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Verify PDF Signatures
Check digital signatures: was the file changed, who signed it, certificate chain and timestamps.
Free, no uploads, no sign-up. Runs 100% in your browser.
How Verify PDF Signatures works
Each signature dictionary is read with pdf-lib. The signed byte ranges are hashed with WebCrypto and compared to the CMS message digest, the signature is verified against the signer's public key (RSA, RSA-PSS or ECDSA), the certificate chain is checked link by link, and embedded RFC 3161 timestamps are decoded.
Input: PDF.
How to use Verify PDF Signatures
- Drop your PDF onto the Verify PDF Signatures area, or click to choose it.
- Wait a moment while page thumbnails render locally.
- Choose the pages and options you need. Previews update as you go.
- Press the main action button and download the finished PDF.
Tips
- Encrypted PDFs must be unlocked first with Unlock PDF.
- Large scanned PDFs are mostly images. Compress PDF shrinks them the most.
- Your original file is never modified; you always download a new copy.
Verify PDF Signatures FAQ
- Are my files uploaded?
- No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
- Is it free? Are there limits or watermarks?
- Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
- Does it work offline?
- Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.
Related tools
- Digital Signature (Certificate): Sign a PDF with your .p12 or .pfx certificate, visibly or invisibly, without uploading it.
- PDF Inspector: See page sizes, fonts and whether they are embedded, images, scripts, version, encryption and word counts.
- Merge PDF: Combine multiple PDFs into one ordered document with drag-and-drop sorting.
- Split PDF: Split by ranges, every N pages, or extract each page into a ZIP.