Abstract: A method for establishing a link key between correspondents in a public key cryptographic scheme, one of the correspondents being an authenticating device and the other being an authenticated device. The method also provides a means for mutual authentication of the devices. The authenticating device may be a personalized device, such as a mobile phone, and the authenticated device may be a headset. The method for establishing the link key includes the step of introducing the first correspondent and the second correspondent within a predetermined distance, establishing a key agreement and implementing challenge-response routine for authentication. Advantageously, main-in-the middle attacks are minimized.

Abstract: The method operates in a wireless code division multiple access (CDMA) communication system (10) which includes a fixed communication unit (114). The fixed communication unit has a plurality of paging channels (230, 235) and a plurality of traffic channels (245, 247). A mobile communication unit (320) is responsive to the fixed communication unit via an active paging channel of the plurality of paging channels. The method includes selecting a paging channel of the plurality of paging channels over which to transmit the message to form a selected paging channel (410); transmitting a preliminary message via each of the plurality of paging channels (415), the preliminary message comprising the selected paging channel; and transmitting the message over the selected paging channel (425), the mobile communication unit receiving the message over the selected paging channel while continuing to monitor the active paging channel.