Efficiency Improvements for Encrypt-to-Self

Recent work by Pijnenburg and Poettering (ESORICS'20) explores the novel cryptographic Encrypt-to-Self primitive that is dedicated to use cases of symmetric encryption where encryptor and decryptor coincide. The primitive is envisioned to be useful whenever a memory-bounded computing device is required to encrypt some data with the aim of temporarily depositing it on an untrusted storage device. While the new primitive protects the confidentiality of payloads as much as classic authenticated encryption primitives would do, it provides considerably better authenticity guarantees: Specifically, while classic solutions would completely fail in a context involving user corruptions, if an encrypt-to-self scheme is used to protect the data, all ciphertexts and messages fully remain unforgeable. To instantiate their encrypt-to-self primitive, Pijnenburg et al propose a mode of operation of the compression function of a hash function, with a carefully designed encoding function playing the central role in the serialization of the processed message and associated data. In the present work we revisit the design of this encoding function. Without questioning its adequacy for securely accomplishing the encrypt-to-self job, we improve on it from a technical/implementational perspective by proposing modifications that alleviate certain conditions that would inevitably require implementations to disrespect memory alignment restrictions imposed by the word-wise operation of modern CPUs, ultimately leading to performance penalties. Our main contributions are thus to propose an improved encoding function, to explain why it offers better performance, and to prove that it provides as much security as its predecessor. We finally report on our open-source implementation of the encrypt-to-self primitive based on the new encoding function.Comment: this is the full version of content that appears at CYSARM'2

Encrypt-to-self:Securely outsourcing storage

We put forward a symmetric encryption primitive tailored towards a specific application: outsourced storage. The setting assumes a memory-bounded computing device that inflates the amount of volatile or permanent memory available to it by letting other (untrusted) devices hold encryptions of information that they return on request. For instance, web servers typically hold for each of the client connections they manage a multitude of data, ranging from user preferences to technical information like database credentials. If the amount of data per session is considerable, busy servers sooner or later run out of memory. One admissible solution to this is to let the server encrypt the session data to itself and to let the client store the ciphertext, with the agreement that the client reproduce the ciphertext in each subsequent request (e.g., via a cookie) so that the session data can be recovered when required. In this article we develop the cryptographic mechanism that should be used to achieve confidential and authentic data storage in the encrypt-to-self setting, i.e., where encryptor and decryptor coincide and constitute the only entity holding keys. We argue that standard authenticated encryption represents only a suboptimal solution for preserving confidentiality, as much as message authentication codes are suboptimal for preserving authenticity. The crucial observation is that such schemes instantaneously give up on all security promises the moment the key is compromised. In contrast, data protected with our new primitive remains fully integrity protected and unmalleable. In the course of this paper we develop a formal model for encrypt-to-self systems, show that it solves the outsourced storage problem, propose surprisingly efficient provably secure constructions, and report on our implementations

Bronchiectasis in children after renal or liver transplantation: A report of five cases

More effective immunosuppressive treatment in children following organ transplantation has significantly improved the survival of the grafts. Therefore, quality of life, long-term prognosis and adverse drug reactions have become more important. One of the main complications of immunosuppressive drugs is infections of the respiratory tract, but irreversible damage to the airways has not been described after renal or liver transplantation. Five children following transplantation of kidney or liver were referred to the Paediatric Pulmonology department because of chronic respiratory complaints. Pulmonary function tests and HRCT scan were performed as routine patient care. Four children with a renal transplant and one with a liver transplant showed chronic bronchitis and moderate to severe airways obstruction. HRCT showed bronchiectasis in all of them. We speculate that the immunosuppressive treatment (in) directly contributes to irreversible airway damage. We recommend including follow-up of lung function in the post-transplantation protocol and considering bronchiectasis in case of respiratory symptoms, to try preventing further damage to the lung

Gray matter network differences between behavioral variant frontotemporal dementia and Alzheimer's disease

We set out to study whether single-subject gray matter (GM) networks show disturbances that are specific for Alzheimer's disease (AD; n = 90) or behavioral variant frontotemporal dementia (bvFTD; n = 59), and whether such disturbances would be related to cognitive deficits measured with mini-mental state examination and a neuropsychological battery, using subjective cognitive decline subjects as reference. AD and bvFTD patients had a lower degree, connectivity density, clustering, path length, betweenness centrality, and small world values compared with subjective cognitive decline. AD patients had a lower connectivity density than bvFTD patients (F = 5.79, p = 0.02; mean ± standard deviation bvFTD 16.10 ± 1.19%; mean ± standard deviation AD 15.64 ± 1.02%). Lasso logistic regression showed that connectivity differences between bvFTD and AD were specific to 23 anatomical areas, in terms of local GM volume, degree, and clustering. Lower clustering values and lower degree values were specifically associated with worse mini-mental state examination scores and lower performance on the neuropsychological tests. GM showed disease-specific alterations, when comparing bvFTD with AD patients, and these alterations were associated with cognitive deficits

Oxygen saturation targets for children with respiratory distress:a systematic review

BACKGROUND: In children with respiratory distress, supplemental oxygen is indicated at peripheral oxygen saturation ( S pO 2 ) thresholds of 90-94%. However, these thresholds are poorly studied. We conducted a systematic review to summarise the existing evidence for S pO 2 thresholds in children with respiratory distress. METHODS: Electronic databases and registries were searched for original articles published from 1 January 2010 to 7 January 2022 comparing two or more S pO 2 thresholds in children with respiratory distress. Primary outcomes were safety, including mortality, neurocognitive outcomes and readmissions, and effectiveness, including admission rate and length of hospital stay. Methodological appraisal was performed using the Cochrane Risk of Bias 2 (RoB-2) or Risk of Bias in Non-Randomized Studies - of Interventions (ROBINS-I) tools. Results were narratively synthesised. RESULTS: We retrieved 3384 results; seven studies were included. Lower thresholds ranged from 80% to 92% and were compared with higher thresholds ranging from 92% to 94%. Studies were highly heterogeneous in setting, design, population and outcomes. Risk of bias varied from low to high. Lower S pO 2 thresholds had equivalent mortality, neurocognitive outcomes and readmissions or re-attendance to healthcare to higher thresholds. Lower S pO 2 thresholds showed a significant decrease in admission rates by up to 40% and shortened hospitalisation duration by 10-18 h. CONCLUSIONS: The current S pO 2 thresholds of 90-94% in children with respiratory distress may be too high, which could lead to unnecessary hospitalisations and prolonged hospitalisation duration. S pO 2 thresholds as low as 88% are potentially safe in children with respiratory distress and may reduce hospitalisation rates and length of stay. However, high-quality evidence is needed to support this. </p

Antisense Oligonucleotides Promote Exon Inclusion and Correct the Common c.-32-13T>G GAA Splicing Variant in Pompe Disease

The most common variant causing Pompe disease is c.-32-13T>G (IVS1) in the acid α-glucosidase (GAA) gene, which weakens the splice acceptor of GAA exon 2 and induces partial and complete exon 2 skipping. It also allows a low level of leaky wild-type splicing, leading to a childhood/adult phenotype. We hypothesized that cis-acting splicing motifs may exist that could be blocked using antisense oligonucleotides (AONs) to promote exon inclusion. To test this, a screen was performed in patient-derived primary fibroblasts using a tiling array of U7 small nuclear RNA (snRNA)-based AONs. This resulted in the identification of a splicing regulatory element in GAA intron 1. We designed phosphorodiamidate morpholino oligomer-based AONs to this element, and these promoted exon 2 inclusion and enhanced GAA enzyme activity to levels above the disease threshold. These results indicate that the common IVS1 GAA splicing variant in Pompe disease is subject to negative regulation, and inhibition of a splicing regulatory element using AONs is able to restore canonical GAA splicing and endogenous GAA enzyme activity

The clinical profile of right temporal lobe atrophy

Frontotemporal lobar degeneration is currently associated with three syndromic variants. Disorders of speech and language figure prominently in two of the three variants, and are associated with left-sided frontotemporal atrophy. The detailed characterization of these syndromes contrasts with the relative paucity of information relating to frontotemporal lobar degeneration primarily affecting the right cerebral hemisphere. The objective of this study was to identify the clinical profile associated with asymmetrical, predominantly right-sided, temporal lobe atrophy. Twenty patients with predominant right temporal lobe atrophy were identified on the basis of blinded visual assessment of the MRI scans. The severity of right temporal lobe atrophy was quantified using volumetric analysis of the whole temporal lobes, the amygdala and the hippocampus. Profiles of cognitive function, behavioural and personality changes were obtained on each patient. The pattern of atrophy and the clinical features were compared with those observed in a group of patients with semantic dementia and predominant left-sided temporal lobe atrophy. The mean right temporal lobe volume in the right temporal lobe atrophy group was reduced by 37%, with the mean left temporal lobe volume reduced by 19%. There was marked atrophy of the right hippocampus and right amygdala, with mean volumes reduced by 41 and 51%, respectively (left hippocampus and amygdala volumes were reduced by 18 and 33%, respectively). The most prominent cognitive deficits were impairment of episodic memory and getting lost. Prosopagnosia was a symptom in right temporal lobe atrophy patients. These patients also exhibited a variety of behavioural symptoms including social disinhibition, depression and aggressive behaviour. Nearly all behavioural disorders were more prevalent in the right temporal lobe atrophy patient group than the semantic dementia group. Symptoms particular to the right temporal lobe atrophy patient group included hyper-religiosity, visual hallucinations and cross-modal sensory experiences. The combination of clinical features associated with predominant right temporal lobe atrophy differs significantly from those associated with the other syndromes associated with focal degeneration of the frontal and temporal lobes and it is, therefore, proposed that this right temporal variant should be considered a separate syndromic variant of frontotemporal lobar degeneration

Художній світ Василя Стуса

В статье рассматривается жизненный и творческий путь Василия Стуса, который за непокорность, за своё личное мнение, за гордость провёл долгие годы в ссылке. Исследования проводятся на архивных материалах, воспоминаниях современников поэта. Рассматривается следующая проблема: определить роль и место творческого наследия Василия Стуса в развитии украинской культуры. Цель: раскрыть идейно-художественные тенденции поэзии В.Стуса, подчеркнуть его обширный словарь.Дана стаття присвячена життєвій та творчій стежині Василя Стуса, який за нескореність, за непокірність, за свою власну думку, за гордість, за неприниження зазнав довгих років заслання. Дослідження проводиться на архівних матеріалах, спогадах сучасників поета. Розв’язується така проблема: визначити роль і місце творчого доробку В.Стуса у розвитку української культури. Мета: розкрити ідейно-художні особливості поезій В.Стуса, підкреслити його надзвичайно широкий словник.The article deals with Vasyl Stys’ life and creative way why speut many years in exile for his disobeying and own way of thinking. The investigation helds upon archive materials, recollections of the poet’s contemporaries. Defining the position and the place of creative heredity of Vasyl Stys is under the problem stated. Setting out the ideal and exressive tendencies of V.Stys’ poetry, underlying of his vast verbal stock is a main goa