An adaptive protocol for efficient and secure multicasting in IEEE 802.11 based wireless LANs

Multicast refers to the technique of sending data to a group of receivers. The use of multicast paradigm in wireless LANs brings significant advantages like savings in channel bandwidth and energy. Considerable research has been done with regard to issues like reliability, but they have not taken into consideration the operation in an insecure environment. We present schemes for secure multicast in wireless LANs, based on the notion of location based access control, wherein only a user present in specific locations can access the services provided. Location based access control is a significant requirement in the pervasive computing environments. These schemes make use of the broadcast nature of the medium for sending encrypted data to a group and for key management. Those schemes which are adaptive to the dynamics of the multicast group perform better than static schemes. Three schemes are presented in this paper. The three schemes vary according to whether the base station shares the same session key with all the members of its cell (SSK) or different session key for each one of the members (SSK), or a combination of the two schemes for efficient key management (Hybrid). The comparative performance of the three schemes based on the results of simulations are presented.