Architecture and security in networked virtual environments

Abstract

During the last years, large-scale simulations of realistic physical environments have become increasingly available and economically viable, most notably in the computer gaming industry. Such systems, commonly called networked virtual environments (NVEs), are usually based on a client-server architecture where for performance reasons and bandwidth restrictions, the simulation is partially delegated to the clients. The first two parts of this thesis are concerned with software engineering challenges in NVE technology. In the first part, we analyze the domain of large-scale NVEs in order to determine the scope of suitable middleware solutions for NVEs with special emphasis on Massive Multiplayer Online Games (MMOGs). In the second part, we develop a design approach for such a next-generation middleware. We elaborate a set of domain-specific services and develop a middleware approach for the simulation services which uses transactions with weak isolation levels as key-concept. In the third part of this thesis, we address the security of NVEs. We argue that in addition to classical security threats, NVEs are inherently vulnerable to attacks against the semantic integrity of the simulation. We initiate the systematic study of semantic integrity in NVEs from a security point of view. Furthermore, we present a new resource efficient and provably secure semantic integrity protocol which enables the server system to audit the local computations of the clients on demand.