To secure interactive multimedia applications in wireless LANs WLANs it is pertinent to implement a number of security services such as authentication, key exchange and real-time encryption decryption. WLANs, though, present a complex and challenging environment for implementing such security services since these services may deplete the limited network resources and increase the burden of supporting quality of service for multimedia applications. Consequently, a broker is needed to mediate proper security considering inputs such as user security requirements, user security literacy, available network resources, and security routines performance. In this paper we introduce a Security Broker that we have designed to ful ll these complex mediation needs. This broker is implemented in software and tested in a wireless LAN testbed. The reported security broker design and implementation considers the wireless LAN environment as well as the multimedia applications' quality of service re...