A Novel Approach against DoS Attacks in WiMAX Authentication Using Visual Cryptography

Denial of Service (DoS) attacks pose a serious threat to wireless networks. In WiMAX a large number of authentication requests sent to the Base Station (BS) by rouge Subscriber Stations (SSs) might lead to a DoS attack. Since authentication involves exchanging and checking certificates of both parties and is a computationally heavy task, the BS would allocate most of its resources for the process of evaluating certificates. An alternative for PKM-RSA is proposed in this paper which uses visual secret sharing in a pre-authentication scenario to avoid DoS attacks caused by the large number of rouge requests. A simple XOR operation is used to check the validity of requesting SS and BS both, thus providing mutual authentication scheme. It not only provides an additional layer of security but also successfully counters the above mentioned problem in the WiMAX authentication.