Watermarking security: theory and practice

This article proposes a theory of watermarking security based on a cryptanalysis point of view. The main idea is that information about the secret key leaks from the observations, for instance watermarked pieces of content, available to the opponent. Tools from information theory (Shannon's mutual information and Fisher's information matrix) can measure this leakage of information. The security level is then defined as the number of observations the attacker needs to successfully estimate the secret key. This theory is applied to two common watermarking methods: the substitutive scheme and the spread spectrum based techniques. Their security levels are calculated against three kinds of attack. The experimental work illustrates how Blind Source Separation (especially Independent Component Analysis) algorithms help the opponent exploiting this information leakage to disclose the secret carriers in the spread spectrum case. Simulations assess the security levels derived in the theoretical part of the article

Watermarking security part II: practice

This second part focuses on estimation of secret parameters of some practical watermarking techniques. The first part reveals some theoretical bounds of information leakage about secret keys from observations. However, as usual in information theory, nothing has been said about practical algorithms which pirates use in real life application. Whereas Part One deals with the necessary number of observations to disclose secret keys (see definitions of security levels), this part focuses on the complexity or the computing power of practical estimators. Again, we are inspired here by the work of Shannon as in his famous article [15], he has already made a clear cut between the unicity distance and the work of opponents' algorithm. Our experimental work also illustrates how Blind Source Separation (especially Independent Component Analysis) algorithms help the opponent exploiting this information leakage to disclose the secret carriers in the spread spectrum case. Simulations assess the security levels theoretically derived in Part One

Watermarking security part I: theory

This article proposes a theory of watermarking security based on a cryptanalysis point of view. The main idea is that information about the secret key leaks from the observations, for instance watermarked pieces of content, available to the opponent. Tools from information theory (Shannon's mutual information and Fisher's information matrix) can measure this leakage of information. The security level is then defined as the number of observations the attacker needs to successfully estimate the secret key. This theory is applied to common watermarking methods: the substitutive scheme and spread spectrum based techniques. Their security levels are calculated against three kinds of attack

Insertion professionnelle des adultes ayant un trouble autistique ou un syndrome d'Asperger au Québec

Ce mémoire de recherche présente un survol historique de l'insertion professionnelle des adultes ayant un trouble autistique ou un syndrome d'Asperger, et décrit les différentes formes d'emploi adaptées pour ces personnes. Puis, des entretiens semi dirigés sont faits avec les agents à l'insertion professionnelle des centres d'emploi pour personnes handicapées de différentes régions du Québec et des centres de réadaptation en déficience intellectuelle trouble\ud envahissant du développement [CRDITED]. Les entretiens se rapportent aux conditions d'emploi des personnes ayant un trouble autistique ou un syndrome d'Asperger, aux procédures d'insertion professionnelle, à la réceptivité des employeurs potentiels et au nouveau programme du Gouvernement du Québec «Le Pacte pour l'emploi: Le Québec de toutes ses forces» (2008) qui vise principalement à contrer le manque de main d'oeuvre au Québec.\ud Les réalités vécues par les centres d'emploi pour personnes handicapées en ce qui concerne les conditions d'emploi des personnes ayant un trouble autistique ou un syndrome d'Asperger sont assez similaires. Toutefois, le type et le nombre de services offerts ainsi que la fonnation offerte aux agents pour les informer sur le trouble autistique et le syndrome d'Asperger varient d'un centre d'emploi à l'autre, ces pratiques n'étant pas uniformisées. Finalement, les agents des centres d'emploi se questionnent quant à la réelle pertinence et aux retombées du programme «Le Pacte pour l'emploi: Le Québec de toutes ses forces» (2008).\ud ______________________________________________________________________________ \ud MOTS-CLÉS DE L’AUTEUR : insertion professionnelle, trouble autistique, syndrome d'Asperger, adulte autiste, intégration, conditions d'emplo

Les représentations de la famille dans la série Nos étés

Ce mémoire porte sur les représentations de la famille dans la série Nos étés. La série, en tant que fiction télévisée, prend naissance dans l'objet même qu'est la fiction et, dans un sens plus large, dans le contexte de la production télévisée au Québec. Le contenu de l'émission - l'histoire de deux familles durant le XX e siècle - est inspiré de l'histoire du Québec et de ses familles. Nos étés offre un discours sur la famille, à travers ses représentations. La série, écrite et produite par Anne Boyer et Michel d'Astous, constitue un univers clos de quatre saisons, totalisant 29 épisodes. Nous avons soumis à l'analyse de contenu tous les épisodes, en prenant soin de choisir les scènes traitant de la famille. À partir de chaque scène, nous avons construit une fiche regroupant les informations pertinentes à la recherche. Nous avons finalement analysé les résultats obtenus à l'aide de ces fiches. La série Nos étés offre plusieurs représentations de la famille. Nous avons observé plus en détails les liens de filiation, de mariage et de maternité. Les représentations de la famille sont relativement semblables d'une époque à l'autre et elles rendent compte des changements survenus dans la famille au Québec. De façon générale, Nos étés traite du décalage qui aurait existé entre l'atteinte de la famille idéale et l'envie grandissante d'émancipation des femmes dans le Québec du XXe siècle

Pain complaints in a patient with schizophrenia

peer reviewedSchizophrenia is a complex pathology. Its prevalence reaches almost 1 %. Its semiology can be diversified. Sensorial perception can be altered included pain perception. Most of the studies conclude that psychotic patients have a hypoalgesia. It's important to consider this fact to avoid missing potentially grave somatic disease

A Logic and an Interactive Prover for the Computational Post-Quantum Security of Protocols

International audienceWe provide the first mechanized post-quantum sound security protocol proofs. We achieve this by developing PQ-BC, a computational first-order logic that is sound with respect to quantum attackers, and corresponding mechanization support in the form of the PQ-Squirrel prover. Our work builds on the classical BC logic [7] and its mechanization in the Squirrel [5] prover. Our development of PQ-BC requires making the BC logic sound for a single interactive quantum attacker. We implement the PQ-Squirrel prover by modifying Squirrel, relying on the soundness results of PQ-BC and enforcing a set of syntactic conditions; additionally, we provide new tactics for the logic that extend the tool’s scope. Using PQ-Squirrel, we perform several case studies, thereby giving the first mechanical proofs of their computational post-quantum security. These include two generic constructions of KEM based key exchange, two sub-protocols from IKEv1 and IKEv2, and a proposed post-quantum variant of Signal’s X3DH protocol. Additionally, we use PQ-Squirrel to prove that several classical Squirrel case studies are already post-quantum sound

Assessing and addressing sexual concerns in individuals diagnosed with coronary artery disease

Background/Aims Sexual concerns are frequently reported in people diagnosed with coronary artery disease. These concerns may be related to disorders in one or more phases of the sexual response cycle (i.e. desire, arousal and orgasm). Sexual concerns have been linked to anxiety, depressive symptoms and feelings of despair. As such, nurses should have an understanding of the aetiology of sexual concerns in this population and use appropriate assessment and support strategies. Methods This clinical article discusses several key aspects of evidence-based practice to assess and address sexual concerns in people diagnosed with coronary artery disease. Findings Early assessment of biological, psychological and pharmacological causes of sexual concerns should be carried out. Sexual counselling may be offered to meet specific information needs. Adding pharmacological agents and referring to a sex therapist can be considered to effectively address the sexual concerns of people within this population. Conclusions Approaches to sexual assessment, main information needs of patients with coronary artery disease regarding their sexual health, and support strategies are presented

Effect of simulation on cognitive load in health care professionals and students : protocol for a systematic review and meta-analysis

Objective: The objective of this review is to assess the effect of simulation activities and their design features on cognitive load in health care professionals and students. Introduction: Simulation activities are now widely implemented in health care professionals’ education. However, the mechanisms by which simulations and their design features lead to health care professionals’ and students’ learning remains unclear. Still, because of their high interactivity and complexity, simulation activities have the potential to impact the cognitive load of learners. Synthesizing evidence regarding this phenomenon could help simulation educators identify the design features that affect learners’ cognitive load, and explain why some simulation activities are more effective than others. Inclusion criteria: This review will consider experimental and quasi-experimental studies in which the effect of a simulation activity on cognitive load in health care professionals or students from any discipline or level of practice is evaluated. All academic and health settings will be included. Methods: Following the guidelines of the JBI methods for systematic reviews of effectiveness, CINAHL, Embase, ERIC, MEDLINE, PsycINFO, and Web of Science will be searched for studies published in English or French, without a date limit. Retrieved studies will be independently screened for inclusion, then critically appraised for methodological quality by two reviewers using standardized JBI tools. Data extraction will be done independently using adapted tools from JBI. Where possible, data will be pooled using meta-analytical methods

Stream ciphers: A Practical Solution for Efficient Homomorphic-Ciphertext Compression

International audienceIn typical applications of homomorphic encryption, the first step consists for Alice to encrypt some plaintext m under Bob’s public key pk and to send the ciphertext c = HEpk(m) to some third-party evaluator Charlie. This paper specifically considers that first step, i.e. the problem of transmitting c as efficiently as possible from Alice to Charlie. As previously noted, a form of compression is achieved using hybrid encryption. Given a symmetric encryption scheme E, Alice picks a random key k and sends a much smaller ciphertext c′ = (HEpk(k), Ek(m)) that Charlie decompresses homomorphically into the original c using a decryption circuit CE−1 .In this paper, we revisit that paradigm in light of its concrete implemen- tation constraints; in particular E is chosen to be an additive IV-based stream cipher. We investigate the performances offered in this context by Trivium, which belongs to the eSTREAM portfolio, and we also pro- pose a variant with 128-bit security: Kreyvium. We show that Trivium, whose security has been firmly established for over a decade, and the new variant Kreyvium have an excellent performance