\input zb-basic \input zb-ioport \iteman{io-port 05601229} \itemau{Klaoudatou, Eleni; Konstantinou, Elisavet; Kambourakis, Georgios; Gritzalis, Stefanos} \itemti{A cluster-based framework for the security of medical sensor environments.} \itemso{Fischer-H\"ubner, Simone (ed.) et al., Trust, privacy and security in digital business. 6th international conference, TrustBus 2009, Linz, Austria, September 3--4, 2009. Proceedings. Berlin: Springer (ISBN 978-3-642-03747-4/pbk). Lecture Notes in Computer Science 5695, 52-62 (2009).} \itemab Summary: The adoption of Wireless Sensor Networks (WSNs) in the healthcare sector poses many security issues, mainly because medical information is considered particularly sensitive. The security mechanisms employed are expected to be more efficient in terms of energy consumption and scalability in order to cope with the constrained capabilities of WSNs and patients' mobility. Towards this goal, cluster-based medical WSNs can substantially improve efficiency and scalability. In this context, we have proposed a general framework for cluster-based medical environments on top of which security mechanisms can rely. This framework fully covers the varying needs of both in-hospital environments and environments formed ad hoc for medical emergencies. In this paper, we further elaborate on the security of our proposed solution. We specifically focus on key establishment mechanisms and investigate the group key agreement protocols that can best fit in our framework. \itemrv{~} \itemcc{} \itemut{Wireless Sensor Networks; Security; Medical Environments; Clustering; Group key management} \itemli{doi:10.1007/978-3-642-03748-1\_6} \end