QuanShield: Protecting against Side-Channels Attacks using Self-Destructing Enclaves

Trusted Execution Environments (TEEs) allow user processes to create enclaves that protect security-sensitive computation against access from the OS kernel and the hypervisor. Recent work has shown that TEEs are vulnerable to side-channel attacks that allow an adversary to learn secrets shielded in enclaves. The majority of such attacks trigger exceptions or interrupts to trace the control or data flow of enclave execution. We propose QuanShield, a system that protects enclaves from side-channel attacks that interrupt enclave execution. The main idea behind QuanShield is to strengthen resource isolation by creating an interrupt-free environment on a dedicated CPU core for running enclaves in which enclaves terminate when interrupts occur. QuanShield avoids interrupts by exploiting the tickless scheduling mode supported by recent OS kernels. QuanShield then uses the save area (SA) of the enclave, which is used by the hardware to support interrupt handling, as a second stack. Through an LLVM-based compiler pass, QuanShield modifies enclave instructions to store/load memory references, such as function frame base addresses, to/from the SA. When an interrupt occurs, the hardware overwrites the data in the SA with CPU state, thus ensuring that enclave execution fails. Our evaluation shows that QuanShield significantly raises the bar for interrupt-based attacks with practical overhead.Comment: 15pages, 5 figures, 5 table

The multichannel discharge plasma synthetic jet actuator

The plasma synthetic jet actuator (PSJA) is a flow control device capable of generating high speed pulsed jet. However, the performance of conventional PSJA is restricted by low discharge efficiency and small control area, because one power supply only drives one electrode couple. The present work is to propose a new concept of multichannel discharge plasma synthetic jet actuator (MD-PSJA), which is driven by single power supply. The new MD-PSJA has two types, namely the multi-electrode PSJA and the multi-PSJA array. These two types of MD-PSJA are examined experimentally. The multi-electrode PSJA containing 11-electrode PSJA is first studied. Comparison with standard 2-electrode PSJA reveals that the discharge efficiency and jet velocity increase 200% and 47% respectively under the same input energy and discharge voltage. The multi-PSJA array is later evaluated. One power supply is found to be able to drive an array of 12 PSJAs, resulting in 6 times affected area and 64% jet velocity of a conventional PSJA. The proposed MD-PSJA is finally concluded an improved active flow control actuator in high speed applications

Atypical location of primary cardiac lymphoma in the left heart with atypical clinical presentation: A case report and literature review

BackgroundPrimary cardiac lymphoma (PCL) is a rare and aggressive cardiac tumor with very poor prognosis that occurs mostly in the right cardiac cavity. Early diagnosis and treatment may improve its prognosis. In the present report, we describe the diagnosis and treatment of a primary cardiac diffuse large B-cell lymphoma (PC-DLBCL) with atypical location and clinical presentation. Additionally, a literature review was conducted to summarize the current knowledge of the disease.Case PresentationA 71-year-old man visited his local hospital because of syncope, recurrent chest tightness, shortness of breath, palpitations, and profuse sweating for more than 20 days. Chest radiography revealed a mediastinal mass. Cardiac computed tomography (CT) showed multiple enlarged mediastinal lymph nodes. Transthoracic echocardiography (TTE) showed a cardiac mass in the posterior–inferior wall of the left atrium. He was then transferred to our hospital for positron emission tomography-CT (PET-CT) which showed active uptake of fluorodeoxyglucose both in the cardiac mass and in the multiple enlarged mediastinal lymph nodes. Biopsy of the enlarged mediastinal lymph nodes was carried out by using video-assisted thoracic surgery (VATS) technique, and pathological examination confirmed the subtype of PC-DLBCL, Stage IV, NCCN IPI 3. Therefore, the patient received a combination of chemotherapy and immunotherapy with R-CDOP (rituximab, cyclophosphamide, liposome doxorubicin, vincristine, and prednisone). After four courses of treatment in 4 months, the cardiac lymphoma and the enlarged mediastinal lymph nodes achieved complete remission with mild side effects of the chemotherapy.ConclusionEarly diagnosis and a precise choice of chemotherapy and immunotherapy based on cardiac imaging and pathological examination may improve the prognosis of PC-DLBCL in an atypical location

Bright broadband coherent fiber sources emitting strongly blue-shifted resonant dispersive wave pulses

We predict and realize the targeted wavelength conversion from the 1550-nm band of a fs Er:fiber laser to an isolated band inside 370-850 nm, corresponding to a blue-shift of 700-1180 nm. The conversion utilizes resonant dispersive wave generation in widely available optical fibers with good efficiency (~7%). The converted band has a large pulse energy (~1 nJ), high spectral brightness (~1 mW/nm), and broad Gaussian-like spectrum compressible to clean transform-limited ~17 fs pulses. The corresponding coherent fiber sources open up portable applications of optical parametric oscillators and dual-output synchronized ultrafast lasers

Role of Alkaline-Earth Metal-Catalyst: A Theoretical Study of Pyridines Hydroboration

Density functional theory (DFT) calculations have been performed to investigate the mechanism of alkaline-earth-metal-catalyzed hydroboration of pyridines with borane. In this reaction, the active catalytic species is considered to be an alkaline earth metal hydride complex when the corresponding alkaline earth metal is used as the catalyst. The theoretical results reveal that initiation of the catalytic cycle is hydride transfer to generate a magnesium hydride complex when β-diimine alkylmagnesium is used as a pre-catalyst. The magnesium hydride complex can undergo coordination of the pyridine reactant followed by hydride transfer to form a dearomatized magnesium pyridine intermediate. Coordination of borane and hydride transfer from borohydride to magnesium then give the hydroboration product and regenerate the active magnesium hydride catalyst. The rate-determining step of the catalytic cycle is hydride transfer to pyridine with a free energy barrier of 29.7 kcal/mol. Other alkaline earth metal complexes, including calcium and strontium complexes, were also considered. The DFT calculations show that the corresponding activation free energies for the rate-determining step of this reaction with calcium and strontium catalysts are much lower than with the magnesium catalyst. Therefore, calcium and strontium complexes can be used as the catalyst for the reaction, which could allow mild reaction conditions