published_or_final_version / Urban Studies / Master / Master of Social Sciences

La thèse s'intéresse aux enjeux méthodologiques présents en situation d'enquête de terrain. Les enquêtes qualitatives réalisées dans le cadre de cette recherche visaient à explorer un trouble de santé. L'enquête portant sur le trouble du ballonnement met notamment en avant le jeu interactionnel entre enquêtée et enquêtrice, et fait apparaître les concepts de stigmate et de secret. L'analyse des interactions sociales entre ces deux acteurs invite à percevoir l'enquête comme un processus au sein duquel différentes phases se déclinent et interagissent ensemble. A partir du recrutement jusqu'à la clôture du terrain, les effets de l'enquête sont observés et analysés à travers le double regard de l'enquêtrice et de l'enquêtée. Nous qualifions cette démarche méthodologique d' " observation interactive ", puisant ses fondements au sein de la méthode d'observation participante et de la tradition de l'interactionnisme symbolique. Une réflexion est également menée sur les effets de réciprocité entre l'élaboration de stratégies d'enquête et le déroulement de l'enquête soumise à l'imprévisibilité du terrain.

Šio darbo tikslas – apžvelgti šiuo metu naudojamas klasikines viešojo rakto šifravimo ir skaitmeninio parašo sistemas bei naujos kartos Signcryption kriptosistemą ir atlikti dedikuotos pasirašymo ir šifravimo kriptosistemos efektyvumo palyginimą su pasirašymo arba šifravimo kriptosistemų kompozicija bei pasiūlyti praktinio pritaikymą naujos kartos Signcryption kriptosistemai. Darbe apžvelgtos šios kriptosistemos: 1. RSA (Rivest, Shamir, Adleman) – klasikinė viešojo rakto pasirašymo arba šifravimo kriptosistema, kurios saugumas paremtas didelių skaičių faktorizacijos uždavinio sprendimo sudėtingumu, 2. ElGamalio – klasikinė viešojo rakto pasirašymo arba šifravimo kriptosistema, kurios saugumas paremtas diskretaus logaritmo problemos sprendimo sudėtingumu, 3. Signcryption – naujos kartos viešojo rakto pasirašymo ir šifravimo kriptosistema, realizuota modifikuotos ElGamalio skaitmeninio parašo schemos pagrindu. Minėtos kriptosistemos apžvelgtos teoriškai, sukurta praktinė jų realizacija ir apžvelgti rezultatai bei palygintas jų efektyvumas, kuris apibrėžiamas dviem parametrais: 1. Pranešimo pasirašymo, šifravimo, dešifravimo ir parašo patikrinimo operacijų trukmė, 2. Perduodamos perteklinės informacijos kiekis – pranešimo ilgio padidėjimas atlikus pasirašymo ir šifravimo operacijas. Taip pat apžvelgtos kriptosistemų realizacijoje naudotos papildomos funkcijos bei algoritmai, tokie kaip AES blokiniai šifrai, SHA maišos funkcijų šeima, HMAC kontrolinis parašas bei pasiūlyti du... [toliau žr. visą tekstą] / This submission called “Efficient encryption and digital signature schemes” consists of three parts. I. In Part I theoretical analysis of popular public key cryptosystems RSA (Rivest, Shamir, Adleman) with security based on the large integer factorization problem and ElGamal with security based on the discrete logarithm problem, along with new cryptographic primitive termed as "signcryption" proposed by Y. Zheng which simultaneously fulfills both the functions of digital signature and public key encryption in a logically single step, and with a cost significantly smaller than that required by "signature followed by encryption" using popular public key cryptosystem composition is done. For the completeness of analysis description of supplemental algorithms and functions such as AES block cipher, SHA hash functions, HMAC keyed hash function is present. II. In Part II the results of the practical implementation done in Python programming language are analyzed. Effectiveness is described by two factors: 1. Total computation time of signing – encryption – decryption – verification operations; 2. Communication overhead – signed and encrypted message length increase compared to the original plaintext. III. In Part III two effective Signcryption implementation algorithms are proposed: secret sharing without threshold and (k, n) threshold schemes. Results of analysis prove Signcryption being secure and extremely effective signature and encryption cryptosystem. It has very low... [to full text]

This thesis considers the problem of finitely iterated rational secret sharing. We describe how to evaluate this problem using game theory and finitely iterated prisoner’s dilemma. The players each have a private horizon that the other player does not know. The only thing that a player knows about their opponent’s private horizon is a common upper bound. The description of a synchronous and asynchronous finitely iterated secret sharing protocol with private information is followed by a game theoretic proof of the viability of such protocols. / Graduate

Ką, kodėl ir kaip slepia žmogus? Kas yra paslaptis? Kas slepiasi už pačios paslapties? Ar gali būti, kad žmoguje esantys slėpiniai ir pačio žmogaus paslaptys yra Būties paslapties kartotė? Ar galima analizuojant žmogaus paslaptis ką nors sužinoti apie Būtį? Būties stoka įgalina mus laužyti taisykles, dekonstruoti vaidmenis, nusižengti sociumo įstatymams. Būties trokšdami išbandome visus kelius, o bandymų destruktyvią informaciją užkasame kaip vaikiškus sekretus. Žmogus slepia Nerimą. Nerimas slepia Niekį. O “gryna Būtis ir grynas Niekis yra tas pats.”. / What, why and how does a man hide? What is a secret? What hides behind the secret itself? Can it be that the secrets within a human being and the secrets of a man are the repetition of the secret of Being? Is it possible to find out anything about Being by analyzing the secrets of man? The lack of Being empowers us to break the rules, to deconstruct the roles, to violate the laws of the social. While wishing for Being we try out all the ways, and we cover up the destructive information of the attempts as childish secrets. A man hides Anxiety. Anxiety hides Nothingness. “Pure Being and pure Nothing are the same.”.

The world is becoming strongly dependent on computers, and on distributed communication between computers. As a result of this, communication security is important, sometimes critically so, to many day-to-day activities. Finding strategies for discovering attacks against security protocols and for proving security protocols correct is an important area of research. An increasingly popular technique that is used to simplify the design of security protocols is to rely on a secure transport layer to protect messages on the network, and to provide protection against attackers. In order to make the right decision about which secure transport layer protocols to use, and to compare and contrast different secure transport protocols, it is important that we have a good understanding of the properties that they can provide. To do this, we require a means to specify these properties precisely. The aim of this thesis is to improve our understanding of the security guarantees that can be provided by secure transport protocols. We define a framework in which one can capture security properties. We describe a simulation relation over specifications based on the events performed by honest agents. This simulation relation allows us to compare channels; it also allows us to specify the same property in different ways, and to conclude that the specifications are equivalent. We describe a hierarchy of confidentiality, authentication, session and stream properties. We present example protocols that we believe satisfy these specifications, and we describe which properties we believe that the various modes of TLS satisfy. We investigate the effects of chaining our channel properties through a trusted third party, and we prove an invariance theorem for the secure channel properties. We describe how one can build abstract CSP models of the secure transport protocol properties. We use these models to analyse two single sign-on protocols for the internet that rely on SSL and TLS connections to function securely. We present a new methodology for designing security protocols which is based on our secure channel properties. This new approach to protocol design simplifies the design process and results in a simpler protocol.

L'information génétique, de manière intrinsèque, concerne non seulement un individu, mais également les personnes qui lui sont liées par le sang. Dans l'hypothèse où une personne refusait de communiquer des informations cruciales pour la santé des membres de sa famille, les professionnels de la santé qui détiennent ces renseignements pourraient se retrouver confrontés à un dilemme, soit le choix entre le respect de la confidentialité ou la communication des infonnations pertinentes dans l'intérêt de la famille. Ce mémoire propose une analyse des règles régissant la confidentialité des résultats des tests génétiques en regard des droits des membres de la famille et des obligations des professionnels de la santé. Une analyse comparative entre le droit québécois et français est effectuée. La législation portant sur la confidentialité est essentiellement fondée sur la protection des droits individuels. Des exceptions législatives sont toutefois prévues dans l'intérêt de certains membres de la famille, mais elles s'adressent uniquement à la famille biologique. La notion de famille est ainsi restreinte spécifiquement dans le cadre de la génétique. Le bris de la confidentialité ne semble pas la solution optimale pour résoudre le conflit entre les droits de la personne concernée et ceux de sa famille et n'est d'ailleurs pas envisagé par les systèmes juridiques québécois et français. Les professionnels de la santé doivent alors mettre l'accent sur l'information et le dialogue avec le patient, ce qui est davantage garant de la protection des droits de toutes les personnes en cause. / Genetic information, by its very nature, concerns not only the individual, but also the persons related to him by blood. Where an individual refuses to share genetic information crucial to the health of his family members, health professionals who hold such information are faced with a dilemma: they must choose between respecting confidentiality and communicating in the interest of family members. This thesis analyses the rules governing the confidentiality of genetic test results with regards to the rights of family members and the obligations of health professionals. A comparative analysis between the laws of Québec and France is undertaken. Legislation dealing with confidentiality is essentiatly based on the protection of the rights of individuals. Legislative exceptions are nevertheless provided in the interest of certain family members, but they are directed only to the biological family. The concept of "family" is thus restricted in the context of the confidentiality of genetic information. Disregarding confidentiality is not the best solution to the conflict between the rights of the person concerned and of those of his family, and such a solution is not contemplated either in Québec or in France. Health professionals must therefore place emphasis on informing the patient, a solution which offers great protection of the rights of all concemed.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Le premier secret de famille cité par les personnes interrogées par questionnaire est celui de la filiation. Les personnes nées dans le secret (ou nées sous X) sont destinataires d'un secret imposé par la législation, celui de leurs origines biologiques. Si de surcroît, cette adoption leur a été cachée par leur famille, comme c'est le cas des personnes rencontrées dans le cadre de cette recherche, la conséquence en est une souffrance d'autant plus violente que la révélation aura été tardive. Les loyautés familiales contraignent les membres à répéter événements familiaux et les contraignent à payer les fautes de leurs ancêtres. La famille vit enfermée dans un mythe familial qui prescrit les lois et règles à respecter.Aussi, après la révélation, la personne destinataire du secret va refuser ces lois et règles ; elle va être marginalisée par sa famille et le dialogue, voire toutes relations avec sa famille, seront rompus. Ainsi, elle s'est libérée des lois et règles prescrites par le mythe familial et de toute forme de loyauté vis-à-vis de sa famille. Cette exclusion va lui permettre de se socialiser. En effet, dans notre société, la transparence est le fer de lance et "l'extimité" est prônée. Le secret ne s'y oppose pas mais les complémente et la validation du secret est un soutien à la socialisation pour la personne / The first family secret quoted by the people questioned by questionnaire is that of filiation. The people born in the secret (or born under X*) are recipients of a secret imposed by legislation, that of their biological origins. If in addition, this adoption was hidden from them by their family, as is the case of the people met in the context of this research, the consequence is a all the more violent in terms of suffering as the revelation will have been late. Family loyalty forces members to repeat family events and forces them to pay for the faults of their ancestors. The family lives lockecl up in family myth which prescribes the laws and rules to be respected. And so, after the revelation, the person recipient of the secret will refuse these laws and rules ; he or she will be marginalized by his or her family and dialogue, or even all relations with his or her family, will be broken. Thus, he or she was released from the laws and rules prescribed by family myth and from any form of loyalty with respect to his or her family. This exclusion will enable him or her to become sociable. Indeed, in our society, this transparency is triumphed and "extimity" is applauded. Secrets are not opposed to this but are complimentary and the valid ation of the secret is a support for the socialization of the person