The Master Address File Auxiliary Reference File (MAF-ARF) is a Census Bureau file that contains a Master Address File Identifier (MAFID) and a protected identification key (PIK). The MAFID is drawn from the MAF. The PIK is a resulting field from the validation of a record Social Security Number (SSN). At the completion of the PVS validation process, the SSN is replaced with PIK as a form of anonymization of the record.
