The rapid increase of interest in Internet, the Web, and Electronic Commerce raises a number of security issues. The main issues are usually listed as confidentiality, integrity, privacy, authentication, non-repudiability, authorisation, and auditing. Whereas the establishment of PKI s at the level of closed systems individual organisations is now routine, significant problems remain to be solved at the level of open systems, slowing down the wider adoption of PKI in industry. Important as it is, however, in many Internet applications strong authentication mechanisms is not the goal by itself.
Authentication is needed to support other functions such as authorisation and auditing .
Authorisation and auditing mechanisms for distributed systems is currently a very active field of research. The ACL model was originally designed for access control decisions in closed systems. The requirement is that a server knows in advance the identities and the permissions of its clients. Such information is recorded in an ACL that is centrally administered. The ACL model, however, is fraught with problems, in particular as systems scale up and become deployed in increasingly open contexts.