International Journal of Scientific Research and Engineering Development

Cloud computing isa way of using computer resources over the internet. It lets users access shared Pools of computing resources, like servers, networks, and storage, on demand. This has become a big change in the world of Information Technology (IT). Even though cloud computing offers many benefits ,like saving money, being able to grow quickly, and being flexible, there are still major issues with data security and privacy that stop it from being widely used, especially by big companies and in sensitive situations. This paperbrings together information from various studies to talk aboutthe different ways cloud computing is set up, how it's deployed, the main security threats, and ways to deal with those threats.It explains the three main service models Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a service (IaaS) as well as the different ways it can be deployed, like public, private, hybrid, and Com-munity clouds. It also looks closely at security and privacy issues throughout the entire life of data,including making sure data stays safe, private,and accessible.The paper discusses advancedways to protect data, like Homomorphic Encryption, Attribute-Based Encryption (ABE), and Searchable Encryption. It also looks at best practices that organizations can use,such as strong access controls and regular security checks. It highlights howthese challenges are changin granging from problemswith multiple users sharing the same resources and people with too much access to more complex threats like sichannel attacks and attacks that could become a problem with quantum computers. The paper stresses the need fora complete, in tegrated, and standardized approach to security and trust in cloud environments to enure they are safe to use.