The Helix Nebula initiative is a partnership between leading European IT-intense scientific research organisations (CERN, EMBL and ESA) and leading IT cloud providers. Its goal is to form a federated Cloud Computing infrastructure that will satisfy the growing demand of scientists for computing power. The concept of the federated cloud requires a standard framework named BlueBox so that current and future cloud providers are able to smoothly interface their system to the existing multi-cloud infrastructure.