Security analysis of user mobility in triple-play systems

Users of triple-play systems expect to be able to use their services on different locations. That opens an issue of extending security to include mobile triple-play users. Mobile users need to authenticate to the system and vice-versa. Users expect confidentiality of their communications. Content providers request copyrights to be respected. Protocols for session control, SIP. and media transfer, RTP, have their secured versions, SIPS and RTSP. That solution would require multiple protocols and keys and would be a burden on users and system administrators. This paper proposes an architecture that uses IMS to provide services and VPN to secure them. IMS provides convenience of user mobility. VPN provides authentication, confidentiality and integrity. Additional security provided by VPN does not translate to additional work for users, It is completely transparent for them. Proposed design is implemented and tested. IMS with different services was available, through VPN, to mobile users connected to the Internet with different devices and connections. The testing confirmed security and usability for mobile users.