PDF UtilitiesPDF SecurityFree Tool

Verify PDF Signature

Check whether a digital signature on a PDF is cryptographically valid, whether the certificate is trusted, and whether the document has been modified after signing.

How to Use Verify PDF Signature
  1. 1Upload the PDF containing the digital signature you want to verify
  2. 2The tool reads all signatures embedded in the PDF
  3. 3Each signature is checked for validity, certificate trust, and document integrity
  4. 4Results are shown: Valid (green), Invalid (red), or Untrusted Certificate (yellow)
  5. 5Review the signer details and certificate information for each signature
Examples
  • Verify that a signed contract PDF has not been modified since signing
  • Check whether a digitally signed regulatory document is authentic before processing
  • Confirm the validity of a digital signature on a received invoice before payment
  • Verify a signed software agreement PDF before countersigning
Frequently Asked Questions

Verification checks three things: (1) the signature is cryptographically valid for this document, (2) the certificate used to sign has not expired, and (3) the document content has not been modified since signing.

It means either the document was modified after signing, the certificate is expired or revoked, or the signing certificate is not trusted by the verification system.

A digital signature creates a hash of the document content at the time of signing. Verification recalculates the hash — if it differs, the document was changed and the signature is invalid.

The signer used a self-signed or unrecognised certificate. The signature math may be valid, but you cannot confirm who the signer is without a trusted Certificate Authority backing the certificate.

Yes. The tool checks all signatures in the document and reports the validity status of each independently.

Yes. Verification runs in your browser. Your PDF is never uploaded to any server.

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