Many active attacks like Blackhole, wormhole, Sybil attacks, Replay attacks and many different types of passive attacks at different layers may destroy network functioning completely. For secure communication within MANETs there must have some provision for security of small size entities. So it is extremely desirable to design separate secure routing protocols for MANETs which can prevent communication data from being corrupt and can withstand other network related constraints efficiently. In this research work we have focused on analyzing the effect of active attacks on the performance of basic routing protocols, like Ad-Hoc On Demand Distance Vector Routing (AODV), Dynamic Source Routing (DSR) and Dynamic MANET On-Demand Distance Vector Routing (DYMO).We have designed secure routing protocol for MANET based on Certificateless Pairing-free Cryptosystem which removes inherent Key Escrow problem of certificate based cryptosystems and reduces large computational cost of pairing operations. Another design of secure routing protocol is based on Lattice Based Public Key Cryptosystems which is unbreakable even with future Quantum Computers.