name: MSIN
full_form: Mobile Station Identity Number
context: need to retrieve an IMSI. The other 64 bits are split in 48 bits, in which the 36-40 bits MSIN part of the new IMSI is encrypted, and 16 bits random value. As stated in option A, choice of functions must be in a way that also the SMAC and the concealed MSIN look random. To conceal the MSIN part, USIM and HSS create a shared key to allow the efficient encryption of the MSIN part within the max 40 bits (padded to 48 bits). This symmetric encryption key EK is generated by applying f5 to SQN and K. EK is xor-ed with the MSIN of the selected IMSI to create a concealed MSIN. The result is concatenated with the 16 bit random and 64 bit SMAC. Considerations It needs to be noted that the RAND calculation as done in the proposed solution of [100] (see option B): "RAND = 64 bits SMAC || 16 bits random || 48 bits concealed MSIN" may allow to correlate the subscriber with the received (and possibly re-sent) RANDs, when SMAC and MSIN are included within the RAND. In case recovery is required
description: The Mobile Station Identity Number (MSIN) is a critical network attribute used in telecommunications to uniquely identify a mobile station. It is part of the International Mobile Subscriber Identity (IMSI), which is encrypted and concealed for security purposes.
explanation: The context explicitly mentions MSIN as a 'part of the new IMSI' that needs to be encrypted, indicating its role as an identifier within the network. This classification is justified by the emphasis on concealing the MSIN part for security reasons.
section_title: 5.7.4.18.2	Solution details
biotag_Context: O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Parameter,O,O,O,O,B-Parameter,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Parameter,O,O,O,O,O,B-Parameter,O,B-Device,O,B-Network Function,O,O,O,O,O,O,O,O,O,O,O,B-Parameter,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Parameter,O,O,O,O,O,O,O,B-Parameter,O,O,O,B-Parameter,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Parameter,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Parameter,O,O,O,O,O,O,O,O,O,O
biotag_Description: O,B-Parameter,I-Parameter,I-Parameter,I-Parameter,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Parameter,I-Parameter,I-Parameter,I-Parameter,O,O,O,O,O,O,O,O,O