Abstract—We propose a secure distributed transport protocol for wireless sensor networks that resists against attacks on the reliability service provided by the protocol, as well as against energy depleting attacks. Our protocol is based on the Distributed Transport for Sensor Networks (DTSN) protocol, to which we add a security extension that consists in an efficient, symmetric key based authentication scheme for control packets. Besides describing the operation of our protocol, we also provide its analysis in terms of security and overhead. I.