Abstract
With the increase of mobile and wireless communication in heterogeneous networks, the need for security has also increased. Mobile devices have to execute seamless and secure handover from one type of network to another. But before the actual execution, some security measures needs to be taken against denial of service and replay attacks. These measures require lengthy procedures for authentication and authorization, which causes long delays in handover execution. In this paper we have proposed an adaptive approach for Secure Seamless and Soft Handover (S3H) between WiMAX and 3G Networks. The idea is to use make-before-break approach to achieve pre-authentication with minimal security requirements before actual handover execution. This approach is intended to achieve security with less delay as compared to hard handover approach.