Document fraud almost always surfaces late: after the candidate is hired, or after the file has been submitted to the regulator. It surfaces late because the usual check — a human looks at the PDF and it "seems fine" — verifies nothing. It validates the look of a document, not its authenticity.

This guide walks through the red flags that give away a manipulated diploma or passport, and how Booka's Verifier Agent catches them automatically before a file moves forward.

Why visual review fails

A forged document competes against a reviewer who sees dozens of files a day, in formats from more than 30 countries. Nobody remembers which seal a specific university uses or how an apostille issued in another country is structured. Visual review catches the crude forgeries; the careful ones pass.

The alternative is not to look harder. It is to read the document and compare it against what it should contain — which takes three pieces: data extraction (OCR), a registry of requirements per country and profession, and rules that compare the two.

Red flag 1 — The passport check digits don't add up

The MRZ band (the two lines of characters at the bottom of a passport) is not decorative: it follows the ICAO 9303 standard and carries mathematical check digits, computed with a 7-3-1 weighting over each field — document number, date of birth, expiry date.

That enables two things:

  • If the passport number doesn't match its check digit, there is either a transcription error or a manipulation. A passport with a tampered MRZ : the digits stop adding up.