  Security in any of the networks became an important issue in this paper we
have implemented a security mechanism on Medium Access Control layer by Assured
Neighbor based Security Protocol to provide authentication and confidentiality
of packets along with High speed transmission for Ad hoc networks. Here we have
divided the protocol into two different parts. The first part deals with
Routing layer information; in this part we have tried to implement a possible
strategy for detecting and isolating the malicious nodes. A trust counter for
each node is determined which can be actively increased and decreased depending
upon the trust value for the purpose of forwarding the packets from source node
to destination node with the help of intermediate nodes. A threshold level is
also predetermined to detect the malicious nodes. If the value of the node in
trust counter is less than the threshold value then the node is denoted
'malicious'. The second part of our protocol deals with the security in the
link layer. For this security reason we have used CTR (Counter) approach for
authentication and encryption. We have simulated all our strategies and schemes
in NS-2, the result of which gives a conclusion that our proposed protocol i.e.
Assured Neighbor based Security Protocol can perform high packet delivery
against various intruders and also packet delivery ratio against mobility with
low delays and low overheads.
