Question: When does the MME include the HashMME information element in a SECURITY MODE COMMAND?
Option 1: During an attach or tracking area updating procedure when the ATTACH REQUEST or TRACKING AREA UPDATE REQUEST message was received with integrity protection and successfully passed the integrity check at the MME.
Option 2: During an attach or tracking area updating procedure when the ATTACH REQUEST or TRACKING AREA UPDATE REQUEST message was received without integrity protection or did not successfully pass the integrity check at the MME.
Option 3: When the UE is initiating a SECURITY MODE COMMAND during an attach or tracking area updating procedure and the ATTACH REQUEST or TRACKING AREA UPDATE REQUEST message was received with integrity protection and successfully passed the integrity check at the MME.
Option 4: When the MME is responding to a SECURITY MODE COMPLETE message from the UE.
Explanation: The HashMME information element is included in the SECURITY MODE COMMAND by the MME during an attach or tracking area updating procedure when the ATTACH REQUEST or TRACKING AREA UPDATE REQUEST message was received without integrity protection or did not successfully pass the integrity check at the MME. This ensures that the UE and MME can establish a secure connection.