Design of Modified CGA for Address Auto-configuration and Digital Signature in Hierarchical Mobile Ad-Hoc Network

The CGA (Cryptographically Generated Address) is designed to prevent address spoofing and stealing and to provide digital signature to users without certification authority or any other security infrastructures, but fake key generation and address collision appear in flat-tiered network. To solve these critical problems, CGA defines security parameter (SEC), which is set to high value when high security is required and vice versa. Although CGA with high SEC makes attackers be difficult to find fake key and to try address stealing, it brings an alarming increase in processing time to generate CGA. On the contrary, the probability to find a fake key is high if low SEC is applied to CGA. We propose modified CGA (MCGA), which is proper to mobile ad-hoc network. The proposed MCGA has shorter processing time than CGA and offers digital signature with no additional overheads. We have settled fake key and address collision problems by employing hierarchical network structure. The MCGA is applicable to as well public networks as ad-hoc networks. In this paper, we design mathematical model to analysis processing time for MCGA and CGA firstly and evaluate processing time via simulations, where processing time for MCGA is reduced down 3.3 times and 68,000 times, compared to CGA with SEC 0 and SEC 1, respectively. Further, we have proved that CGA is inappropriate for both ad-hoc networks and public networks when SEC is 3 or bigger than 3.