Question: What is the purpose of the "tag" element in the modifiedDataToIntegrityProtect object added by the first Roaming Intermediary?
Option 1: To identify the type of modifications made by the Roaming Intermediary.
Option 2: To authenticate the source of the modifications.
Option 3: To provide a unique identifier for the message.
Option 4: To act as replay protection for updates made by the first Roaming Intermediary.
Explanation: The "tag" element is copied from the JWE object generated by the cSEPP and serves as replay protection for updates made by the first Roaming Intermediary. This ensures that any modifications made by the Roaming Intermediary cannot be replayed or reused, providing an additional layer of security in the message flow between SEPPs.