System aand method for authentication to an application

A method for authenticating a first user in a protected network to an application in a DMZ network shared simultaneously with a second user in an unprotected network. The protected network and the DMZ network are both controlled by a same entity. The first user supplies a userID and a password to a first server within the protected network for authentication for the application. The first server checks authentication of the first user based on the userID and password. If the first user is authentic, the first server forwards to the application an authentication key for the first user and a selection by the first user pertaining to the application. The application checks authentication of the key, and if authentic, complies with the selection by the first user. The second user supplies another userID and another password to the application. If the other userID and other password are authentic, the application complies with a selection made by the second user pertaining to the application.