The Cripto project architecture: a Spanish experience in broadband networks security

The Spanish broadband program (PLANBA) coordinates several research projects in broadband communications. This paper is focused on one of these projects, called Cripto, designed to provide secure communications between multimedia terminals joined to the PLANBA (B-ISDN) network. The architecture of the security system, as well as the logical placement of the security services, has been chosen according to the multimedia terminal architecture. We also present the key-management protocol proposed as a result of our work in the Cripto project. The threats to be protected against, the number of users in the network, their behaviour and the cost that we are willing to assume are the main considerations to correctly devise these protocols. The definition of the most suitable protocol has been closely related with the cryptographic operator previously selected