trustd: Trust daemon experimental testbed for network emulation

Various trust models have recently been proposed in order to develop trust-based security and/or network services. Although the trust models have been tested through extensive simulation to verify and validate their performance gains, there has been little effort to validate the models using network emulation to provide more realistic network characteristics. In this work, we present trustd, a trust daemon created to provide a capability to evaluate trust in distributed network environments. trustd has been deployed in CORE (Common Open Research Emulator), which enables the system to conduct peer-to-peer trust estimation in a fully distributed emulated network. In this work, we present the architectural framework and implementation details of trustd. In particular, we discuss the process of taking the trust metric theory and implementing it as a UNIX-system daemon providing trust-evaluation services to the system. In addition, we compare our experimental and simulation results and analyze their trends in terms of the accuracy of trust estimation and trust evolution over time in the presence of malicious nodes in the network.