Mobile applications dealing with ad-hoc situations do have their own challenges such as a reasonable short time for interaction and limitations of available technology. A secure yet user-friendly solution for protecting wireless communication therefore is a service enabler for mobile business. This paper discusses the drawbacks of existing security concepts and proposes a framework on application level to help developers improving user acceptance. Additionally, we present the evaluation results of the prototype which leverages the user's common spatial context by integrating him into the device authentication process.