Abstract: Secure communication, an important aspect of any networking environment is an especially significant challenge in mobile ad hoc networks. Masquerading and eavesdropping are major threats to the security of wireless communications and mobile networks. The scheme proposed in this study describes the framework to solve the security threats by designing a certificateless based cryptography scheme. Certificateless Routing Method (CRM) as a combination of ad hoc node address and public key cryptography. CRM is a certificateless public key cryptography solution in that public keys of mobile nodes are directly derivable from their known Ad hoc node address plus some common information. Thus, it eliminates the need for certificate-based authenticated public-key distribution essential in conventional public-key management schemes. CRM is an efficient construction method of address-based public/private keys cryptography which not only ensures high-level authentication to node exchange information but also enables efficient network-wide secure key update via a single broadcast message. It also provides general information about how to choose the secret key sharing parameters used with public key cryptography to meet desirable levels of security and authentication. The advantages of CRM over existing certificate-based solutions are justified through extensive simulations. The proposed scheme CRM gives a new innovation towards more effective and efficient security design for MANETs.