Secure smart phones fitted to mobile Ad hoc networks and devices for security control

The presence of wireless links makes mobile ad hoc networks more vulnerable than wire-line networks to various forms of attack. Multimedia session communication applications over such ad hoc networks need a session key to encrypt session call traffic. This security requirement for session communications can be fulfilled by applying dynamic session key management architecture. In this paper, we propose a key agreement scheme that can be realized by encrypting mobile traffic with the agreed secret session key. We also propose a key control device (KCD) that can legally listen to any session call. We solve these contradictory sounding goals: encrypting call traffic and monitoring call traffic. The key agreement process forces a pair of call participants to calculate the Diffie-Hellman session key just before a call session begins. It starts by sending an SMS message for announcing its temporary IP address (TIP) and `nonce´ from the caller to the callee, so that the callee may learn the caller´s TIP immediately at the beginning of each call and send a `GET/nonce´ command in an HTTP request line to perform the Diffie-Hellman public key exchanges with the caller. The nonce value will be used to prevent replay attacks and to thwart clogging attacks. In the proposed security control, one of the call pair is designated to report call information so that the KCD may compute the same secret session key as the call pair agree on.