Today, the latest example of cloud computing is Web 2.0;Google, Yahoo, Microsoft, and other service providers now offer browserbased enterprise service applications (such as webmail andremote data backup). Now thatcloud computing has emerged asa viable and readily available platform, many users from disparate backgrounds (for example, financial institutions, educators, or cybercriminals) are sharing virtual machines to perform their dailyactivities. This environment re-quires an implicit level of trust aswell as an explicit level of vigilance to ensure success