name: XMAC-I
full_form: Expected MAC used for data integrity of signalling messages
context: derives KBS from the KRBS and <bsGKI, bsGNI> as described in sub-clause 6.9.2.2.3, and then calculates the XMAC-I based on KBS as the same that gNB computes MAC-I based on KBS, 6. The USIM returns the XMAC-I to the ME. The ME compares XMAC-I with MAC-I. If they are equal, the ME handles the broadcast message. Otherwise, the ME marks the cell as high-risk cell in cache. NOTE 2: The serving network may update the KRBS without notifying the UE, in this case, the MAC-I verification fails but gNB is genuine. If all the cells around the UE are marked as suspect cell or high-risk cell, the UE may start a verification timer. When the verification timer is timeout, the UE should be ready to perform registration procedure. If the UE is ready to send an initial NAS message before timeout, the UE should stop the verification timer. When the UE is ready to send an initial NAS message (due to timeout or not), the UE should try to send the initial NAS message via the suspect cells one by one then
description: XMAC-I refers to the Expected MAC used for data integrity of signalling messages. It is derived from KBS and compared with MAC-I to verify the authenticity of broadcast messages.
explanation: The text describes XMAC-I as a calculated value ('derived from KBS') used for verifying message authenticity, aligning with the definition of a parameter.
section_title: 6.9.2.3.1	Security procedure for broadcast messages
biotag_Context: 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-Network Function,O,B-Parameter,O,O,O,O,O,B-Device,O,O,B-Parameter,O,O,O,O,B-Network Function,O,B-Parameter,O,O,O,O,O,O,O,B-Network Function,O,O,O,O,O,O,B-Network Function,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,B-Network Function,O,O,O,O,O,O,O,O,B-Device,O,O,O,O,O,O,O,O,O,B-Device,O,O,O,O,O,O,O,O,O,O,O,O,B-Device,O,O,O,O,O,O,O,O,O,B-Device,O,O,O,O,O,O,B-Protocol,O,O,O,O,B-Device,O,O,O,O,O,O,O,B-Device,O,O,O,O,O,O,B-Protocol,O,O,O,O,O,O,O,B-Device,O,O,O,O,O,O,B-Protocol,O,O,O,O,O,O,O,O,O
biotag_Description: B-Parameter,O,O,O,O,B-Protocol,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Parameter,O,O,O,O,O,O,O