This document discusses methods for ensuring data security in cloud computing environments. It begins by introducing cloud computing models including infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). The main goals of data security - confidentiality, integrity, and availability - are then described. Several methods for data security are proposed, including data fragmentation where sensitive data is divided and distributed across different domains. Encryption techniques are also discussed as ways to protect confidential data during storage and transmission. Overall, the document aims to evaluate approaches for addressing key issues around securing user data in cloud systems.