Verify signatures
See whether the signatures in a PDF are intact, and what changed after signing.
Intact means the bytes a signature covers have not changed since it was made. It does not say who signed. wtfpdf keeps no list of trusted authorities, so it cannot tell whether a certificate belongs to the person or company it names. Everything is checked on your device, and nothing is fetched from the network.
Drop a PDF here
Your files stay on this device. Nothing is uploaded.
How to check a PDF signature
- Drop your signed PDF on the box above, or choose it from your device.
- Read the panel for each signature, newest first. Its status shows whether the signed bytes are intact.
- Check what each signature covers, and the list of changes made after signing.
- Select Show on page to see where a visible signature sits in the document.
Private by design
Your file is never uploaded. The PDF engine runs in this browser tab and the result is saved straight to your device. You can check: open your browser’s network panel while you work and you will see no request carrying your file. After your first visit it even works offline. How wtfpdf works
Questions
How do I check if a PDF signature is valid?
Open the PDF here. Each signature shows as Intact, Changed after signing, Altered, Cannot check, Unsupported or Malformed. Intact means the bytes it covers have not changed since signing.
Does wtfpdf tell me who signed the PDF?
It shows the names in the signer’s certificate, but it does not verify them. wtfpdf keeps no list of trusted authorities, so it cannot tell whether a certificate belongs to the person or company it names.
Can I see what changed after a PDF was signed?
Yes. wtfpdf lists changes made after signing, such as form fields filled in, comments added or new signatures. It also says whether the signature’s rules allow them.
Is my signed PDF uploaded?
No. Everything is checked on your device, and nothing is fetched from the network. Revocation data and timestamps are read only from the file itself.
Does it check certificate revocation and timestamps?
Yes, when the file carries them. wtfpdf checks embedded revocation data and timestamps, but never fetches any from the internet.
Does verifying change my PDF?
No. Verify only reads the file. It changes nothing and offers no download.