We present a scheme for secure and privacy-preserving communication in hybrid ad hoc networks. Our scheme enables users to secure communication and to protect their anonymity and location privacy. Our approach is based on frequently changing node pseudonyms and cryptographic keys, which enable users to avoid being identified by the locations they visit, or by the type of traffic they generate. We show how our scheme can be effectively used for secure and private routing in hybrid ad hoc networks. We study the robustness of the proposed solution with respect to various attacks. We further show that the proposed solution introduces a very moderate overhead to the network operation.