DYNAMIC DISTRIBUTED CERTIFICATION AUTHORITY FOR MOBILE AD HOC NETWORKS

Abstract

A Mobile Ad Hoc Network (MANET) is an infrastructureless network of wireless mobile nodes that cooperate among each other to maintain network connectivity. Infrastructure less networking technologies like MANET provide ubiquitous networking service to the 'users. Securing a MANET is challenging and much more difficult in comparison to infrastructure-based networks. Use of error prone wireless channels, node mobility and dynamic node membership makes a MANET more vulnerable to :security theeffective ways of securingaMANET is by using Public Ke"ftf •i rYp icates%are issued by a trusted entity termed as Cryptography and Certificates. _✓` Certificate Authority or Certification Authority. For a wired network, centralized approach for CA is pre, . used for a MANET as the scalability and availability is ret researchers have proposed design of a Distributed CA for a MANE'i, Cryptography. With a distributed CA, a node obtains the certification servo,. communicating with its one-hop neighbors. However, when the number of nodes in the network reduces, there is a substantial increase in delay experienced in obtaining the certification service. In this dissertation, we propose a protocol suite MANETMonitor, which prevents an increase in the certification service delay experienced by the nodes. MANETMonitor monitors the Average Node Degree of a network by obtaining node degree (number of neighbors) information from all the nodes in the network. When the number of nodes in the network reduces, MANETMonitor causes an appropriate change in the Threshold value thereby preventing an increase in the certification service delay. The performance of the protocol has been evaluated varying the number of nodes and length of cryptographic keys. Simulations were done using NS2 a discrete event network simulator and cryptographic routines were written in C++ using OpenSSL an open source cryptography library.