Cellular Network Infrastructure » IMSI Pseudonymization

to not perform it), and particularly at mobility changes across the

MSC/VLR boundary, or even across the PLMN boundary, the TMSI allocated

by the previouis network element may not be known, and an IMSI based

Furthermore, at any given point in time, a legitimate network or a rogue

base station can inquire the IMSI from the ME using the "MM IDENTITY

=== SIM/USIM Provisioning

IMSI pseudonymization as specified by this document works with

onwards).

The initial IMSI provisioned in the SIM/USIM is provisioned as the initial

(initially 1 as in <<hlr-imsi-pseudo-i>>). The new value must be higher,

otherwise the SMS should not be processed further.

timer triggers, EF~IMSI~ of the SIM/USIM is overwritten with the new pseudonymous

IMSI. The TMSI and related data (EF~LOCI~, EF~PSLOCI~) and ciphering keys

(EF~Kc~, EF~KcGPRS~, EF~Keys~, EF~KeysPS~) are invalidated (see 3GPP TS