  Mobiles are nowadays the most relevant communication devices in terms of
quantity and flexibility. Like in most MANETs ad-hoc communication between two
mobile phones requires mutual trust between the devices. A new way of
establishing this trust conducts social trust from technically measurable data
(e.g., interaction logs). To explore the relation between social and technical
trust, we conduct a large-scale survey with more than 217 Android users and
analyze their anonymized call and message logs. We show that a reliable a
priori trust value for a mobile system can be derived from common social
communication metrics.
