SIP end-to-end security between Ipv4 domain and Ipv6 domain

The session initiation protocol (SIP) carries the endpoint IP addresses, as part of its message format. When one end-point is in an IPv4 addressing domain, and the other is in an IPv6 addressing domain, a NAT-PT gateway must be used at the network level, to translate the protocol headers. The message bodies are altered by an application level gateway (ALG), to reflect the changed addresses. However, this alteration causes end-to-end security mechanisms to fail. We describe a proposal for a SIP end-to-end security mechanism between IPv4 networks and IPv6 stub domains, which overcomes the failure. We have validated the proposal using the PROMELA formal specification language and the SPIN validation system.