@conference{giorgos-fabio1, author = "Giorgos Karopoulos and Fabio Martinelli", abstract = "Multimedia applications have made their way to the wireless/mobile world and this is not likely to change. However, people have not stopped using multimedia services through wired networks and this is also something that is not foreseen to change. What really is changing in the coming networks is the separation of network and service providers; this separation is creating new security challenges since the end user does not have the same trust relationships with all these providers. This paper proposes an architecture for protecting end users from untrusted and unreliable multimedia service providers in Next Generation Networks (NGNs) that utilize the IP Multimedia Subsystem (IMS) for multimedia delivery. Our proposal is based on the Usage Control (UCON) model for monitoring continuously the multimedia content delivered to the end user and ensure that it is the proper content requested by the user.", booktitle = "Secure and Trust Computing, data management, and Applications (STA 2011)", doi = "10.1007/978-3-642-22339-6_9", note = "NESSoS; CNR; no tier; citations 2", publisher = "Springer", title = "{IMS} {S}ession {M}anagement {B}ased on {U}sage {C}ontrol", year = "2011", }