Wireless sensors, which are smaller and cheaper, have started being used in many different applications. Military applications, health care and industrial monitoring, environmental applications, smart grids, and vehicular ad-hoc networks are some of the best known applications of wireless sensors. In some applications, especially military, environmental, and health care applications, it is required that the communication between sensor nodes be encrypted to achieve privacy and confidentiality. In this work, some modifications have been made to the ad-hoc on-demand distance vector routing protocol, mostly preferred in wireless sensor networks, to make data communications more reliable. The proposed routing protocol is shown to be capable of detecting and eliminating malicious blackhole nodes. It also secures the transmitted data. The proposed mechanism has been compared with the original ad-hoc on-demand distance vector routing protocol in terms of average end-to-end delay and data delivery ratio. The performance evaluations show that the proposed secure routing protocol eliminates malicious nodes in the network. Furthermore, it achieves almost the same delivery ratios as the original ad-hoc on-demand distance vector routing protocol and does not cause extra communication delay.