Check if a PDF Is Digitally Signed

• A signature IMAGE on the page is not a digital signature — the real thing lives in the file structure
• Digital signatures can be invisible: no mark on any page, yet fully signed and verifiable
• The checker reads the PDF structure directly and answers definitively: signed or not
• If signed, you also get the signer, certificate issuer, timestamp, and integrity status
• Nothing is uploaded — detection runs entirely in your browser

Frequently Asked Questions

How do I know if a PDF is digitally signed or just has a signature image?

Drop it into the checker above — it reads the PDF's internal structure. A digital signature shows up with the signer's certificate and timestamp; a signature image shows up as nothing, because images aren't signatures. Visually you often cannot tell the difference, which is the point of checking structurally.

Can a PDF be digitally signed with nothing visible on the page?

Yes — invisible signatures are common and fully valid. The signature is a data object in the file; the visible stamp is optional decoration. Government and enterprise systems frequently sign documents invisibly. This checker detects them regardless of visibility.

My PDF viewer shows no signature banner. Does that mean it's unsigned?

No. Many viewers — macOS Preview, most browser built-in viewers — simply don't surface digital signatures at all. Absence of a banner in those viewers tells you nothing. Check the file structurally (this tool) or open it in Acrobat's signature panel.

Someone drew their signature in a PDF app. Is that legally a signature?

It can qualify as a basic electronic signature in many jurisdictions (intent to sign matters more than form), but it carries none of the tamper-evidence or attribution of a digital signature — it's easy to forge, easy to repudiate, and impossible to verify. For anything contested or regulated, a certificate-based digital signature is the defensible option.

The PDF is signed — how do I check whether the signature is actually valid?

This checker verifies as it detects: you'll see the validity verdict, signer identity, certificate issuer, signing timestamp, and whether the document was modified after signing — the full verification, not just detection. For deeper detail on reading those results, see the Verify PDF Signature Online page.

Is this tool free?

Yes — free, no signup, no file-size games, and no upload: the PDF is analyzed entirely in your browser, which is exactly what you want for confidential signed documents.