How to check a PDF's digital signature: a step-by-step guide

Opdateret 2. oktober 2026

Denne vejledning findes endnu ikke på dansk, så den vises på engelsk. Selve værktøjet fungerer på dansk.

A signed contract, an e-invoice, a land-registry extract: Verify PDF Signature checks every digital signature in a PDF - that the signed content is unchanged, that the signature matches its certificate, what was added afterwards, who issued the certificate and whether that provider is on the EU trusted lists or the U.S. Federal PKI. It makes no file and costs nothing from the daily limit. It all happens in your browser; nothing is uploaded.

Prøv gratis, uden konto: dine filer forlader aldrig din enhed.

Åbn Valider PDF-signatur

Kort fortalt

  1. Drop the signed PDFs on the page, or press Add files.
  2. Each file is checked as it arrives; the list says intact, needs a look or not valid.
  3. Read the card of each signature in the middle.
  4. If the file changed after signing, save the version that was signed.

Add the files

Drop the PDFs anywhere on the page, or press Add files. Every file is checked the moment it arrives. The list gives a one-word verdict - intact, needs a look, not valid, or no digital signature - and the middle shows the selected file's report, with a card for every signature.

Verify PDF Signature with three files: the signed lease agreement marked 1 signature, needs a look; the other two have no digital signature

Read the signature card

At the top of a card is the verdict - "Intact - not changed since signing" is what you hope for - and the signer's name. Under it: when it was signed (and by whose clock), the reason and place, the page the signature sits on, who issued the certificate and how long it is valid, the algorithm, the format and level (PAdES B-B to B-LTA), the trust list, and the certificate chain.

A signature card: intact, not changed since signing, signed by Jordan Ellis, with a warning that the certificate is self-signed, and its details
Intact, with a warning: a self-signed certificate proves the file hasn't changed, not who signed it.
  • Warnings say what to look at: a self-signed certificate, a certificate that wasn't valid at the signing time, a weak hash, content added after signing that no signature covers.
  • Trust list: a provider on an EU trusted list (with its status at the signing time) or the U.S. Federal PKI is named; a qualified electronic signature or seal is labelled as such.
  • Revocation: what the file itself carries - OCSP answers and revocation lists - is checked.

When the file changed after signing

If content was changed after a signature, the card offers Save the signed version - the file exactly as it was when that signature was made - and Compare with the current version, which opens the two side by side in Compare PDFs to show what changed.

Not checked here: providers that are only on other lists, such as Adobe's, and revocation online when the file carries no data. The rail lists what is and isn't checked.

Limits

Checking makes no file and doesn't count against the daily limit, with or without an account.

What next?

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Åbn Valider PDF-signatur

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