scope:

This specification defines the security architecture, i.e., the security features and the security mechanisms, for the third generation mobile telecommunication system.

A security feature is a service capability that meets one or several security requirements. The complete set of security features address the security requirements as they are defined in "3G Security: Threats and Requirements" (TS 21.133 [1]) and implement the security objectives and principles described in TS 33.120 [2]. A security mechanism is an element that is used to realise a security feature. All security features and security mechanisms taken together form the security architecture.

An example of a security feature is user data confidentiality. A security mechanism that may be used to implement that feature is a stream cipher using a derived cipher key.

This specification defines 3G security procedures performed within 3G capable networks (R99+), i.e. intra-UMTS and UMTS-GSM. As an example, UMTS authentication is applicable to UMTS radio access as well as GSM radio access provided that the serving network node and the MS are UMTS capable. Interoperability with non-UMTS capable networks (R98-) is also covered.

GSM security functions are defined in the TS 43.020 [36].

NOTE: The usage of the authentication management field (AMF) is specified in Annex H and applies for the third (UMTS), fourth (LTE) and fifth (5G system) generation of mobile telecommunication systems.