Secret Key Establishment for Symmetric Encryption over Adhoc Networks

The adhoc environment is accessible to both legitimate network users and unfortunately to malicious attackers as well. Secure routing over mobile adhoc networks is hard to achieve because of dynamic topology, mobility of nodes, lack of centralized infrastructure and absence of a certification authority. When a new mobile node joins the network and it does not have any trust based relationship with other nodes in the network, the problem of secure routing may arise. While implementing data encryption and decryption in a symmetric cryptosystem, secure distribution of the secret key to legitimate nodes can be a challenge. In this paper, common secret key has been established for symmetric encryption over adhoc networks using Diffie-Hellman key agreement protocol. The concept can be used to develop a new routing protocol for mobile adhoc networks which will provide maximum security against all kinds of attacks.