Single sign-on secure service access

This invention relates in general to authentication, authorisation, and access control, and more specifically to a method and a system for general Public Key Infrastructure based authentication allowing users to have only one electronic ID for secure access to all services. The system described advances the state of the art by providing general, PKI-based authentication. By offering validation and possibly also authorisation services to other service providers, the system can provide an infrastructure for general, PKI-based authentication, handling electronic IDs from in principle any issuer of such.