31 research outputs found
Fully Abstract and Robust Compilation and How to Reconcile the Two, Abstractly
The most prominent formal criterion for secure compilation is full
abstraction, the preservation and reflection of contextual equivalence. Recent
work introduced robust compilation, defined as the preservation of robust
satisfaction of hyperproperties, i.e., their satisfaction against arbitrary
attackers. In this paper, we initially set out to compare these two approaches
to secure compilation. To that end, we provide an exact description of the
hyperproperties that are robustly satisfied by programs compiled with a fully
abstract compiler, and show that they can be meaningless or trivial. We then
propose a novel criterion for secure compilation formulated in the framework of
Mathematical Operational Semantics (MOS), guaranteeing both full abstraction
and the preservation of robust satisfaction of hyperproperties in a more
sensible manner
Eosinophilic gastroenteritis: a case report and review of the literature
BackgroundEosinophilic gastroenteritis (EoG) is a rare disease of unknown etiology characterized by patchy or diffuse eosinophilic infiltration of the gastrointestinal tract wall. As clinical presentation and endoscopic/ radiological findings are nonspecific, diagnosis may only be ascertained by histologic findings.Clinical case This article presents a case of EoG with associated colonic involvement but without peripheral eosinophilia. Although no allergy could be demonstrated, the clinical symptoms and histologic pattern of diffuse eosinophilic mucosal infiltration disappeared after steroid therapy, as discovered by a careful endoscopic follow-up.Discussion Current concepts of this complex disorder and a review of the literature are presented
Journey Beyond Full Abstraction: Exploring Robust Property Preservation for Secure Compilation
—Good programming languages provide helpful abstractions for writing secure code, but the security properties of
the source language are generally not preserved when compiling a
program and linking it with adversarial code in a low-level target
language (e.g., a library or a legacy application). Linked target
code that is compromised or malicious may, for instance, read and
write the compiled program’s data and code, jump to arbitrary
memory locations, or smash the stack, blatantly violating any
source-level abstraction. By contrast, a fully abstract compilation
chain protects source-level abstractions all the way down, ensuring that linked adversarial target code cannot observe more about
the compiled program than what some linked source code could
about the source program. However, while research in this area
has so far focused on preserving observational equivalence, as
needed for achieving full abstraction, there is a much larger space
of security properties one can choose to preserve against linked
adversarial code. And the precise class of security properties one
chooses crucially impacts not only the supported security goals
and the strength of the attacker model, but also the kind of
protections a secure compilation chain has to introduce.
We are the first to thoroughly explore a large space of formal
secure compilation criteria based on robust property preservation, i.e., the preservation of properties satisfied against arbitrary
adversarial contexts. We study robustly preserving various classes
of trace properties such as safety, of hyperproperties such as
noninterference, and of relational hyperproperties such as trace
equivalence. This leads to many new secure compilation criteria,
some of which are easier to practically achieve and prove than
full abstraction, and some of which provide strictly stronger
security guarantees. For each of the studied criteria we propose an equivalent “property-free” characterization that clarifies
which proof techniques apply. For relational properties and
hyperproperties, which relate the behaviors of multiple programs,
our formal definitions of the property classes themselves are
novel. We order our criteria by their relative strength and show
several collapses and separation results. Finally, we adapt existing
proof techniques to show that even the strongest of our secure
compilation criteria, the robust preservation of all relational
hyperproperties, is achievable for a simple translation from a
statically typed to a dynamically typed language
Trace-Relating Compiler Correctness and Secure Compilation
Compiler correctness is, in its simplest form, defined as the inclusion of
the set of traces of the compiled program into the set of traces of the
original program, which is equivalent to the preservation of all trace
properties. Here traces collect, for instance, the externally observable events
of each execution. This definition requires, however, the set of traces of the
source and target languages to be exactly the same, which is not the case when
the languages are far apart or when observations are fine-grained. To overcome
this issue, we study a generalized compiler correctness definition, which uses
source and target traces drawn from potentially different sets and connected by
an arbitrary relation. We set out to understand what guarantees this
generalized compiler correctness definition gives us when instantiated with a
non-trivial relation on traces. When this trace relation is not equality, it is
no longer possible to preserve the trace properties of the source program
unchanged. Instead, we provide a generic characterization of the target trace
property ensured by correctly compiling a program that satisfies a given source
property, and dually, of the source trace property one is required to show in
order to obtain a certain target property for the compiled code. We show that
this view on compiler correctness can naturally account for undefined behavior,
resource exhaustion, different source and target values, side-channels, and
various abstraction mismatches. Finally, we show that the same generalization
also applies to many secure compilation definitions, which characterize the
protection of a compiled program against linked adversarial code.Comment: ESOP'20 camera ready version together with online appendi
A Novel Vasoactive Peptide “PG1” from Buffalo Ice-Cream Protects from Angiotensin-Evoked High Blood Pressure
Arterial hypertension is the most important risk factor for cardiovascular diseases, myocardial infarction, heart failure, renal failure and peripheral vascular disease. In the last decade, milk-derived bioactive peptides have attracted attention for their beneficial cardiovascular properties. Methods: Here, we combined in vitro chemical assay such as LC-MS/MS analysis of buffalo ice cream, ex vivo vascular studies evaluating endothelial and smooth muscle responses using pressure myograph, and translational assay testing in vivo the vascular actions of PG1 administration in murine models. Results: We demonstrate that a novel buffalo ice-cream-derived pentapeptide “QKEPM”, namely PG1, is a stable peptide that can be obtained at higher concentration after gastro-intestinal digestions (GID) of buffalo ice-cream (BIC). It owns potent vascular effect in counteract the effects of angiotensin II-evoked vasoconstriction and high blood pressure levels. Its effects are mediated by the inhibitory effect on AT1 receptor leading to a downregulation of p-ERK½/Rac1-GTP and consequent reduction of oxidative stress. Conclusions: These results strongly candidate PG1, as a novel bioactive peptide for the prevention and management of hypertension, thus expanding the armamentarium of preventive strategies aimed at reducing the incidence and progression of hypertension and its related cardiovascular complication
SSProve: A Foundational Framework for Modular Cryptographic Proofs in Coq
State-separating proofs (SSP) is a recent methodology for structuring game-based cryptographic proofs in a modular way, by using algebraic laws to exploit the modular structure of composed protocols. While promising, this methodology was previously not fully formalized and came with little tool support. We address this by introducing SSProve, the first general verification framework for machine-checked state-separating proofs. SSProve combines high-level modular proofs about composed protocols, as proposed in SSP, with a probabilistic relational program logic for formalizing the lower-level details, which together enable constructing machine-checked cryptographic proofs in the Coq proof assistant. Moreover, SSProve is itself fully formalized in Coq, including the algebraic laws of SSP, the soundness of the program logic, and the connection between these two verification styles.
To illustrate SSProve we use it to mechanize the simple security proofs of ElGamal and PRF-based encryption. We also validate the SSProve approach by conducting two more substantial case studies: First, we mechanize an SSP security proof of the KEM-DEM public key encryption scheme, which led to the discovery of an error in the original paper proof that has since been fixed. Second, we use SSProve to formally prove security of the sigma-protocol zero-knowledge construction, and we moreover construct a commitment scheme from a sigma-protocol to compare with a similar development in CryptHOL. We instantiate the security proof for sigma-protocols to give concrete security bounds for Schnorr\u27s sigma-protocol
The Association of PNPLA3 Variants with Liver Enzymes in Childhood Obesity Is Driven by the Interaction with Abdominal Fat
BACKGROUND AND AIMS: A polymorphism in adiponutrin/patatin-like phospholipase-3 gene (PNPLA3), rs738409 C->G, encoding for the I148M variant, is the strongest genetic determinant of liver fat and ALT levels in adulthood and childhood obesity. Aims of this study were i) to analyse in a large group of obese children the role of the interaction of not-genetic factors such as BMI, waist circumference (W/Hr) and insulin resistance (HOMA-IR) in exposing the association between the I148M polymorphism and ALT levels and ii) to stratify the individual risk of these children to have liver injury on the basis of this gene-environment interaction. METHODS: 1048 Italian obese children were investigated. Anthropometric, clinical and metabolic data were collected and the PNPLA3 I148M variant genotyped. RESULTS: Children carrying the 148M allele showed higher ALT and AST levels (p = 0.000006 and p = 0.0002, respectively). Relationships between BMI-SDS, HOMA-IR and W/Hr with ALT were analysed in function of the different PNPLA3 genotypes. Children 148M homozygous showed a stronger correlation between ALT and W/Hr than those carrying the other genotypes (p: 0.0045) and, therefore, 148M homozygotes with high extent of abdominal fat (W/Hr above 0.62) had the highest OR (4.9, 95% C. I. 3.2-7.8, p = 0.00001) to develop pathologic ALT. CONCLUSIONS: We have i) showed for the first time that the magnitude of the association of PNPLA3 with liver enzymes is driven by the size of abdominal fat and ii) stratified the individual risk to develop liver damage on the basis of the interaction between the PNPLA3 genotype and abdominal fat
A formal framework for correct and secure compilation
Wir untersuchen einen eine große Auswahl von korrekter und sicherer Kompilierungsdefinitionen, die abhängen von der Klasse von Trace-Eigenschaften (Prädikaten für Ausführungstracing), Hypereigenschaften (Prädikaten für Sätze von Ausführungstracing) und relationalen Hypereigenschaften (Prädikaten für Sätze von Tupeln von Ausführungstracing und Sätze von Ausführungstracing), die von Quellprogrammen erfüllt oder robuste erfüllt werden. Jedes von unsere Kriterium ist in viele gleichwertig Formulierungen: einer von ihnen ist besser geeignet für die Überprüfung der Übersetzungskette, das andere beschreiben explizit, welche Eigenschaften durch die Kompilierung erhalten bleiben. Wir bieten an einen Vergleich unseren Kriterien sowohl untereinander als auch mit dem Full Abstraction Kriterium
Telerilevamento iperspettrale e termografico integrato per la focalizzazione di anomalie riconducibili a materiali sepolti
3-Hydroxytyrosol Promotes Angiogenesis In Vitro by Stimulating Endothelial Cell Migration
Cardiovascular diseases, followed by strokes, represent the leading cause of mortality worldwide. Despite its success in preventing cardiovascular diseases, the therapeutic potential of 3-Hydroxytyrosol (HT) for treating ischemic diseases is yet to be investigated in detail, especially with regard to ischemic heart disease, which is a major challenge for humans. We assessed that low concentrations (1–5 µM) of HT, generally achieved after the ingestion of olive oil, stimulate endothelial cells migration and angiogenesis in an in vitro model. At early time points (1–6 h), HT induces the expression of different proteins such as proto-oncogene tyrosine-protein kinase Src (Src), rho-associated protein kinase (ROCK) and matrix metalloproteinase-2 (MMP-2) protein influencing cell adhesion, cytoskeletal dynamics and cell migration. We observed that at the same time, HT induces prominent vascular formation in the tube formation assay, accompanied by an increase in the expression of the vascular endothelial growth factor receptor (VEGF-R2) and PI3K-Akt-eNOS protein pathways, which are recognized for their central role in angiogenesis. Therefore, in addition to the proven capability of HT to regulate reactive oxygen species (ROS) levels, through both direct scavenging properties and indirect antioxidant efficacy, our results revealed that HT promotes angiogenesis, arguing in favor of great pharma-nutritional potential in ischemic injuries