261 research outputs found
APTE: An Algorithm for Proving Trace Equivalence
This paper presents APTE, a new tool for automatically proving the security of cryptographic protocols. It focuses on proving trace equivalence between processes, which is crucial for specifying privacy type properties such as anonymity and unlinkability.
The tool can handle protocols expressed in a calculus similar to the applied-pi calculus, which allows us to capture most existing protocols that rely on classical cryptographic primitives. In particular, APTE handles private channels and else branches in protocols with bounded number of sessions. Unlike most equivalence verifier tools, APTE is guaranteed to terminate
Moreover, APTE is the only tool that extends the usual notion of trace equivalence by considering ``side-channel'' information leaked to the attacker such as the length of messages and the execution times. We illustrate APTE on different case studies which allowed us to automatically (re)-discover attacks on protocols such as the Private Authentication protocol or the protocols of the electronic passports
Physical inactivity amplifies the negative association between sleep quality and depressive symptoms.
Poor sleep quality and physical inactivity are known risk factors for depressive symptoms. Yet, whether these factors differently contribute to depressive symptoms and whether they interact with one another remains unclear. Here, we examined how sleep quality and physical activity influence depressive symptoms in 79,274 adults 50 years of age or older (52.4% women) from the Survey of Health, Aging and Retirement in Europe (SHARE) study. Sleep quality (poor vs. good), physical activity (inactive vs. active), and depressive symptoms (0 to 12 score) were repeatedly collected (7 waves of data collection) between 2004 and 2017. Results showed that sleep quality and physical activity were associated with depressive symptoms. Specifically, participants with poorer sleep quality reported more depressive symptoms than participants with better sleep quality (b = 1.85, 95% CI = 1.83-1.86, p < .001). Likewise, compared to physically active participants, physically inactive participants reported more depressive symptoms (b = 0.44, 95% CI = 0.42-0.45, p < .001). Moreover, sleep quality and physical activity showed an interactive association with depressive symptoms (b = 0.17, 95% CI = 0.13-0.20, p < .001). The negative association between poor sleep quality and higher depressive symptoms was stronger in physically inactive than active participants. These findings suggest that, in adults 50 years of age or older, both poor sleep quality and physical inactivity are related to an increase in depressive symptoms. Moreover, the detrimental association between poor sleep quality and depressive symptoms is amplified in physically inactive individuals
Search for large missing transverse momentum in association with one top-quark in proton-proton collisions at √s = 13 TeV with the ATLAS detector
This paper describes a search for events with one top-quark and large missing transverse momentum in the final state. Data collected during 2015 and 2016 by the ATLAS experiment from 13 TeV proton–proton collisions at the LHC corresponding to an integrated luminosity of 36.1 fb−1 are used. Two channels are considered, depending on the leptonic or the hadronic decays of the W boson from the top quark. The obtained results are interpreted in the context of simplified models for dark-matter production and for the single production of a vector-like T quark. In the absence of significant deviations from the Standard Model background expectation, 95% confidence-level upper limits on the corresponding production cross-sections are obtained and these limits are translated into constraints on the parameter space of the models considered
Cognitive-bias modification intervention to improve physical activity in patients following a rehabilitation programme:protocol for the randomised controlled IMPACT trial
Psychometric evaluation of the inventory of dimensions of emerging adulthood (IDEA) in China.
BACKGROUND/OBJECTIVE: Emerging adulthood (EA, age range between 18 to 29 years) is an important developmental stage that is characterized by marked social and psychological changes. Currently, its developmental features are quantified by the Inventory of the Dimensions of Emerging Adulthood (IDEA) but a validated Chinese version of this questionnaire (IDEA-C) is lacking. Thus, this research, which consists of two consecutive studies, aimed to investigate the psychometric properties of the translated IDEA in a Chinese sample of emerging adults. METHOD: Firstly, a forward-backward translation of the IDEA-C scale was conducted. Item analysis and exploratory factor analysis were performed in Sample 1a (n = 2438), followed by structural validity test in Sample 1b (n = 2461). Concurrent validity and internal consistency were evaluated in Sample 1(n = 4899). Finally, test-retest reliability was tested in Sample 2 (n = 185). Then, the second study aimed to test the factor structure proposed by study 1 in the non-student sample (n = 2200) by confirmatory factor analysis. In addition, the second study also investigated whether the attainment of college education influenced the EA experience of non-student emerging adults in China. And the association was examined between the socioeconomic status of emerging adults and the subscales of IDEA. RESULTS: In the college sample, the IDEA-C scale presented a four-factor structure different from the original five-factor structure (χ2(190)=1116.84, p 0.77), test-retest reliability (r>0.49, p 0.64) and test-retest reliability (r>0.43, p < 0.01). CONCLUSION: The results of the present study confirmed that the Chinese version of the IDEA is found to be valid for measuring psychological characteristics of EA in Chinese-speaking samples of emerging adults
The hitchhiker's guide to decidability and complexity of equivalence properties in security protocols
International audiencePrivacy-preserving security properties in cryptographic protocols are typically modelled by observational equivalences in process calculi such as the applied pi-calulus. We survey decidability and complexity results for the automated verification of such equivalences, casting existing results in a common framework which allows for a precise comparison. This unified view, beyond providing a clearer insight on the current state of the art, allowed us to identify some variations in the statements of the decision problems-sometimes resulting in different complexity results. Additionally, we prove a couple of novel or strengthened results
Enforcing Privacy in the Presence of Others: Notions, Formalisations and Relations
Protecting privacy against bribery/coercion is a necessary requirement in electronic services, like e-voting, e-auction and e-health. Domain-specific privacy properties have been proposed to capture this. We generalise these properties as enforced privacy: a system enforces a user's privacy even when the user collaborates with the adversary. In addition, we account for the influence of third parties on a user's privacy. Third parties can help to break privacy by collaborating with the adversary, or can help to protect privacy by cooperating with the target user. We propose independency of privacy to capture the negative privacy impact that third parties can have, and coalition privacy to capture their positive privacy impact. We formally define these privacy notions in the applied pi calculus and build a hierarchy showing their relations
When Are Three Voters Enough for Privacy Properties?
International audienceProtocols for secure electronic voting are of increasing societal importance. Proving rigorously their security is more challenging than many other protocols, which aim at authentication or key exchange. One of the reasons is that they need to be secure for an arbitrary number of malicious voters. In this paper we identify a class of voting protocols for which only a small number of agents needs to be considered: if there is an attack on vote privacy then there is also an attack that involves at most 3 voters (2 honest voters and 1 dishonest voter). In the case where the protocol allows a voter to cast several votes and counts, e.g., only the last one, we also reduce the number of ballots required for an attack to 10, and under some additional hypotheses, 7 ballots. Our results are formalised and proven in a symbolic model based on the applied pi calculus. We illustrate the applicability of our results on several case studies, including different versions of Helios and Prêt-` a-Voter, as well as the JCJ protocol. For some of these protocols we can use the ProVerif tool to provide the first formal proofs of privacy for an unbounded number of voters
Communication, development, and social change in Spain: A field between institutionalization and implosion
This paper renders an account of the rapid institutionalization of the academic field of Communication for Development and Social Change (CDCS) in Spain in recent years following a period of neglect and marginalization. The ongoing expansion of the field of CDSC in the Spanish context is understood as a process of implosion, i.e. a collapse inwards, which results from the inconsistencies and weaknesses of fast and late institutionalization. The methodological approach for this inquiry is a documental review of both academic literature and research and institutional reports produced in Spain between 1980 and 2010. Based on this review, the paper contrasts the trajectory of the field in Spain with the debates at the international level, establishing relevant continuities and differences.This article is part of the Research Project (Ministry of Economy and Competitiveness,
Spain) CSO2014-52005-R titled ‘Evaluation and Monitoring of Communication for
Development and Social Change in Spain: design of indicators to measure its social
impact’ (2015–2017)17 página
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