ed by 3GPP 31.111 which also includes specifications of USIM Application Toolkit (USAT) for 3G networks [4]. 10.5.3.2 Key UICC Standards Figure 10.10 shows the key UICC standards that have been developed by 3GPP and ETSI (Smart Card Platform). At a high level this specification can be divided into basic, authentication, testing, and Java card categories. 10.5.3.3 UICC in IMS and EPS The UICC, as per existing standards, has become an IP connected processor with its own IP layers and IP stack. This means that it is ready for deployment in all IP networks such as LTE and IMS (IP Multimedia Subsystem) platforms. The Smart Card Web Server (SCWS) is an application execution environment to develop interoperable and portable operator applications that run on the USIM. Recently standardized by OMA, the SCWS leverages the handset browser to run offline applications as the cards host a real web server. The SCWS communicates with the handset using the USIM IP stack. The UICC can be considered as the trusted operator anchor in the user domain in EPS (E-UTRAN and EPC). The EPC (Enhanced Packet Core) flat and open architecture brings security risks that must be mitigated by deploying highly secure and tamper proof devices in the user domain. Thus, UICC role will become more significant in providing secure services for EPS networks. Co-existing on the same UICC platform with the USIM application is the ISIM - IP Multimedia Services Identity Module which provides access to the IMS via any IP access network. The ISIM is an UICC Application providing authentication computation for SIP authentication. It contains files dedicated to SIP and algorithm for user authentication on the network. The ISIM also includes IMPI (IMS private identifier), at least one IMPU (IMS public identifier), authentication key, and SO on [20,21]. 9 Electrically Erasable Programmable Read-Only Memory is a type of non-volatile memory used in phones. Next Generation Mobile Communications Ecosystem Testing TS 31.120 TS 31.048 SIM/USIM Interworking TR 31.900 Too