Customers are getting opportunity to login to a cloud to use as much resources as they need paying for only those resources they use. Such a nice service oriented computing is becoming controversial due to the lack of privacy and security issues. On a recent survey conducted by IDC 87.5% participants shows security as a reason for reluctance on the part of enterprise IT to aggressively adopt Cloud Computing. To have a secured Cloud Computing few areas - identity and access management, segregation of data, data destruction after service contract ends, reliability, confidentiality, regulatory compliance, integrity of data, privacy, geographic boundary of data, virtual network intrusion detection/prevention (IDS / IPS) have to be resolved. Managing access control and governing within Identity and Access Management (IAM) to meet today s business need in the cloud remains one of the major hurdles for enterprise adoption of cloud services. In this book a prototype of Identity and Access Management (IAM) using Diffie- Hellman, Kerberos, RBAC and XML has been developed for helping enterprise IT organizations and cloud provider to improve their service.