Mobile ad hoc networks (MANETs) are dynamically self-organized, temporary networks between mobile wireless devices. These networks are particularly vulnerable to security threats due to the absence of centralized control and the inherent insecurity of wireless communication channels. This study proposes the Secure Zone Routing Protocol (SZRP) to facilitate secure packet transmission between connected mobile nodes across various levels. SZRP is developed by integrating advanced cryptographic techniques, including the AES encryption system and the SHA hashing algorithm, into the Zone Routing Protocol (ZRP) framework. We conducted extensive simulations using Network Simulator 2 (NS-2) to evaluate SZRP’s performance in terms of packet delivery fraction, routing load, route acquisition latency, and resilience against malicious attacks. The results demonstrate that SZRP enhances the security of MANETs while maintaining efficiency comparable to traditional routing protocols. This work contributes to developing more secure and robust mobile networks, offering the potential for applications in diverse fields requiring reliable communication.