Marcus Hale
Senior Payment Systems Analyst. Twelve years across card networks, payment security and transaction processing, covering issuer-side configuration, acquirer routing and the standards that govern card data.
What I cover
I write and review everything published on this site. My work focuses on the parts of card payment that are genuinely technical: how identifiers are allocated, how record formats are structured, what each validation layer actually proves, and where the boundaries sit between what a tool can confirm and what only an issuer can confirm.
Experience
- Card networks — identifier allocation, application identifiers, record structure and interchange rules across Visa, Mastercard, American Express and Discover.
- Payment security — PCI DSS scope, tokenisation, 3-D Secure enrolment and challenge behaviour, and the fraud controls issuers actually apply.
- Transaction processing — authorisation flows, response code interpretation, clearing and settlement, and chargeback handling.
- Data quality — maintaining BIN datasets, spotting stale allocations and building validation that catches the errors a simple checksum misses.
Standards I work from
- ISO/IEC 7812 — identification of card issuers, the structure behind IIN and PAN
- ISO/IEC 7813 — magnetic stripe record formats, Track 1 and Track 2
- ISO/IEC 7816-4 — application identifiers and record structure
- EMVCo Book 3 — chip application specification, TLV data objects and cryptograms
- PCI Security Standards Council — PCI DSS and the surrounding supporting documents
Editorial approach
Every page is written to answer a question rather than to occupy a keyword. Where a standard is the authority, I cite it. Where a dataset is the source, I name it and state its limits. Where my own judgement is involved, I say so. The editorial standards spell this out in full, and data sources documents exactly where each dataset comes from.
Corrections
Card standards move, and allocations change. If something here is out of date or wrong, tell me with the page URL and the correction. Verified fixes are applied and the page's last-updated date is refreshed.