Remote Cache-Timing Attack without Learning Phase

Theoretically secure cryptographic algorithms can be vulnerable to attacks due to their implementation flaws, which disclose side-channel information about the secret key. Bernstein\u27s attack is a well known cache-timing attack which uses execution time as the side-channel. The major drawback of this attack is that it needs an identical target machine to perform its learning phase where the attacker models the cache timing-behavior of the target machine. This assumption makes the attack unrealistic in many circumstances. In this work, we present an effective method to eliminate the learning phase. We propose a methodology to model the cache timing-behavior of the target machine by hypothetical modeling. To test the validity of the proposed method, we performed the Bernstein attack and showed that, in majority of the cases, the new attack is actually superior to the original attack which uses a learning phase

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Cache-timing attacks without a profiling phase

Theoretically secure cryptographic algorithms can be vulnerable to attacks due to their implementation flaws. Bernstein's attack is a well-known cache-timing attack that uses execution times as the side-channel. The major drawback of this attack is that it needs an identical target machine to perform its profiling phase where the attacker models the cache timing-behavior of the target machine. This assumption makes the attack unrealistic in many circumstances. In this work, we present an effective method to eliminate the profiling phase. We propose a methodology to model the cache timing-behavior of the target machine by trying hypothetical cache behaviors exhaustively. Our implementation results show that the proposed nonprofiled Bernstein's attack has comparable (and better in some test instances) performance to the original attack with the profiling phase

An approach for isolating the sources of information leakage exploited in cache-based side-channel attacks

We demonstrate that a certain class of side-channel attacks is feasible due to unintentional cache contentions between code segments in cryptographic applications. These inadvertent contentions should be considered as a flaw in the implementation of cryptographic applications, which necessitates a software analysis framework to identify their primary cause and check the effectiveness of proposed countermeasures. We present an approach to detect code segments in cryptographic applications that are in cache contentions with each other, thus leaking information that can be exploited in side-channel attacks to extract secret keys. To evaluate this approach, we conducted a series of experiments by using the well-known Bernstein's attack. Our results demonstrate, for the first time, that the primary source of exploitable information leakage in the Bernstein's AES server, rendering the attack a success, is the unintentional cache contentions between the parts of the OS kernel that handle network communications and the AES encryption code

A rare case of primary rectal choriocarcinoma and review of the literature

Introduction Primary choriocarcinoma of the colon is an extremely rare neoplasm which has a poor prognosis. Only 18 cases have been previously reported in English medical literature. Here we present a case of primary rectal choriocarcinoma with a good response to chemotherapy and review the literature on this uncommon tumor. Case report A 36-year-old woman presented with abdominal pain and vaginal bleeding. Abdominal magnetic resonance imaging revealed 6.9 x 5.3 x 6.4 cm hypervascular mass posterior to uterus very close to rectum. Beta-human chorionic gonadotropin (beta-hCG) level was markedly elevated. Low anterior resection of the rectum with lymph node dissection and total abdominal hysterectomy with bilateral salpingo-oophorectomy were performed. Pathologic diagnosis was reported as colonic choriocarcinoma with a focal component of adenocarcinoma. Post-operative magnetic resonance imaging detected multiple metastatic lesions throughout the liver. The patient was treated with systemic chemotherapy using bleomycin, etoposide and cisplatin (BEP protocol). After three cycles, beta-hCG level decreased to normal and magnetic resonance imaging showed regression of liver metastasis. However, the patient died of respiratory failure due to bleomycin toxicity and pneumonia accompanied by rapid disease progression. Discussion This is an extremely rare case of primary rectal choriocarcinoma. Due to poor prognosis of the disease, it seems very important to start prompt treatment to improve patient's survival

Local excision versus thrombectomy in thrombosed external hemorrhoids : a multicenter, prospective, observational study

Background: Available guidelines describing the procedural treatment of thrombosed external hemorrhoids (TEH) rely solely on expert opinion. We aimed to compare local excision (LE) and thrombectomy (incision) in terms of treatment success, factors affecting success, and outcomes. Methods: This was a multicenter, prospective, observational study conducted in eight centers from September 2020 to September 2021. A total of 96 patients (58 LE, 38 thrombectomy) were included. Risk factors, demographics and clinical characteristics were recorded. Follow-up studies were scheduled for the 1(st) week, 1(st), 3(rd) and 6(th) months. Surgical success was assessed at 1 month. Hemorrhoidal Disease Symptom Score (HDSS) and Short Health Scale (SHS) were applied at baseline and the 6(th) month. Wexner fecal incontinence score was applied at all follow-up studies. Results: Overall mean age was 41.5 & PLUSMN; 12.7 years. At baseline, groups were similar with regard to demographics and disease severity (HDSS) (p > 0.05 for all). Success was relatively higher in the thrombectomy group (86.8%) compared to the LE group (67.2%) (p = 0.054). Constipation and travel history were significantly associated with lower likelihood of LE success. Symptoms during follow-up were similarly distributed in the groups. Both methods yielded significant improvements in HDSS, SHS and Wexner scores; however, SHS scores (6 months) and Wexner scores (all time points) were significantly better in the thrombectomy group. Conclusion: The in-office thrombectomy procedure may have better short-term outcomes compared to LE in terms of relative success, recurrence and quality of life-despite the fact that success rates were statistically similar with the two interventions. LE may yield particularly worse results in patients with constipation and travel history; thus, thrombectomy appears to be especially advantageous in these patient subsets

Local excision versus thrombectomy in thrombosed external hemorrhoids: a multicenter, prospective, observational study

Abstract Background Available guidelines describing the procedural treatment of thrombosed external hemorrhoids (TEH) rely solely on expert opinion. We aimed to compare local excision (LE) and thrombectomy (incision) in terms of treatment success, factors affecting success, and outcomes. Methods This was a multicenter, prospective, observational study conducted in eight centers from September 2020 to September 2021. A total of 96 patients (58 LE, 38 thrombectomy) were included. Risk factors, demographics and clinical characteristics were recorded. Follow-up studies were scheduled for the 1st week, 1st, 3rd and 6th months. Surgical success was assessed at 1 month. Hemorrhoidal Disease Symptom Score (HDSS) and Short Health Scale (SHS) were applied at baseline and the 6th month. Wexner fecal incontinence score was applied at all follow-up studies. Results Overall mean age was 41.5 ± 12.7 years. At baseline, groups were similar with regard to demographics and disease severity (HDSS) (p > 0.05 for all). Success was relatively higher in the thrombectomy group (86.8%) compared to the LE group (67.2%) (p = 0.054). Constipation and travel history were significantly associated with lower likelihood of LE success. Symptoms during follow-up were similarly distributed in the groups. Both methods yielded significant improvements in HDSS, SHS and Wexner scores; however, SHS scores (6 months) and Wexner scores (all time points) were significantly better in the thrombectomy group. Conclusion The in-office thrombectomy procedure may have better short-term outcomes compared to LE in terms of relative success, recurrence and quality of life–despite the fact that success rates were statistically similar with the two interventions. LE may yield particularly worse results in patients with constipation and travel history; thus, thrombectomy appears to be especially advantageous in these patient subsets

30-Day Morbidity and Mortality of Bariatric Surgery During the COVID-19 Pandemic: a Multinational Cohort Study of 7704 Patients from 42 Countries.

BACKGROUND There are data on the safety of cancer surgery and the efficacy of preventive strategies on the prevention of postoperative symptomatic COVID-19 in these patients. But there is little such data for any elective surgery. The main objectives of this study were to examine the safety of bariatric surgery (BS) during the coronavirus disease 2019 (COVID-19) pandemic and to determine the efficacy of perioperative COVID-19 protective strategies on postoperative symptomatic COVID-19 rates. METHODS We conducted an international cohort study to determine all-cause and COVID-19-specific 30-day morbidity and mortality of BS performed between 01/05/2020 and 31/10/2020. RESULTS Four hundred ninety-nine surgeons from 185 centres in 42 countries provided data on 7704 patients. Elective primary BS (n = 7084) was associated with a 30-day morbidity of 6.76% (n = 479) and a 30-day mortality of 0.14% (n = 10). Emergency BS, revisional BS, insulin-treated type 2 diabetes, and untreated obstructive sleep apnoea were associated with increased complications on multivariable analysis. Forty-three patients developed symptomatic COVID-19 postoperatively, with a higher risk in non-whites. Preoperative self-isolation, preoperative testing for SARS-CoV-2, and surgery in institutions not concurrently treating COVID-19 patients did not reduce the incidence of postoperative COVID-19. Postoperative symptomatic COVID-19 was more likely if the surgery was performed during a COVID-19 peak in that country. CONCLUSIONS BS can be performed safely during the COVID-19 pandemic with appropriate perioperative protocols. There was no relationship between preoperative testing for COVID-19 and self-isolation with symptomatic postoperative COVID-19. The risk of postoperative COVID-19 risk was greater in non-whites or if BS was performed during a local peak