TINA is a specification of an open architecture for telecommunication services in the broadband, multimedia, and information era. Its characteristics most relevant for security are a variety of services, a multitude of service providers, a well defined business model, a middleware platform for service development and provision, and the assumption of advanced costumer premises equipment. Concepts for its security architecture are developed in the CrySTINA project. We introduce the TINA-C architecture, analyse it with regard to security, and present the CrySTINA security architecture. CrySTINA is aligned with the OMG`s CORBA Security specification, but enhances it with regard to security interoperability despite the heterogeneity of security policies and technologies that must be expected in TINA networks. Thus, we present a model for the enforcement of security policies that supports the negotiation of security contexts.