Carrier specific unique member IDs (ME107, MC137, PC107, DC056) and/or carrier specific unique subscriber IDs (ME117, MC141, PC108, DC057) are masked prior to the fulfillment of data requests. Therefore, the original ID value provided by the SE is not visible to the data requestor. ID values are masked consistently to ensure accurate ID linkages over time. This requirement applies to the associated Alias ID fields (ME107A, ME117A, MC117A, MC141A, PC107A, PC108A, DC056A, DC057A).