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.