The present invention provides a method for authenticating a user to a network by means of a temporary and/or one-time password. The temporary and/or one-time password is provided by a service provider that can be accessed by means of a mobile telecommunication device. The temporary password is provided on demand, when the user invokes a corresponding access request that is transmitted to the service provider by means of the mobile telecommunication device. The service provider checks and asserts a received access request and generates the temporary password by making use of a dedicated cryptographic method. The generated temporary password is finally transmitted to the personal mobile device of the user that is adapted to transmit the received temporary password to a gateway of a network in order to authenticate the user to the network. Moreover, the mobile telecommunication device provides establishing of an IP-based connection between a user's computing device and the network. The mobile telecommunication device therefore provides establishing of at least two communication links to the network and to the user's computing device. In this way, an authentication procedure can be autonomously performed by means of the user's personal mobile telecommunication device. Installing and/or maintaining authentication related software on the user's computing device therefore becomes superfluous.