380 research outputs found

    White-Box AES Implementation Revisited

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    White-box cryptography is an obfuscation technique for protecting secret keys in software implementations even if an adversary has full access to the implementation of the encryption algorithm and full control over its execution platforms. This concept was presented by Chow et al. with white-box implementations of DES and AES in 2002. The strategy used in the implementations has become a design principle for subsequent white-box implementations. However, despite its practical importance, progress has not been substantial. In fact, it is repeated that as a proposal for a white-box implementation is reported, an attack of lower complexity is soon announced. This is mainly because most cryptanalytic methods target specific implementations, and there is no general attack tool for white-box cryptography. In this paper, we present an analytic toolbox on white-box implementations in this design framework and show how to reveal the secret information obfuscated in the implementation using this. For a substitution-linear transformation cipher on nn bits with S-boxes on mm bits, if mQm_Q-bit nonlinear encodings are used to obfuscate output values in the implementation, our attack tool can remove the nonlinear encodings with complexity O(nmQ23mQ)O(\frac{n}{m_Q}2^{3m_Q}). We should increase mQm_Q to obtain higher security, but it yields exponential storage blowing up and so there are limits to increase the security using the nonlinear encoding. If the inverse of the encoded round function FF on nn bits is given, the affine encoding AA can be recovered in O(nmmA323m)O(\frac{n}{m}\cdot{m_A}^32^{3m}) time using our specialized affine equivalence algorithm, where mAm_A is the smallest integer pp such that AA (or its similar matrix obtained by permuting rows and columns) is a block-diagonal matrix with p×pp\times p matrix blocks. According to our toolbox, a white-box implementation in the Chow et al.\u27s framework has complexity at most O(min{22mmnm+4,nlogn2n/2})O\left(\min\left\{ \tfrac{2^{2m}}{m}\cdot n^{m+4}, n\log n \cdot 2^{n/2}\right\}\right) within reasonable storage, which is much less than 2n2^n. To overcome this, we introduce an idea that obfuscates two AES-128 ciphers at once with input/output encoding on 256 bits. To reduce storage, we use a sparse unsplit input encoding. As a result, our white-box AES implementation has up to 110-bit security against our toolbox, close to that of the original cipher. More generally, we may consider a white-box implementation on the concatenation of tt ciphertexts to increase security

    Fahr’s Disease With Intracerebral Hemorrhage at the Uncommon Location: A Case Report

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    Fahr’s disease (FD) is a rare neurologic disorder characterized by the symmetric and bilateral intracerebral calcification in a patient. We describe the case of a 65-year-old woman who presented with gait disturbance, abnormal mentality, and visual field defect. The result of a brain computerized tomography showed spontaneous intracranial hemorrhage in the right parieto-occipital area, and also showed the incidence of symmetric and bilateral intracerebral calcification. Moreover, laboratory studies indicated characteristic hypoparathyroidism. This brings us to understand that additionally, one of her sons also presented with similar intracerebral calcification, and was subsequently diagnosed with FD. Thus, her case was consistent with that of a patient experiencing FD. The patient had hypertension, which we now know might have caused the intracerebral hemorrhage. However, this patient’s brain lesions were in uncommon locations for spontaneous intracerebral hemorrhage, and the lesions were noted as occurring away from the identified heavily calcified areas. Thus, it seemed that the massive calcification of cerebral vessels in the basal ganglia, the most common site of intracerebral hemorrhage, might have prevented a hypertensive intracerebral hemorrhage. Eventually, an intracerebral hemorrhage occurred in an uncommon location in the patient’s brain

    Significance of C4d expression in peritubular capillaries concurrent with microvascular inflammation in for-cause biopsies of ABO-incompatible renal allografts

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    Background Pathologic diagnosis of antibody-mediated rejection (ABMR) in ABO-incompatible (ABOi) transplantation patients is often challenging because patients without ABMR are frequently immunopositive for C4d. The aim of this study was to determine whether C4d positivity with microvascular inflammation (MVI), in the absence of any detectable donor-specific antibodies (DSAs) in ABOi patients, could be considered as ABMR. Methods A retrospective study of 214 for-cause biopsies from 126 ABOi kidney transplantation patients was performed. Patients with MVI score of ≥2 and glomerulitis score of ≥1 (n = 62) were divided into three groups: the absolute ABMR group (DSA-positive, C4d-positive or C4d-negative; n = 36), the C4d-positive group (DSA-negative, C4d-positive; n = 22), and the C4d-negative group (DSA-negative, C4d-negative; n = 4). The Banff scores, estimated glomerular filtration rates (eGFRs), and graft failure rates were compared among groups. Results C4d-positive biopsies showed higher glomerulitis, peritubular capillaritis, and MVI scores compared with C4d-negative specimens. The C4d-positive group did not show significant differences in eGFRs and graft survival compared with the absolute ABMR group. Conclusion The results indicate that C4d positivity, MVI score of ≥2, and glomerulitis score of ≥1 in ABOi allograft biopsies may be categorized and treated as ABMR cases

    Effect of rutin from tartary buckwheat sprout on serum glucose-lowering in animal model of type 2 diabetes

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    This study investigates the anti-diabetic effects of rutin from tartary buckwheat sprout in type 2 diabetes mouse model. The rutin content in tartary buckwheat sprout (TBS) is five times higher than that found in common buckwheat sprout (CBS) as evident from high-performance liquid chromatography analysis. Administration of either rutin or TBS ethanolic extract to diabetes mice decreased the serum glucose level significantly. Rutin down-regulated the expression levels of protein-tyrosine phosphatase 1B; negative regulator of insulin pathway, both transcriptionally and translationally in myocyte C2C12 in a dose-dependent manner. In conclusion, rutin can play a critical role in down-regulation of serum glucose level in type 2 diabetes

    Detection of Bartonella henselae DNA by Polymerase Chain Reaction in a Patient with Cat Scratch Disease : A Case Report

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    We report a case of cat scratch disease caused by Bartonella henselae in Korea. A 25-yr-old woman developed left cervical lymphadenopathy with history of contact with a dog. The cervical lymphadenopathy persisted for 1 month and resolved gradually and spontaneously. Serologic test was not done during the acute stage of the disease. Immunofluorescent antibody test performed during the convalescent stage was positive for B. henselae. To confirm B. henselae infection, polymerase chain reaction (PCR) analysis using aspirates of cervical lymph node was performed and the presence of B. henselae DNA was demonstrated. This is the first reported case of cat scratch disease in Korea confirmed by PCR for B. henselae DNA

    Does Rapid Eye Movement Sleep Aggravate Obstructive Sleep Apnea?

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    Objectives. To investigate the apnea-hypopnea index (AHI) according to the sleep stage in more detail after control of posture. Methods. Patients who underwent nocturnal polysomnography between December 2007 and July 2018 were retrospectively evaluated. Inclusion criteria were as follows: age >18 years, sleep efficacy >80%, and patients who underwent polysomnography only in the supine position (100% of the time). Patients were classified into different groups according to the methods: the first, rapid eye movement (REM)-dominant group (AHIREM/AHINREM >2), non-rapid eye movement (NREM)-dominant group (AHINREM/AHIREM >2), and non-dominant group; and the second, light sleep group (AHIN1N2>AHISWS) and slow wave sleep (SWS) group (AHISWS>AHIN1N2). Results. A total of 234 patients (mean age, 47.4±13.9 years) were included in the study. There were 108 patients (46.2%) in the REM-dominant group, 88 (37.6%) in the non-dominant group, and 38 (16.2%) in the NREM-dominant group. The AHI was significantly higher in the NREM-dominant group than in the REM-dominant group (32.9±22.9 events/hr vs. 18.3±9.5 events/hr, respectively). There were improvements in the AHI from stage 1 to SWS in NREM sleep with the highest level in REM sleep. A higher AHISWS than AHIN1N2 was found in 16 of 234 patients (6.8%); however, there were no significant predictors of these unexpected results except AHI. Conclusion. Our results demonstrated the highest AHI during REM sleep stage in total participants after control of posture. However, there were 16.2% of patients showed NREM-dominant pattern (AHINREM/AHIREM >2) and 6.8% of patients showed higher AHISWS than AHIN1N2. Therefore, each group might have a different pathophysiology of obstructive sleep apnea (OSA), and we need to consider this point when we treat the patients with OSA

    Bone-targeting agents in major solid tumour metastases: a multinational cohort study

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    OBJECTIVE: To describe the epidemiology, clinical characteristics and utilisation patterns of bone-targeting agents (BTAs) in patients with bone metastases from breast, prostate and lung cancer. METHODS: This is a multinational retrospective cohort study including patients with three major solid tumours (breast, prostate and lung cancer) and newly initiated on BTAs (ie, denosumab, zoledronic acid and pamidronate). Records were retrieved from nationwide health databases from Hong Kong and Taiwan (HK and TW: 2013–2017) and Korea (KR: 2012–2016). Descriptive analyses included the annual incidence rates of bone metastases and the cumulative incidence curves of BTA initiation. We used Sankey diagrams to visualise the dynamic BTA utilisation patterns. RESULTS: The annual incidence rate of bone metastases ranged from 3.5% to 4.5% in TW, from 9.6% to 10.3% in HK and from 2.9% to 3.8% in KR. We identified 14.1% (5127), 9.3% (883) and 9.4% (4800) of patients with bone metastases newly initiated on BTAs in TW, HK and KR, respectively. The most frequently used BTA in TW (67.1%) and HK (51.9%) was denosumab, while in KR (84.8%) it was zoledronic acid. Sankey diagrams indicated the proportion of patients remaining on denosumab was highest in TW and HK, while it was zoledronic acid in KR. Specifically, in TW, patients who were on bisphosphonates or had discontinued treatment frequently switched to or reinitiated denosumab. CONCLUSIONS: We found the rate of BTA utilisation remained low across all sites and tumour types in recent years. The dynamic utilisation patterns of BTAs provide better understanding of the treatment landscape for future evaluation of associated outcomes of patients

    Genome-edited HEADING DATE 3a knockout enhances leaf production in Perilla frutescens

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    Environmental cues regulate the transition of many plants from vegetative to flowering development. Day length, or photoperiod, is one cue that synchronizes flowering by changing seasons. Consequently, the molecular mechanism of flowering control is prominent in Arabidopsis and rice, where essential genes like FLOWERING LOCUS T (FT) homolog, HEADING DATE 3a (Hd3a), have been connected to flowering regulation. Perilla is a nutrient-rich leaf vegetable, and the flowering mechanism remains largely elusive. We identified flowering-related genes under short-day conditions using RNA sequencing to develop an enhanced leaf production trait using the flowering mechanism in the perilla. Initially, an Hd3a-like gene was cloned from the perilla and defined as PfHd3a. Furthermore, PfHd3a is highly rhythmically expressed in mature leaves under short-day and long-day conditions. Ectopic expression of PfHd3a in Atft-1 mutant plants has been shown to complement Arabidopsis FT function, resulting in early flowering. In addition, our genetic approaches revealed that overexpression of PfHd3a in perilla caused early flowering. In contrast, the CRISPR/Cas9 generated PfHd3a-mutant perilla showed significantly late flowering, resulting in approximately 50% leaf production enhancement compared to the control. Our results suggest that PfHd3a plays a vital role in regulating flowering in the perilla and is a potential target for molecular breeding in the perilla
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