The Smart Grids combine and integrate the now ubiquitous computational capabilities with the traditional power grid. This integration will lead to a considerable increase of efficiency and reliability of energy distribution among the consumers (domestic or industrial environment). This objective is achieved by distributing thousands (and/or millions) of interconnected sensors and smart electronic devices on the network. This feature is the strength and the weakness of the Smart Grids, in fact every single device connected to the Smart Grids will be a potential entry point to further attacks on the entire network.