""In recent years, with the growing popularity of Cloud Com-. puting, security in Cloud has become an important issue. Cloud Com-. puting paradigm represents an opportunity for users to reduce costs and. increase efficiency providing an alternative way of using services. It rep-. resents both a technology for using computing infrastructures in a more. efficient way and a business model for selling computing resources. The. possibility of dynamically acquire and use resources and services on the. base of a pay-per-use model, implies incredible flexibility in terms of. management, which is otherwise often hard to address. On the other. hand, because of this flexibility, Denial of Service attacks represent a. serious danger, which can compromi...