In multi-hop wireless networks, the mobile nodes usually act as routers to relay other nodes' packets for enabling new applications and enhancing the network performance and deployment. However, selfish nodes may not cooperate and make use of the cooperative nodes to relay their packets, which has negative effect on the network fairness, security, and performance. Incentive systems implement micropayment in the network to stimulate the selfish nodes to cooperate. However, micropayment schemes have been ...