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PPDF123

Remove Digital Signatures From a PDF

Remove Certificate Signature deletes the digital signature fields from a PDF, together with the certification lock that blocks edits, so the file no longer reports as signed. Ordinary form fields are kept.

Drag and drop files here, or click to choose

Accepts PDF · up to 500.0 MB per file · up to 20 files at once

You can also paste a file with Ctrl/Cmd+V, or from the clipboard menu.

Remove Certificate Signature strips the digital signatures out of a PDF so a file that was signed or certified no longer reports as signed. The handler walks `/AcroForm/Fields`, deletes every field whose `FT` is `Sig`, drops the matching `/V` signature dictionaries and their widget annotations, then clears `/SigFlags`.

When at least one signature field is found, it also removes the catalog's `/Perms` entry, including `/DocMDP`, the certification that locks a document against changes, and the `/DSS` document security store. Ordinary form fields (text boxes, checkboxes, radio groups) are untouched. A file with no signature field is returned unchanged.

With `/Perms/DocMDP` gone, an editor that refused to modify a certified file will accept changes again. Re-signing after this creates a brand new signature; nothing from the old one carries over.

Password-protected files are unlocked for you on this page once you enter the password; API callers run Unlock first. To inspect a signature without changing the file, use Validate Signature.

Features

  • Removes `FT=Sig` fields, their `/V` values and their widget annotations
  • Clears `/SigFlags`, the catalog `/Perms` entry (DocMDP) and `/DSS`
  • Keeps every non-signature form field
  • Anonymous API at /api/v1/security/remove-cert-sign

When to use this tool

  • Clear a signature from a draft so you can edit and re-sign it
  • Remove a certification lock that blocks form edits
  • Produce an unsigned fixture for a QA workflow

How do I remove a digital signature from a PDF?

  1. Upload the signed or certified PDF.
  2. Click Process. There are no options; every signature in the file is removed.
  3. Download the unsigned PDF.
  4. Run Validate Signature on the download if you want to confirm no signature dictionaries remain.

Limits and edge cases

  • Destructive: the cryptographic proof is gone for good
  • A file with no signature field is returned unchanged, even if it carries a certification entry
  • Does not unlock passwords or strip JavaScript
  • Password-protected files need the password; API callers run Unlock first
  • Upload limit on this website: 500 MB per file, sent in chunks above about 95 MB. A single direct API request body is capped at 100 MB.

Examples

  • A certified contract downloads with no signature field at all, and editing it is allowed again
  • Validate Signature on the download returns an empty list

Privacy for this tool

Files are uploaded over HTTPS, processed in memory or a short-lived temporary directory on our servers, and deleted when your result is ready. We do not keep copies for later browsing, training, or advertising profiles. See the Privacy Policy for retention details and AdSense cookie disclosures.

Frequently asked questions

Will a viewer still show the old signature?
No. The field, its value dictionary and its page annotation are all removed, so the viewer has nothing left to display.
Is the document still certified?
Not once a signature field has been removed: `/Perms` and its `/DocMDP` entry are deleted, so the file is no longer locked against changes.
Can I verify a signature instead?
Yes — Validate Signature reports the signatures in a file without changing it.
Does this unlock password encryption?
No. Use Unlock for passwords.
Can I get the original signature back?
No. Removal is destructive; keep your own copy of the signed original.

Last updated:

Call this from code

Every tool on this site is a plain REST endpoint - no account or API key needed for anonymous use. Built for AI agents and developers as much as for browsers.

curl -X POST "https://pdf123.xyz/api/v1/security/remove-cert-sign" \
  -F "[email protected]" \
  -o output.pdf

Also available as an MCP tool for agent clients that speak Model Context Protocol (JSON-RPC 2.0 over POST /mcp). Full API reference

Use it from an AI agent

Skill

Claude Code, Codex, Cursor and other AI agents can run Remove Certificate Signature for you with this skill: /skills/pdf123-remove-cert-sign.md

All agent skills

Files are used only for this processing job and deleted automatically afterward.