In the modern communication world, a network can be built on the fly using mobile nodes with networking capability. Such a network without any pre-existing support for communication is referred to as a Mobile Ad Hoc Network (MANET). It can be deployed in essential areas such as military and civilian environments and disaster management circumstances because of its ad hoc nature. However, with their flexibility and utility, MANETs are inherently vulnerable to a range of attacks due to their decentralized nature and lack of central oversight. Among these threats, black-hole attacks, where malicious nodes absorb and discard data packets, pose a significant risk to network reliability and security. Existing solutions for blackhole attack prevention and detection in MANETs often rely on techniques that require the cooperation of malicious nodes, such as monitoring the sequence number difference in RREP messages. However, the behavior of blackhole nodes is generally more unpredictable. Additionally, the reliance solely on sequence number differences makes the detection mechanism ineffective in identifying blackhole nodes that send legitimate-looking RREP messages. These limitations reduce the effectiveness of the proposed solutions in MANETs, where black hole nodes can use more sophisticated tactics to evade detection. This thesis addresses this critical issue by proposing an enhancement to the AODV routing protocol, utilizing the security features of the ECDSA to counter black-hole attacks. ECDSA is chosen for its robust security features and efficiency, providing strong authentication and data integrity with relatively smaller key sizes compared to other cryptographic algorithms. The integration of ECDSA into the AODV protocol ensures that only legitimate nodes, verified through digital signatures, can participate in the network. Comprehensive simulations conducted using NS-3.30 that the ECDSA-enhanced AODV protocol outperforms existing security-AODV protocols. Key performance metrics, including average throughput, PDR, E2ED, and normalized routing overhead. These enhancements validate the proposed solution's efficacy in ensuring secure and efficient routing operations within MANETs. The thesis thus presents a holistic approach to addressing critical security challenges, emphasizing authentication, authorization, confidentiality, integrity, and non-repudiation, ultimately proving the superiority of the ECDSA-enhanced AODV protocol. Keywords: Mobile Ad Hoc Network, Ad hoc On-Demand Distance Vector, Elliptic Curve Digital Signature Algorithm