The main objective of TRESOR is the development of a cloud ecosystem that consists of an open platform for cloud services and a cloud broker. The first component provides a marketplace for cloud services based on well-established standards maximizing interoperability between different cloud providers. In that way, cloud services can be easily combined and integrated into several applications leading to cost savings and decreasing dependencies, so-called lock-in effects, to certain cloud providers. The cloud broker, on the other hand, mediates, combines and allows the access to those cloud services by taking enterprise guidelines, regulations by law and security policies into consideration. Furthermore, the broker applies new concepts of location-aware service usage and data storage.