PDF certificates vs verifiable credentials and Open Badges

The PDF: familiar, printable, and easy to edit

A PDF certificate looks like the paper one: it can be printed, attached to an application and opened on any device. That familiarity is its strength. Its weakness is that it is only a picture of a credential. Anyone with a PDF editor can change a name or a date, and nothing in an ordinary PDF tells the reader that it happened.

A PDF becomes trustworthy when it points somewhere the reader can check: a verification link, a code, or a QR code leading to a page kept by the issuer. The file is the invitation; the check is the proof.

Verifiable credentials: a W3C standard

A verifiable credential is a digital document in a standard shape, carrying claims about someone (who they are, what they achieved, who says so) and a cryptographic proof from the issuer. The W3C Verifiable Credentials Data Model v2.0 became a W3C Recommendation on 15 May 2025. It defines how a credential names its issuer, its subject, when it becomes valid and, optionally, when it stops being valid.

Because the proof travels with the credential, software can check it without asking the issuer's website: the signature confirms who issued it and that nothing has been changed. The digital signatures guide explains what that proof does and does not establish.

Open Badges 3.0: verifiable credentials for learning

Open Badges began as an idea from people at the Mozilla and MacArthur foundations at the 2010 Mozilla Festival. Mozilla launched Open Badges 1.0 in 2013, and IMS Global, now 1EdTech, took over its stewardship in 2017. Version 3.0 reached its final release on 27 May 2024; according to 1EdTech, it aligns with the conventions of the W3C Verifiable Credentials Data Model v2.0.

An Open Badges 3.0 credential describes an achievement (its name, description and criteria), the person who earned it and the organisation that issued it, in a format that badge platforms, wallets and learner records can read.

How revocation works in each

A certificate sometimes has to be withdrawn: an error, a correction, a misconduct finding. How that reaches the reader depends on the format:

• PDF: the file cannot change once downloaded. Withdrawal only reaches readers who check the issuer's verification page.
• Verifiable credential: the credential can name an entry in a status list the issuer publishes. The W3C Bitstring Status List v1.0, also a Recommendation since 15 May 2025, keeps one bit per credential in a compressed list. It uses a minimum length of 131,072 entries so that fetching the list does not reveal which credential is being checked.

Side by side

Which one to issue

Both. The graduate wants a document to print and attach; the employer wants a link to click; an admissions system wants a file it can check automatically. A good issuing system produces all three from the same record, so they can never disagree.

That is how Emitcert works. Every certificate is a printable PDF, a verification page reachable by link or QR code, and an Open Badges 3.0 credential signed with the issuer's Ed25519 key, whose revocation status is published as a Bitstring Status List. The words are fixed when the certificate is granted, so the three formats always say the same thing. For where a graduate can then show it, see adding a certificate to LinkedIn.

In the European Union, the Commission's European Digital Credentials for Learning follow the same idea: Europass describes them as verifiable credentials in JSON-LD, aligned with the W3C standard and sealed by the issuer.