There are solutions available today to secure intra-domain VoIP traffic. This same type of security capability is needed to support cross-domain voice collaboration applications. Avenda Systems proposes a secure inter-domain collaboration enabling solution called SIDCO (Secure Inter-Domain Collaboration). SIDCO system will provide the architectural foundations to support all intra- and inter-domain secure collaboration requirements. SIDCO system will make use of standards as put forth by Internet Engineering Task Force (IETF) and International Telecommunication Union - Telecom (ITU-T) Internet telephony standard bodies. Adhering to these standards also ensures that the proposed solution is interoperable with the large assortment of existing VoIP applications. Avenda Systems has the expertise to develop a practical and highly effective secure inter-domain collaboration system. Organizations, both military and civilian enterprises, can use this system to enable and secure their inter-domain collaboration. The technologies employed in this product are practical and innovative and have not been implemented in commercially available comparable products. Prototype development in Phase I will provide the knowledge and foundation for building a complete product in Phase II, and a commercially viable product in Phase III.