Authentication in a Multi-access IMS Environment

The standard ISIM-based authentication mechanism of IMS is only intended for mobile phones and cannot be used for fixed IMS clients on stationary devices without SIM cards. This paper presents the authentication schemes dedicated for fixed IMS clients. Such schemes are necessary in order to extend the usage of IMS to fixed environments. Authentication solutions for other applications than the IMS client are also described. These applications are assumed to be located on the same stationary device as the IMS client, and might for example be browsers, contact lists and email clients. Finally, a single-sign-on mechanism is proposed. It is designed to simplify the authentication process without compromising the security.