Building Security Gateway

Handheld mobile devices become popular in today´s Internet. The devices have only limited storage and computing capability. The computation power is far below the general purpose device (PC). Small handheld mobile devices may not be able to run this kind of applications due to support of the hardware. Other devices may also not be able to set up the secure session due to the support of client software. In this paper, a secure architecture is proposed in the building SIP network environment. A special appliance, called Building Security Gateway (BSG), is designed to help small handheld mobile devices to perform security functions on Voice over IP, such as setting up a secure session and encrypting/decrypting contents similar to a desktop PC. A prototype BSG is built in the SIP network. SIP-based VoIP session mobility between UAs is performed with the help by BSG.