The separation of user and control planes and the access and non-access stratums in LTE/SAE result in an implicit security requirement. 3GPP describe an extensive two layer security architecture that also utilizes IETF security solutions for its IP core. The security architecture is maintained in LTE-Advanced, with some enhancements concerning more capable encryption and integrity algorithms being utilized.
This chapter is organized as follows. Section 14.1 offers the rationale behind the design of 3GPP's security architecture for both LTE and LTE-Advanced. Section 14.2 describes the security architecture, including security features defined by the standard for network access and domain, user domain, application domain and the visibility and configurability of security. The key hierarchy in EPS is relevant to LTE, and is hence explained in Section 14.3, while the relationship between the UE states and state transitions and securities are outlined in Section 14.4. Finally, Section 14.5 describes the security procedures that take place between the UE and elements at the network core.