A large study on the effect of code obfuscation on the quality of java code

Context: Obfuscation is a common technique used to protect software against malicious reverse engineering. Obfuscators manipulate the source code to make it harder to analyze and more difficult to understand for the attacker. Although different obfuscation algorithms and implementations are available, they have never been directly compared in a large scale study. Aim: This paper aims at evaluating and quantifying the effect of several different obfuscation implementations (both open source and commercial), to help developers and project managers to decide which algorithms to use. Method: In this study we applied 44 obfuscations to 18 subject applications covering a total of 4 millions lines of code. The effectiveness of these source code obfuscations has been measured using 10 code metrics, considering modularity, size and complexity of code. Results: Results show that some of the considered obfuscations are effective in making code metrics change substantially from original to obfuscated code, although this change (called potency of the obfuscation) is different on different metrics. In the paper we recommend which obfuscations to select, given the security requirements of the software to be protected

Uma perspectiva naturalista do usuário de design

Este estudo reúne uma série de informações sobre design centrado no usuário e naturalismo. Através da compilação e análise de dados bibliográficos, breves conhecimentos sobre cada tema foram relacionados com o intuito de apresentar uma perspectiva naturalista do usuário de produtos de design. O método de pesquisa utilizado foi a investigação bibliográfica, que abrange as áreas de design, design centrado no usuário e naturalismo filosófico. Exemplificando as relações entre essas áreas, alguns conhecimentos obtidos pela neurociência fornecem uma perspectiva naturalista do usuário de design, de modo a mostrar como fatores biológicos podem influenciar sua interação com objetos de design.Abstract: This study collects a range of information about user-centered design and naturalism. Through the compilation and analysis of bibliographic data, brief knowledge of each theme were related to present a naturalistic perspective of the user of design products. The research method employed was a bibliographic search, covering the areas of design, user-centered design and philosophical naturalism. Exemplifying the relations between these areas, some knowledge from neuroscience provide a naturalistic perspective of the user of design products, in order to show how biological factors influence his interaction with design objects

Deep Reinforcement Learning for Black-box Testing of Android Apps

The state space of Android apps is huge, and its thorough exploration during testing remains a significant challenge. The best exploration strategy is highly dependent on the features of the app under test. Reinforcement Learning (RL) is a machine learning technique that learns the optimal strategy to solve a task by trial and error, guided by positive or negative reward, rather than explicit supervision. Deep RL is a recent extension of RL that takes advantage of the learning capabilities of neural networks. Such capabilities make Deep RL suitable for complex exploration spaces such as one of Android apps. However, state-of-the-art, publicly available tools only support basic, Tabular RL. We have developed ARES, a Deep RL approach for black-box testing of Android apps. Experimental results show that it achieves higher coverage and fault revelation than the baselines, including state-of-the-art tools, such as TimeMachine and Q-Testing. We also investigated the reasons behind such performance qualitatively, and we have identified the key features of Android apps that make Deep RL particularly effective on them to be the presence of chained and blocking activities. Moreover, we have developed FATE to fine-tune the hyperparameters of Deep RL algorithms on simulated apps, since it is computationally expensive to carry it out on real apps

Evaluation of dynamic explicit mpm formulations for unsaturated soils

Many applications in geohazards prevention involve large deformations of unsaturated soils, e.g. rainfall induced landslides, embankment collapses due to wetting etc. These phenomena can be investigated with multiphase implementations of the Material Point Method (MPM) able to account for the behaviour of unsaturated soils. This paper compares two formulations: (i) afully coupled three-phase formulation(3P)in which the governing equations are derived from the momentum balance and the mass balance equations of solid, liquid and gas phase assuming non-zero gas pressure,the primary unknowns are the absolute accelerationsof the phases (aS–aL–aG formulation); (ii)a simplified approachthatneglectsthe momentum balance equation of the gas(2P_s).Potentialities and limitations of these approaches are highlighted consideringa 1D infiltration problem.Despite the introduced simplifications, the simplified formulation gives reasonably good results in many engineering cases

Role of Estrogen and Estrogen Receptor in GH-Secreting Adenomas

Acromegaly is a rare disease with several systemic complications that may lead to increased overall morbidity and mortality. Despite several available treatments, ranging from transsphenoidal resection of GH-producing adenomas to different medical therapies, complete hormonal control is not achieved in some cases. Some decades ago, estrogens were first used to treat acromegaly, resulting in a significant decrease in IGF1 levels. However, due to the consequent side effects of the high dose utilized, this treatment was later abandoned. The evidence that estrogens are able to blunt GH activity also derives from the evidence that women with GH deficiency taking oral estro-progestins pills need higher doses of GH replacement therapy. In recent years, the role of estrogens and Selective Estrogens Receptor Modulators (SERMs) in acromegaly treatment has been re-evaluated, especially considering poor control of the disease under first- and second-line medical treatment. In this review, we analyze the state of the art concerning the impact of estrogen and SERMs on the GH/IGF1 axis, focusing on molecular pathways and the possible implications for acromegaly treatment

Search Based Clustering for Protecting Software with Diversified Updates

Reverse engineering is usually the stepping stone of a variety of attacks aiming at identifying sensitive information (keys, credentials, data, algorithms) or vulnerabilities and flaws for broader exploitation. Software applications are usually deployed as identical binary code installed on millions of computers, enabling an adversary to develop a generic reverse-engineering strategy that, if working on one code instance, could be applied to crack all the other instances. A solution to mitigate this problem is represented by Software Diversity, which aims at creating several structurally different (but functionally equivalent) binary code versions out of the same source code, so that even if a successful attack can be elaborated for one version, it should not work on a diversified version. In this paper, we address the problem of maximizing software diversity from a search-based optimization point of view. The program to protect is subject to a catalogue of transformations to generate many candidate versions. The problem of selecting the subset of most diversified versions to be deployed is formulated as an optimisation problem, that we tackle with different search heuristics. We show the applicability of this approach on some popular Android apps

Time-resolved nanosecond imaging of the propagation of a corona-like plasma discharge in water at positive applied voltage polarity

International audienceThe present paper is an experimental study of a pulsed filamentary plasma discharge inside liquid water in pin to plane electrode configuration. Time resolved electrical and imaging diagnostics have been performed. The initiation and the propagation of the discharge have been studied for several experimental parameters. The propagation is continuous and is followed by reilluminations at low water conductivity. The measured propagation velocity of the plasma discharge is 30km/s for the secondary positive mode. This velocity was found to be surprisingly constant whatever the experimental parameters and especially as a function of the water conductivity