Check the digital signatures of a PDF
Find out if a signed PDF is still as it was signed. The check runs in your browser.
- Your files are never uploaded
- Processed on your device
- Works offline
- Free, no sign-up
Drop your PDF files here
PDF files · up to 20 files, 500 MB each
or paste with Ctrl+VLive preview
Settings
Checks signatures attached to PDF form fields or certification permissions. Certificate trust and revocation are not checked. Encrypted PDFs and unsupported signature formats need a PDF reader.
Nothing is uploadedHow it works
Add a signed PDF
Contracts, certificates or forms.
Read the result
Each signature, its signer and whether the file changed.
Compare the signer
Make sure the name is who you expect.
What is checked
The signature maths, using your browser's WebCrypto: if the signed part of the file was changed, the signature is not valid. Also who the certificate belongs to, who issued it and when it is valid.
Whether the issuer is trusted, and whether a certificate was revoked, needs online services. This tool works offline, so it says so instead of guessing.
Private
Your file is processed inside your browser with pkijs (BSD-3-Clause) and your browser's WebCrypto. It is never uploaded, and nothing is saved after you close the page.
Questions
Are my files uploaded?
No. The tool runs inside your browser, so your files are opened and changed on your own device. They are never sent to us or to anyone else.
Why does it say trust is not checked?
Trust lists and revocation checks are online services. To keep your file private and work offline, they are not used.
Is it free?
Yes. Free to use, with no sign-up, no watermark and no daily limits.
Related tools
More free tools that run on your device. No uploads