Primary Account Number (PAN)
What it is
The PAN identifies the card: the first 6–8 digits are the BIN/IIN that routes the transaction to the issuer, the last digit is the Luhn check digit. In authorization messages it arrives from the terminal (keyed, swiped, dipped, or tapped); in tokenized transactions the DPAN travels here instead of the real PAN.
PCI DSS treats DE 2 as cardholder data: it must be masked in logs (first 6 / last 4 at most) and encrypted in storage. Network messages may replace it with DE 34 (extended PAN) in rare legacy cases.
Example values
16 4761739001010119LL=16 length prefix followed by a 16-digit Visa test PAN.Specification reference
Defined in ISO 8583:1987 (base). Card networks publish their own dialect tables (Visa BASE I / V.I.P., Mastercard CIS) that refine formats, lengths, and — for private-use elements — the entire layout. Always confirm against the interface specification you implement.