Cloud computing refers to the underlying infrastructure for an emerging model of service provision that has the advantage of reducing cost by sharing computing and storage resources, combined with an on-demand provisioning mechanism relying on a pay-per-use business model. These new features have a direct impact on Information Technology (IT) budgeting but also affect traditional security, trust and privacy mechanisms. The advantages of cloud computing – its ability to scale rapidly, store data remotely, and share services in a dynamic environment – can become disadvantages in maintaining a level of assurance sufficient to sustain confidence in potential customers.