Multilevel Security Model using Distributed Keys in MANET

In military areas where MANET is used, enemy can physically capture soldier mobile device and can use stored private key to sign unauthorized messages. To overcome this security issue Shamir‟s (t, n) threshold secret sharing scheme is used to protect stored private key. Using this scheme the user private key is decomposed into „n‟ parts and distributed to „n‟ nodes in network. So when user wants his private key to sign message he just requests „t‟ or more key shares from any „t‟ out of „n‟ nodes to reconstruct private key. But t-1 shares can‟t reconstruct the private key. Also, for securing the bandwidth and resources in MANET Shamir identity based cryptosystem and signature scheme is used, where a unique user identity is used as public key for encryption and decryption of messages. So, there is no requirement of certification and distribution of public key. We are proposing this security model for a Two tier ad hoc network architecture.