Format: bLength: 8Fixed length
DE 52
PIN Data
What it is
The PIN never travels in clear: the PIN pad forms an ISO 9564 PIN block (format 0 XORs the PIN with the PAN; format 4 is AES-based) and encrypts it under the zone PIN key — commonly a DUKPT-derived key. Each hop of the network translates the block from one zone key to the next inside an HSM; the issuer (or its HSM) finally verifies it against PVV or IBM 3624 offset.
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.