CacheZoom: How SGX Amplifies The Power of Cache Attacks

In modern computing environments, hardware resources are commonly shared, and parallel computation is widely used. Parallel tasks can cause privacy and security problems if proper isolation is not enforced. Intel proposed SGX to create a trusted execution environment within the processor. SGX relies on the hardware, and claims runtime protection even if the OS and other software components are malicious. However, SGX disregards side-channel attacks. We introduce a powerful cache side-channel attack that provides system adversaries a high resolution channel. Our attack tool named CacheZoom is able to virtually track all memory accesses of SGX enclaves with high spatial and temporal precision. As proof of concept, we demonstrate AES key recovery attacks on commonly used implementations including those that were believed to be resistant in previous scenarios. Our results show that SGX cannot protect critical data sensitive computations, and efficient AES key recovery is possible in a practical environment. In contrast to previous works which require hundreds of measurements, this is the first cache side-channel attack on a real system that can recover AES keys with a minimal number of measurements. We can successfully recover AES keys from T-Table based implementations with as few as ten measurements.Comment: Accepted at Conference on Cryptographic Hardware and Embedded Systems (CHES '17

The 3D Grazing Collision of Two Black Holes

We present results for two colliding black holes (BHs), with angular momentum, spin, and unequal mass. For the first time gravitational waveforms are computed for a grazing collision from a full 3D numerical evolution. The collision can be followed through the merger to form a single BH, and through part of the ringdown period of the final BH. The apparent horizon is tracked and studied, and physical parameters, such as the mass of the final BH, are computed. The total energy radiated in gravitational waves is shown to be consistent with the total mass of the spacetime and the final BH mass. The implication of these simulations for gravitational wave astronomy is discussed.Comment: 4 pages, 7 figures, revte

Implementing a 48 h EWTD-compliant rota for junior doctors in the UK does not compromise patients’ safety : assessor-blind pilot comparison

Background: There are currently no field data about the effect of implementing European Working Time Directive (EWTD)-compliant rotas in a medical setting. Surveys of doctors’ subjective opinions on shift work have not provided reliable objective data with which to evaluate its efficacy. Aim: We therefore studied the effects on patient's safety and doctors’ work-sleep patterns of implementing an EWTD-compliant 48 h work week in a single-blind intervention study carried out over a 12-week period at the University Hospitals Coventry & Warwickshire NHS Trust. We hypothesized that medical error rates would be reduced following the new rota. Methods: Nineteen junior doctors, nine studied while working an intervention schedule of <48 h per week and 10 studied while working traditional weeks of <56 h scheduled hours in medical wards. Work hours and sleep duration were recorded daily. Rate of medical errors (per 1000 patient-days), identified using an established active surveillance methodology, were compared for the Intervention and Traditional wards. Two senior physicians blinded to rota independently rated all suspected errors. Results: Average scheduled work hours were significantly lower on the intervention schedule [43.2 (SD 7.7) (range 26.0–60.0) vs. 52.4 (11.2) (30.0–77.0) h/week; P < 0.001], and there was a non-significant trend for increased total sleep time per day [7.26 (0.36) vs. 6.75 (0.40) h; P = 0.095]. During a total of 4782 patient-days involving 481 admissions, 32.7% fewer total medical errors occurred during the intervention than during the traditional rota (27.6 vs. 41.0 per 1000 patient-days, P = 0.006), including 82.6% fewer intercepted potential adverse events (1.2 vs. 6.9 per 1000 patient-days, P = 0.002) and 31.4% fewer non-intercepted potential adverse events (16.6 vs. 24.2 per 1000 patient-days, P = 0.067). Doctors reported worse educational opportunities on the intervention rota. Conclusions: Whilst concerns remain regarding reduced educational opportunities, our study supports the hypothesis that a 48 h work week coupled with targeted efforts to improve sleep hygiene improves patient safety

Randomised comparison of the effectiveness of the laryngeal mask airway supreme, i-gel and current practice in the initial airway management of out of hospital cardiac arrest: A feasibility study

© 2016 The Author. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. Background: The best initial approach to advanced airway management during out of hospital cardiac arrest (OHCA) is unknown. The traditional role of tracheal intubation has been challenged by the introduction of supraglottic airway devices (SGAs), but there is contradictory evidence from observational studies. We assessed the feasibility of a cluster-randomized trial to compare the i-gel SGA vs the laryngeal mask airway supreme (LMAS) vs current practice during OHCA. Methods: We conducted a cluster-randomized trial in a single ambulance service in England, with individual paramedics as the unit of randomization. Consenting paramedics were randomized to use either the i-gel or the LMAS or usual practice for all patients with non-traumatic adult OHCA, that they attended over a 12-month period. The primary outcome was study feasibility, including paramedic and patient recruitment and protocol adherence. Secondary outcomes included survival to hospital discharge and 90 days. Results: Of the 535 paramedics approached, 184 consented and 171 attended study training. Each paramedic attended between 0 and 11 patients (median 3; interquartile range 2-5). We recruited 615 patients at a constant rate, although the LMAS arm was suspended in the final two months following three adverse incidents. The study protocol was adhered to in 80% of patients. Patient characteristics were similar in the three study arms, and there were no differences in secondary outcomes. Conclusions: We have shown that a prospective trial of alternative airway management strategies in OHCA, cluster randomized by paramedic, is feasible

PAin SoluTions In the Emergency Setting (PASTIES)--patient controlled analgesia versus routine care in emergency department patients with non-traumatic abdominal pain: randomised trial

© Smith et al 2015. OBJECTIVE: To determine whether patient controlled analgesia (PCA) is better than routine care in providing effective analgesia for patients presenting to emergency departments with moderate to severe non-traumatic abdominal pain.DESIGN: Pragmatic, multicentre, parallel group, randomised controlled trialSETTING: Five English hospitals.PARTICIPANTS: 200 adults (66% (n=130) female), aged 18 to 75 years, who presented to the emergency department requiring intravenous opioid analgesia for the treatment of moderate to severe non-traumatic abdominal pain and were expected to be admitted to hospital for at least 12 hours.INTERVENTIONS: Patient controlled analgesia or nurse titrated analgesia (treatment as usual).MAIN OUTCOME MEASURES: The primary outcome was total pain experienced over the 12 hour study period, derived by standardised area under the curve (scaled from 0 to 100) of each participant's hourly pain scores, captured using a visual analogue scale. Pre-specified secondary outcomes included total morphine use, percentage of study period in moderate or severe pain, percentage of study period asleep, length of hospital stay, and satisfaction with pain management.RESULTS: 196 participants were included in the primary analyses (99 allocated to PCA and 97 to treatment as usual). Mean total pain experienced was 35.3 (SD 25.8) in the PCA group compared with 47.3 (24.7) in the treatment as usual group. The adjusted between group difference was 6.3 (95% confidence interval 0.7 to 11.9). Participants in the PCA group received significantly more morphine (mean 36.1 (SD 22.4) v 23.6 (13.1) mg; mean difference 12.3 (95% confidence interval 7.2 to 17.4) mg), spent less of the study period in moderate or severe pain (32.6% v 46.9%; mean difference 14.5% (5.6% to 23.5%)), and were more likely to be perfectly or very satisfied with the management of their pain (83% (73/88) v 66% (57/87); adjusted odds ratio 2.56 (1.25 to 5.23)) in comparison with participants in the treatment as usual group.CONCLUSIONS: Significant reductions in pain can be achieved by PCA compared with treatment as usual in patients presenting to the emergency department with non-traumatic abdominal pain. Trial registration European Clinical Trials Database EudraCT2011-000194-31; Current Controlled Trials ISRCTN25343280