Le contrôle d'agrégation dit Quantity Based Aggregation (QBA) est lié au contrôle de l'inférence dans les bases de données et a rarement été traité par la communauté scientifique. Considérons un ensemble S formé de N éléments. L'agrégation d'éléments de l'ensemble S n'est considérée comme étant confidentielle qu'à partir d'un certain seuil k, avec k < N. Le but du contrôle QBA est donc de garantir que le nombre d'éléments de S délivrés à un utilisateur reste toujours inférieur à k. Dans cette thèse, nous traitons du problème du contrôle QBA dans les bases de données cadastrales. Ce travail répond à un besoin du service des affaires foncières de la Polynésie française. La politique de sécurité qu'il nous a été demandé d'implanter donne le droit à chaque utilisateur de connaître le propriétaire de n'importe quelle parcelle. Cette permission est toutefois limitée par les interdictions suivantes: l'utilisateur ne doit jamais arriver à connaître 1- tous les propriétaires dans une région donnée, et 2- toutes les parcelles appartenant au même propriétaire. Chacune de ces interdictions correspond, de manière évidente, à un problème de type QBA. Dans cette thèse, nous développons d'abord un modèle pour assurer la première interdiction, ensuite nous montrons comment adapter notre modèle à la seconde interdiction. Nous présentons, en outre, une implémentation de notre modèle pour les bases de données relationnelles. / Quantity Based Aggregation (QBA) controls closely related to inference control database and has been rarely addressed by the scientific community. Let us consider a set S of N elements. The aggregation of k elements, at most, out of N is not considered sensitive, while the aggregation of mor than k out of N elements is considered sensitive and should be prevented. The role of QBA control is to make sure the number of disclosed elements of S is less than or equal to k, where k<N. In this thesis we work on QBA problems in the context of cadastral databases. This work addresses an actual need of the real-estate service of French Polynesia. The security policy, that we were asked to implement, gives every user the right to know the owner of any parcel in the database. This permission is, however, constrained with the following prohibitions: the user cannot acquire the knowledge of the owners of all parcels in a given region, and all parcels belonging to the same owner. Each prohibition represents, obviously, a distinct QBA problem. In this manuscript, we develop a model to enforce the first prohibition, then we show how this work can be adapted to the enforcement of the second prohibition. Afterwards, we present an implementation for relational databases. Our model addresses several aspects: We take collusions into account (when multiple users collaborate to circumvent the security policy). We discuss the notion of a region and we propose two basic definitions: the “zone” and the “dominant zone.” • We discuss database updates specific to the cadastral application, and its implications on QBA control. We propose a scheme to handle buy, sell, merge and split operations. We propose a strategy to handle access history in order to guarantee that honest users do not get blocked indefinitely on a set of accessible parcels, thus increasing the availability and the utility of the database. At the end of this manuscript we present the prototype we developed to showcase QBA control, in addition to benchmarks showing the advantage of one definition of a region (the “dominant zone”) over another (the “zone”). We show that the adoption of the “dominant zone” increases data availability and improves the performance of the QBA control enforcement algorithm.

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The paper focuses on the issue of access control. It presents an universal bilateral protocol of access control of ACP. The paper describes the messages and its sequences that AC portals uses for communication. It describes the functions and features of the modules from which the portal is composed. The paper suggests the concept of a modular AC portal solutions including the design of basic modules. It also outlines possible test scenarios. Under this proposal is generated functional AC portal on the .NET Framework platform using the C\# programming language. The portal provides access to local assets or to the assets on other computers in the local network. Created application is tested according to the scenarios proposed in both the network version and the local version of the AC portal. Test results are objectively evaluated and commented.