this linear system is independent of this random matrix, the $N\to <\#comment/>\mathrm{\infty <\#comment/>}$behavior of the GMRES residual error can be determined exactly. To handle cases where the right hand side depends on the random matrix, we study the pseudospectra and numerical range of Ginibre matrices and prove a restricted version of Crouzeix’s conjecture. 

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3. Energetic Control of Redox‐Active Polymers toward Safe Organic Bioelectronic Materials

   https://doi.org/10.1002/adma.201908047  

   Giovannitti, Alexander; Rashid, Reem_B; Thiburce, Quentin; Paulsen, Bryan_D; Cendra, Camila; Thorley, Karl; Moia, Davide; Mefford, J_Tyler; Hanifi, David; Weiyuan, Du; et al (March 2020, Advanced Materials)

   Abstract Avoiding faradaic side reactions during the operation of electrochemical devices is important to enhance the device stability, to achieve low power consumption, and to prevent the formation of reactive side‐products. This is particularly important for bioelectronic devices, which are designed to operate in biological systems. While redox‐active materials based on conducting and semiconducting polymers represent an exciting class of materials for bioelectronic devices, they are susceptible to electrochemical side‐reactions with molecular oxygen during device operation. Here, electrochemical side reactions with molecular oxygen are shown to occur during organic electrochemical transistor (OECT) operation using high‐performance, state‐of‐the‐art OECT materials. Depending on the choice of the active material, such reactions yield hydrogen peroxide (H₂O₂), a reactive side‐product, which may be harmful to the local biological environment and may also accelerate device degradation. A design strategy is reported for the development of redox‐active organic semiconductors based on donor–acceptor copolymers that prevents the formation of H₂O₂during device operation. This study elucidates the previously overlooked side‐reactions between redox‐active conjugated polymers and molecular oxygen in electrochemical devices for bioelectronics, which is critical for the operation of electrolyte‐gated devices in application‐relevant environments. 

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4. iSTELAN: Disclosing Sensitive User Information by Mobile Magnetometer from Finger Touches

   https://doi.org/10.56553/popets-2023-0042  

   Mohamed, Reham; Farrukh, Habiba; Lu, Yidong; Wang, He; Celik, Z. Berkay (April 2023, Proceedings on Privacy Enhancing Technologies)

   We show a new type of side-channel leakage in which the built-in magnetometer sensor in Apple's mobile devices captures touch events of users. When a conductive material such as the human body touches the mobile device screen, the electric current passes through the screen capacitors generating an electromagnetic field around the touch point. This electromagnetic field leads to a sharp fluctuation in the magnetometer signals when a touch occurs, both when the mobile device is stationary and held in hand naturally. These signals can be accessed by mobile applications running in the background without requiring any permissions. We develop iSTELAN, a three-stage attack, which exploits this side-channel to infer users' application and touch data. iSTELAN translates the magnetometer signals to a binary sequence to reveal users' touch events, exploits touch event patterns to fingerprint the type of application a user is using, and models touch events to identify users' touch event types performed on different applications. We demonstrate the iSTELAN attack on 22 users while using 7 popular app types and show that it achieves an average accuracy of 90% for disclosing touch events, 74% for classifying application type used, and 73% for detecting touch event types. 

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5. Specimen plane orientation determination for analysis based on scanning electron microscope: Comparing top‐down and side‐view approaches

   https://doi.org/10.1002/jemt.24404  

   Li, Chunfei; Craig, Joshua; Dubovi, Josiah (August 2023, Microscopy Research and Technique)

   Abstract Many attachments to a scanning electron microscope (SEM), such as energy dispersive x‐ray spectroscopy, extend its function significantly. Typically, the application of such attachments requires that the specimen has a planar surface at a specific orientation. It is a challenge to make the plane of a microscale specimen satisfy the orientation requirement since they are visible only in an SEM. An in‐situ procedure is needed to adjust specimen orientation by using stage rotation and tilting functions, in the process of which the key is to determine the initial orientation. This study proposed and tested top‐down and side‐view approaches to determine the orientation of a planar surface inside an SEM. In the top‐down one, the projected area is monitored on SEM images as stage rotation and tilt angles are adjusted. When the surface normal is along the electron beam direction, the area has a maximum value. In the side‐view approach, the stage is adjusted so that the projection appears to be a straight horizontal line on the SEM image. Once the orientation of the specimen for top‐down or side‐view observation is determined, the original can be calculated, and a desired orientation can be realized by manipulating the stage. The procedures have been tested by analyzing planar surfaces of spherical particles in Al‐Cu‐Fe alloy in the form of facets. The measured angles between two surfaces are consistent with those expected from crystallographic consideration within 2.7° and 1.7° for the top‐down and side‐view approaches, respectively. Research HighlightsTop‐down and side‐view approaches have been proposed and tested for in‐situ determination of specimen planar surface orientation in a Scanning Electron Microscope.The measured angles between two surfaces are consistent with those expected from crystallographic consideration within 2.7° and 1.7° for the top‐down and side‐view approaches, respectively. 

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