Cloud computing is an emerging topic amongst IT personnel. Pay-as-you-go is the basis of cloud computing. It makes data services to be available in enormous speed and with greater ease but the data reside outside the organization's boundaries. Trusting the cloud provider is inevitable. Building Trust is the need of the hour and one organization cannot live without it. The authors will study the key factors thereby which they will be able to measure and build trust between the cloud provider and the user.