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Check a signature

Is this PDF really signed?

Drop a signed PDF to see who signed it, when, and whether anything changed since. The check runs on this device: your file is never uploaded.

Check it in Adobe Acrobat

Acrobat checks the signature on its own. Trust the Prson Root CA once on your computer, and every Prson-signed PDF then shows "Signature is valid" with the signer's name.

  1. Download the Prson Root CA (prson-root-ca.cer).
  2. In Acrobat, open Edit → Preferences → Signatures (on a Mac: Acrobat → Settings → Signatures).
  3. Under Identities & Trusted Certificates, choose More…, then Trusted Certificates → Import, and pick the file.
  4. Before you accept, check that its SHA-256 fingerprint is loading….
  5. Select it, choose Edit Trust, tick Use this certificate as a trusted root (nothing else), then OK.
  6. Reopen the PDF. The signature panel shows the signer, the time and "Signature is valid".

Why the extra step: Prson's root isn't on Adobe's Approved Trust List yet, so Acrobat shows an unknown signer until you trust it. Preview on a Mac and browser PDF viewers don't check signatures at all; use this page instead.

What a Prson signature means

  • The signer read the chip of their passport or ID card with the Prson app, and the name on the certificate is the one on that chip.
  • The signature was made on the signer's phone, with a private key Prson never receives.
  • Any change to the signed content breaks the signature, here and in Acrobat.
  • It's an advanced electronic signature under the EU eIDAS rules, not a qualified one.