This project aims to tackle the challenge of improving the security and dependability of cloud computing services using recent techniques investigated under designations such as resilience, Byzantine fault tolerance or survivability, which we call intrusion tolerance or InTol for short. InTol has deserved much research in recent years since it can be used to obtain both fault tolerance and added security. InTol departures from the fact that complex systems cannot be made entirely secure. However, similarly to accidental faults, attacks and intrusions in components of a system can be tolerated, leaving the system as a whole working properly, i.e., satisfying availability, integrity and confidentiality properties, despite such events. A common approach is to use the state machine approach to scatter a service by several servers in such a way that even if some of the servers are compromised, the service as a whole remains correct.