Recent advances in portable computing and wireless technologies are opening up exciting potential for the future of wireless mobile networking. A Mobile Ad hoc NETwork (MANET) consists of movable platforms which are free to move arbitrarily. The flexibility of mobile ad hoc network introduces new security threats. Many conventional security solutions used for wired networks are ineffective and inefficient for the highly dynamic and resource-constrained environments where use of MANET may be predictable. In this paper, the authors generally focus on the authentication frameworks for the mobile ad hoc networks.