Security of mobile ad hoc network is crucial due to infra structure less network and mobility of wireless media. In this paper, the authors propose an Hybrid Routing Protocol for Unobservable Secured (HRPUS) to offer privacy preservation to all types of packets. HRPUS works with USOR (Unobservable Secure On-demand Routing protocol) to protect against block hole attack. In ad hoc network, when a source searches for a route to a destination using HRPUS protocol, an intermediate node can reply with its cached entry. To strengthen correctness of such routing discovery process, they propose a method in which the intermediate node requests its next hop to send a confirmation message to the source.