FBI official declared before a House panel that the phenomenon of cyber espionage is increasing with an alarming trend. Cyber espionage is largely diffused both in private and governments sectors, the opportunity to acquire sensible information in this way could give a great advantage to the attackers. The practice of the cyber espionage could be perpetrated in a long interval of time causing dramatic problems, emblematic the case of Nortel firm that has terminated in bankruptcy. China is worlds biggest cyber attack victim according a recent report published by the National Computer Network Emergency Response Coordination Center of China.”]