Transitive trust in mobile scenarios
  Horizontal integration of access technologies to networks and services should be accompanied by some kind of convergence of authentication technologies. The missing link for the federation of user identities across the technological boundaries separating authentication methods can be provided by trusted computing platforms. The concept of establishing transitive trust by trusted computing enables the desired crossdomain authentication functionality. The focus of target application scenarios lies in the realm of mobile networks and devices. 
Nicolai Kuntze and Andreas U. Schmidt