Future electrical power grids (smart grids) use information and communication technology to improve power system control beyond what has been possible in the past. The objectives are, among others, to enable efficient use of renewable energy resources, to ensure security of electricity supply and to support future energy market structures. This requires data exchange between various legacy and future applications in the smart grid. To facilitate this, a flexible communication platform is required. A central question of this work is what such a communication platform should look like. Concepts for resilient communication, integration of legacy and future smart grid applications, and secure communication over untrusted infrastructures are des...