Cloud computing enables the storage of data independent from own hardware. Basis is the internet. Cloud-based solutions can offer three different type of services. The charging model is usually pay-per-use. Software as a Service (Saas) is the uppermost service layer and contains the provision of software to use. Platform as a Service (PaaS) is the middle service layer and offers the foundation for developers to offer databases and software. Infrastructure as a Service (IaaS) is the third layer providing the customer with computer power, storage and network infrastructure. The use of cloud computing decreases the costs for maintenance and administration of local storages. Mobile offices are a use case for cloud computing as data are available everywhere requiring a valid internet connection. This service is different between private clouds, accessible only internally and public clouds offered in the internet. A combination of both is called hybrid cloud.