With today's ongoing integration of heterogeneous building automation systems, increased comfort, energy efficiency, improved building management, sustainability as well as advanced applications such as active & assisted living scenarios become possible. These smart homes and buildings are implemented as decentralized systems, where embedded devices are connected via networks to exchange their data. Obviously, the demands - especially regarding security - increase: Secure communication becomes equally important as secure software being executed on the embedded devices. While the former has been addressed by standardization committees, manufacturers and researchers, until now the problem of secure control applications in this domain has not been addressed extensively. This leads to insecure and unprotected software being executed on the embedded devices. Thus, adversaries are capable of attacking building automation systems. This paper introduces an architecture for distributed control applications in smart homes and buildings, which tackles the problem on how to secure software running on different device classes. The following novelties are contributed: an application model capable of depicting control applications in a formal way, the concept of security attributes, being able to formally specify a security policy, and a framework, which allows the secure development and execution of control applications, and an enforcement of the defined security policies.