In Mobile Ad-hoc network every node can change its position dynamically without having any fixed infrastructure. The path information is maintained permanently for routing the data packets. Due to the open nature of wireless networks, it is vulnerable to attack by the malicious nodes. The entire network performance is reduced by packet forwarding attack; packet is dropped by malicious nodes. To increase energy efficiency of mobile nodes, an improved security method against packet forwarding misbehavior attack is introduced. This paper proposed Cryptographic based Malicious Node Detection and Secure Routing (CBMNDSR) framework. This framework consists of three algorithms namely access control algorithm to prevent the unauthorized nodes initially, malicious node detection and avoiding algorithm based on hop count and secure routing algorithm using randomly generated private key such as One Time Password(OTP). The detection procedures are energy aware because in a challenging environment only a minimum set of nodes in the network having a sufficient energy to perform networking functions. The detection method is executed quickly for identifying and isolating the malicious nodes. Secure routing based Cryptographic Key exchange algorithm is implemented in order to improving the security of MANET. The simulation results show that the proposed method identifying malicious nodes efficiently in MANET. The malicious node detection rate is increased 95% and energy consumption is 10% better than then existing methods.