Growing levels of digitalization and broadband access drives extremely fast progress in multimedia and networking technologies and allows consumers to create requirements at an accelerating rate. Producers response is to emphasize the speed of delivery and upgradability of applications. Development of Web services and service-oriented architecture puts the emphasis on creation of specific services which then can be aggregated to achieve a particular goal. By substituting or adding new services, a particular application can be adapted faster to changing requirements. Any application thus composed must address security concerns, including security guarantees after a service substitution. Based on our framework for creating multimedia collaborative authoring applications from a set of standard services, we provide a security analysis of the resulting application and present a novel framework for ensuring uniform access control guarantees across different constituent services

As computer infrastructures become more complex, security models must provide means to handle more flexible and dynamic requirements. In the organization based access control (Or-BAC) model, it is possible to express such requirements using the notion of context. In Or-BAC, each privilege (permission or obligation or prohibition) only applies in a given context. A context is viewed as an extra condition that must be satisfied to activate a given privilege. We present a taxonomy of different types of context and investigate the data the information system must manage in order to deal with these different contexts. We then explain how to model them in the Or-BAC model.

This paper presents the work we have done within the MIRADOR project to design CRIM, a cooperative module for intrusion detection systems (IDS). This module implements functions to manage, cluster, merge and correlate alerts. The clustering and merging functions recognize alerts that correspond to the same occurrence of an attack and create a new alert that merge data contained in these various alerts. Experiments show that these functions significantly reduce the number of alerts. However, we also observe that alerts we obtain are still too elementary to be managed by a security administrator. The purpose of the correlation function is thus to generate global and synthetic alerts. This paper focuses on the approach we suggest to design this function.