Closed Administrative Domains

Supplementary section for Chapter 1 of Understanding Networked Applications: A First Course, Morgan Kaufmann, 1999. Copyright notice: Permission is granted to copy and distribute this material for educational purposes only, provided that this copyright notice remains attached. The security techniques described thus far are well suited to a public environment, like consumer electronic commerce. The asymmetric encryption algorithm supports authentication, integrity, and confidentiality, without the hassles of distributing secret symmetrical keys. The price paid— which raises its own set of issues—is the need for a certificate authority and digital certificates. In a closed administrative domain, the infrastructure of digital certificates can be avoided by distributing secret symmetrical keys directly to users or hosts. This enables a class of authentication, access, and confidentiality protocols based on a shared secret—the presumption that two or more entities (users or hosts) share a common secret. This shared secret can be used for both authentication (using a challenge-response protocol) and confidentiality.