Vehicular ad hoc networks (VANETs) are envisioned to provide us with numerous interesting services in the near future. One of the most promising applications is the dissemination of commercial advertisements via car-to-car communication. However, due to non-cooperative behavior of selfish nodes or even malicious ones in the real-world scenario, such vehicular advertisement system cannot be realized unless proper incentives and security mechanisms are taken into consideration. This paper presents Signature-Seeking Drive (SSD), a secure incentive framework for commercial ad dissemination in VANETs. Unlike currently proposed incentive systems, SSD does not rely on tamper-proof hardware or game theoretic approaches, but leverages a PKI (Public Key Infrastructure) to provide secure incentives for cooperative nodes. With a set of ad dissemination designs proposed, we demonstrate that our SSD is robust in both incentive and security perspectives. Categories and Subject Descriptors C.2.0 [Com...