FASC-N (Federal Agency Smart Credential Number)

The federal-issued identifier embedded in a PIV credential, defined in NIST SP 800-73 and FIPS 201. FASC-N is a 75-bit (extended) or 200-bit (full) structured number combining Agency Code, System Code, Credential Number, Credential Series, Individual Credential Issue, Person Identifier, Organizational Category, Organizational Identifier, and POA (Person/Organization Association).

FASC-N appears inside chuid wrappers — readers and panels validate the FASC-N portion against trust lists provisioned by the issuing authority. The numbers are long enough that traditional PACS card-number fields (32-bit unsigned integer ceiling, e.g. CCURE 9000's 4,294,967,295 limit) cannot hold the full FASC-N — those deployments must use the CHUID + FacilityCode credential-unique-fields path.