The invention relates to a method for planning an automation system project, a method for authenticating a user during access to an automation device in an automation system, an automation system and a computer program for planning an automation system project. To improve the security concept in automation systems, the provision of a single sign-on authentication method for an automation system is proposed. A user is thus able to simultaneously register at all automation devices within an automation project using a single authentication. A fundamental part of the invention is thus to centrally project plan the single sign-on method. In other words, the basic provision of the basis for the subsequent authentication already takes place during the project planning of the automation project based on a project database. This procedure allows the realization of a single sign-on method for the complete projected automation system and thus simultaneously for all automation devices contained in the automation system.