Abstract: In ad-hoc networks, mobile devices communicate via wireless links without the aid of any fixed networking infrastructure. These devices must be able to discover services dynamically and share them safely, taking into account ad-hoc networks requirements such as limited processing and communication power, decentralised management, and dynamic network topology, among others. Legacy solutions fail in addressing these requirements. In this paper, we propose a service discovery protocol with security features, the Secure Pervasive Discovery Protocol. SPDP is a fully distributed protocol in which services offered by devices can be discovered by others, without a central server. It is based on an anarchy trust model, which provides location of trusted services, as well as protection of confidential information, secure communications, or access control. Key Words: ad-hoc networks, service discovery protocol, security, trust Category: C.2.2, C.4