There are four main types of cloud computing: private clouds, public clouds, hybrid clouds, and multi-clouds. These types of cloud computing run in a cloud computing service, which main types are: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), Software-as-a-Service (SaaS) and Function-as-a-Service (FaaS). The four main types of cloud computing differentiate in terms such as of location, ownership, multitenancy, etc. Public clouds often have a wider attack surface, but can also deploy comprehensive infrastructural protection usually not available in other cloud (such as Distributed-Denial-of-Sevice or DDoS protection). In contrast, private clouds can be more fine-grained secured due to specific security measures being applied by the organization. Hybrid and multi-cloud usually offer a mix of both worlds.