Sensor networks are expected to be deployed ubiquitously in our environment serving different purposes ranging from smart dust to ubiquitous/pervasive services. The latter may be viewed in a service centric way, in contrast to the more typical data centric view related to smart dust. These services should be dynamically deployable and composable in a secure way. Security is extremely important since sensor nodes can be easily deployed in the environment and interact with other sensors. It needs to be avoided that these sensors are compromised and hinder the correct operation of the sensor network. The poster presents an innovative approach towards secure service discover and lookup in sensor networks.