  This paper examines the problem of distributing rewards on social networks to
improve the efficiency of crowdsourcing tasks for sponsors. To complete the
tasks efficiently, we aim to design reward mechanisms that incentivize
early-joining agents to invite more participants to the tasks. Nonetheless,
participants could potentially engage in strategic behaviors, e.g., not
inviting others to the tasks, misreporting their capacity for the tasks, or
creaking fake identities (aka Sybil attacks), to maximize their own rewards.
The focus of this study is to address the challenge outlined above by designing
effective reward mechanisms. To this end, we propose a novel reward mechanism,
called Propagation Reward Distribution Mechanism (PRDM), for the general
information propagation model with limited budgets. It is proved that the PRDM
can not only incentivize all agents to contribute their full efforts to the
tasks and share the task information to all their neighbors in the social
networks, but can also prevent them from Sybil attacks.
