This document discusses data security in cloud computing. It defines cloud computing and describes the types including SaaS, PaaS, and IaaS. It also covers deployment types such as private, public, and hybrid clouds. While cloud computing provides security advantages through data centralization and logging, it also poses security disadvantages regarding data location and regulatory compliance. Major security threats in the cloud include abuse of cloud services, insecure APIs, and data loss. Risk analysis approaches are needed to estimate security risks and ensure customer data protection in the cloud.