Recent progresses in wireless sensor networking and pervasive computing have created huge opportunities for providing elderly people with technological facilities. For elderly people, conceiving technologies for increasing their autonomy, so as to enable them to self-manage their life is of utmost importance. However, when it comes to smart home, once all appliances in a home are automated and connected through internet, it becomes essential to consider issues of security, especially security configuration. In the smart home, security has to be configured and managed by technology-unaware elderly people. One mechanism of auto security configuration in such environment can be achieved by observing the trustworthiness of smart devices. Trust-based security mechanisms allow access rights to evolve among previously unknown devices, thus minimizing security configuration. In this paper, we present a security configuration model which takes critical security decisions by determining the trustworthiness of an entity based on the sources of trust: Direct interaction and Recommendation trust.