A hybrid cloud model combines private cloud or private infrastructure with public cloud resources. It allows an organization to keep sensitive workloads or data in a controlled private environment while using public cloud capacity for elasticity, scalability, geographic reach, or cost optimization. This model is common when organizations have regulatory requirements, legacy systems, or sensitive datasets that cannot be moved fully into a public cloud, but still need the flexibility of public services. A public cloud is shared provider-operated infrastructure available to many customers. A private cloud is dedicated to one organization but does not inherently provide public cloud scalability unless integrated with it. A community cloud is shared by organizations with common requirements, such as sector-specific compliance needs. Hybrid cloud security requires consistent visibility, identity controls, policy enforcement, and shared responsibility awareness across both private and public components. Reference/topics: Cloud Security 5.1, cloud-computing deployment models; Cloud Security 5.3, shared responsibility model.