Authentication And Key Management Mechanisms In Mobile Ad Hoc Networks

Mobile Ad hoc network has become the most important communication style as it does not need fixed infrastructure, can be installed quickly and is hard to destroy. Because Ad hoc network is opening and used in military affairs, it is very important to ensure its safety, and the focus is to provide authentication and key management services.In traditional networks, authentication and key management services are mostly provided by Key Distribution Centers (KDC) or Certificate Authorities (CA). But it is problematic to establish a key management service using a single CA in Ad hoc networks. The CA is a vulnerable point of the network: if adversaries capture the CA, the whole system is paralyzed. So new schemes have to be studied.Two-level Distributed Certificate Authority using threshold signature to distribute the trust from a single CA to a set of nodes by letting these nodes share the key management responsibility and provide authentication services commonly, made the system safety and easy to extend.Integrity and non-repudiation of certificate information is achieved by asymmetric cryptography. Certificate may be updated or withdrawn, which make it more validity. A efficient and secure algorithm for collector decision is proposed and used in certificate update. Secret key shares are refreshed periodically, thus the adversary is challenged to compromise t servers between periodic refreshing, where t is a threshold. Share refreshing is transparent to all nodes.Key exchange using certificate makes the communication confidentially, integrated and non-repudiated.