ISDN Security Services
Herbert Leitold, Karl Christian Posch, Reinhard Posch · 1999
Analog and digital plain old telephony service (POTS) is increasingly replaced by technologies that integrate voice, data, and video communication services. The integrated services digital network (ISDN) offers the embedding of this advanced multimedia communication into the subscriber loop. Nowadays widely available, ISDN builds a promising approach to improve company’s, public authority’s, or individual’s telecommunication facilities. However, a secure means of transferring sensitive information in any publicly accessible communication infrastructure is a major concern. In particular, authenticated and confidential communication is of paramount importance. In this paper, we describe the implementation of a paradigm where advanced security services are offered by the ISDN infrastructure as an additional service. The encryption model is based on transparently integrating the security devices into the ISDN network termination (NT). This makes the approach independent from both the terminal equipment (TE), and the service used, as well as independent from the ISDN switches and exchanges installed by the service provider. The paper discusses integration of the security device into the ISDN architecture, as well as the design of a data encryption standard (DES) TripleDES encryption unit being the buttress of the ISDN security solution. Comparisons to related work and products in the field are made and the relation of the project to the broadband pendant to ISDN—broadband-ISDN (B-ISDN)—is sketched.