Abstract: This paper describes an automatically determination process of the security services for products and services on the Internet of Things. This process has as inputs the service context, the legislative diversity and the information involved among others. Considering the resources limitations in a Wireless Sensor Networks and the already mentioned inputs, it is possible to find the best solution to apply in each specific case. We will introduce the "Utility Matrix" as a main concept to link all interests of stakeholders regarding their security needs and the legal imperatives. The final solution has been implemented with an expert system. The process outputs are composed by several products as a security policy for the service; a protected data certification, and an effective tool to simulate and evaluate impacts over new services or when service conditions or laws change. Challenges to research over new technical solutions needs can also be obtained. This proposal will connect the Industrial, Judicial and Technological areas working together to obtain trustworthy certifications for all stakeholders.The results have been evaluated in a real scenario made up of a Wireless Sensor Network, over middleware service oriented platform in the framework of “AWARE project” and the expert system connected to the platform in order to configure the security services.