Abstract: Disclosed is a method for providing a user access to a computer system comprising a plurality of services and a plurality of authentication levels, the method comprising dynamically monitoring a risk profile of a user authenticated on said computer system; dynamically selecting an authentication level for each of said services based on said monitored risk profile; and if said authentication level for a service is higher than an actual authentication level for said user, sending a further authentication request to the user requesting the user to provide authentication information corresponding to the dynamically selected authentication level upon said authenticated user requesting access to said service.