【正文】 Integrity protection of NAS signalling messages General Integrity checking of NAS signalling messages in the UE Integrity checking of NAS signalling messages in the MME Ciphering of NAS signalling messages NAS security EMM main states in the UE (Spec ) EMM main states in the MME (Spec ) Coordination between EMM and GMM If GMM and EMM are both enabled, a UE capable of S1 mode and A/Gb mode or Iu mode or both shall maintain one mon registration for GMM and EMM indicating whether the UE is registered for packet services or not. A UE that is not registered shall be in state GMMDEREGISTERED and in state EMMDEREGISTERED. If the UE performs a successful attach or bined attach procedure in S1 mode, it shall enter substates and . If the UE performs a successful GPRS attach or bined GPRS attach procedure in A/Gb or Iu mode, it shall enter substates and AVAILABLE. After successful pletion of routing area updating or bined routing area updating and tracking area updating or bined tracking area updating procedures in both S1 mode and A/Gb or Iu mode, if the work has indicated that ISR is activated, the UE shall maintain registration and related periodic update timers in both GMM and EMM. Coordination between EMM and MM UEs that operate in CS/PS mode 1 or CS/PS mode 2 of operation shall use the bined EPS/IMSI attach procedure in order to attach to both EPS and nonEPS services. UEs that operate in CS/PS mode 1 or CS/PS mode 2 of operation and are already attached to both EPS and nonEPS services shall use the bined tracking area updating and periodic tracking area updating procedures. UEs that operate in CS/PS mode 1 or CS/PS mode 2 of operation and are already attached to both EPS and nonEPS services shall perform a bined detach procedure in order to detach for nonEPS services. UEs that operate in CS/PS mode 1 or CS/PS mode 2 of operation should not use any MM timers related to MM specific procedures (. T3210, T3211, T3212, T3213) while camped on EUTRAN, unless the reactivation of these timers is explicitly described. If the MM timers are already running, the UE should not react on the expiration of the timers. GUTI reallocation procedure U EM M EG U T I R E A L L O C A T I O N C O M M A N DS t a r t T 3 4 5 0G U T I R E A L L O C A T I O N C O M P L E T ES t o p T 3 4 5 0The purpose of the GUTI reallocation procedure is to allocate a GUTI and optionally to provide a new TAI list to a particular UE. The reallocation of a GUTI is performed by the unique procedure defined in this subclause. This procedure can only be initiated by the MME in state EMMREGISTERED. The GUTI can also be implicitly reallocated at attach or tracking area updating procedures. The implicit reallocation of a GUTI is described in the subclauses which specify these procedures (see subclause and ). The PLMN identity in the GUTI indicates the current registered PLMN. NOTE 1: The GUTI reallocation procedure is usually performed in ciphered mode. NOTE 2: Normally, the GUTI reallocation will take place in conjunction with another mobility management procedure, . as part of tracking area updating. GUTI reallocation initiation by the work The MME shall initiate the GUTI reallocation procedure by sending a GUTI REALLOCATION COMMAND message to the UE and starting the timer T3450 (see example in figure ). The GUTI REALLOCATION COMMAND message shall include a GUTI and may include a TAI list. GUTI reallocation pletion by the UE Upon receipt of the GUTI REALLOCATION COMMAND message, the UE shall store the GUTI and the TAI list, and send a GUTI REALLOCATION COMPLETE message to the MME. The UE considers the new GUTI as valid and the old GUTI as invalid. If the UE receives a new TAI list in the GUTI REALLOCATION COMMAND message, the UE shall consider the new TAI list as valid and the old TAI list as invalid。 otherwise, the UE shall consider the old TAI list as valid GUTI reallocation pletion by the work Upon receipt of the GUTI REALLOCATION COMPLETE message, the MME shall stop the timer T3450 and consider the new GUTI as valid and the old GUTI as invalid. If a new TAI list is provided in the GUTI REALLOCATION COMMAND message, the MME shall consider the new TAI list as valid and the old TAI list as invalid. U EM M EA U T H E N T I C A T I O N R E Q U E S TS t a r t T 3 4 6 0A U T H E N T I C A T I O N R E S P O N S ES t o p T 3 4 6 0A U T H E N T I C A T I O N R E J E C Ti f a u t h e n t i c a t i o n f a i l e d Authentication procedure The purpose of the EPS authentication and key agreement (AKA) procedure is to provide mutual authentication between the user and the work and to agree on a key KASME (see 3GPP TS [19]). The cases when the EPS AKA procedure should be used are defined in 3GPP TS [19]. The EPS AKA procedure is always initiated and controlled by the work. However, the UE can reject the EPS authentication challenge sent by the work. The UE shall proceed with an EPS authentication challenge only if a USIM is present. A partial native EPS security context is established in the UE and the work when an EPS authentication is successfully performed. During a successful EPS authentication procedure, the CK and IK are puted by the USIM. CK and IK are then used by the ME as key material to pute a new key, KASME. KASME is stored in the EPS security contexts (see 3GPP TS [19]) of both the work and in the volatile memory of the ME while attached to the work, and is the root for the EPS integrity protection and ciphering key hierarchy. Authentication initiation by the work When a NAS signalling connection exists, the work can initiate an authentication procedure at any time. For restrictions applicable after handover or intersystem handover to S1 mode see subclause . The work initiates the authentication procedur