A certificate delivered as a PDF — even with a scanned signature and a seal — has a structural problem: it is an editable file. Whoever receives it cannot tell the original from a doctored copy, and the only way to check is to email or call the issuer. In international professional mobility, where a certificate crosses three countries and four agencies, that means almost nobody checks almost anything.

Verifiable credentials flip the burden: validity doesn't live in the file. It lives at the source.

A PDF is a photo, not proof

Altering a PDF with an editor takes minutes: crop a signature, change a name, adjust a date. Verifying it through the traditional channel — an email to the issuing body — takes days or weeks, when they answer at all. The asymmetry is total: forging is cheap, checking is expensive. That is why paper and PDFs circulate on faith.

What a verifiable credential is

When a case file is completed, Booka issues a certificate with a unique code and a QR. The document can be printed and passed around like any PDF — but the claim of validity isn't on the paper: it's on a public verification page that answers against Booka's registry in real time.

The principle: validity is confirmed by the source, not by a file anyone can edit.