Situational awareness is a key concept in cyber-defence. Its goal is to make the user aware of different and complex aspects of the network he or she is monitoring. This paper proposes PERCIVAL, a novel visual analytics environment that contributes to situational awareness by allowing the user to understand the network security status and to monitor security events that are happening on the system. The proposed visualization allows for comparing the proactive security analysis with the actual attack progress, providing insights on the effectiveness of the mitigation actions the system has triggered against the attack and giving an overview of the possible attack's evolution. Moreover, the same visualization can be fruitfully used in the proactive analysis since it allows for getting details on computed attack paths and evaluating the mitigation actions that have been proactively computed by the system. A preliminary user study provided a positive feedback on the prototype implementation of the system. A video of the system is available at: https://youtu.be/uMpYCJCX95k

While multi-player online games are very successful, their fast deployment suffers from their server-based architecture. Indeed, servers both limit the scalability of the games and increase deployment costs. However, they make it easier to control the game (e.g. by preventing cheating and providing support for billing). Peer-to-peer, i.e. transfer of the game functions on each each player's machine, is an attractive communication model for online gaming. We investigate here the challenges of peer-to-peer gaming, hoping that this discussion will generate a broader interest in the research community.

Until recently, ad hoc networks were mainly used for military and security-sensitive applications. Nowadays, they could also be used in SOHO (Small Office / Home Office) or home networks. In such networks, devices are linked by long term relations. To ensure their security, it is necessary to define precisely which devices belong to a given network and are consequently inside the security perimeter. The chosen mechanisms need to be easy to use, because the users of SOHO and home networks are neither willing nor able to configure the security of their network. In this paper, we present a new fully distributed approach for securing long term communities of devices in SOHO and home ad hoc networks that minimizes user intervention.

Reputation systems allow to estimate the trustworthiness of entities based on their past behavior. Electronic commerce, peer-to-peer routing and collaborative environments, just to cite a few, highly benefit from using reputation systems. To guarantee an accurate estimation, reputation systems typically rely on a central authority, on the identification and authentication of all the participants, or both. In this paper, we go a step further by presenting a distributed reputation mechanism which is robust against malicious behaviors and that preserves the privacy of its clients. Guaranteed error bounds on the estimation are provided.