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Seal the bytes, not just the page

Create or verify a cryptographic proof for an exact PDF. Your PDF is never rewritten or uploaded. The proof is a separate file, not an embedded certificate signature recognized by PDF readers.

Personal seal controls

Up to 20 MiB. Finish all edits before sealing. This tool checks a PDF header and exact bytes, not document structure or whether its contents are safe.

Your signing key

Create a reusable key, or unlock one from your password-encrypted backup. No key or password is saved in browser storage. Use a long, unique passphrase; there is no recovery.

Use at least 12 characters. A long, unique passphrase is safer.

Enter the same password again.

Selecting Create proof signs this statement: "I approve the contents of this PDF." No trusted timestamp or identity verification is provided.

Discard this work?

This clears PDFs, proofs, passwords and the unlocked key from this tab. Save your encrypted key and proof first. Downloaded files are unchanged; losing your key or password cannot be recovered.

How to seal or verify a PDF

  1. Choose a final PDF, then create a key with a long passphrase or unlock an encrypted key backup.
  2. Save the encrypted key backup, create a proof, and download it. Share the unchanged PDF and proof together.
  3. To verify, choose the PDF and proof, optionally supply a separately trusted key fingerprint, and select Verify proof.

ECDSA P-256 signs the SHA-256 document digest, byte count, approval statement, random nonce and public key in a versioned record. Proofs are detached, not PDF-reader certificate signatures. Keys and passwords are never automatically persisted. A valid proof alone does not verify identity, legal validity or signing time; independently confirm the signer fingerprint. PDF contents are not parsed or assessed for safety.

PDFBurrow processes your documents in this browser, without uploading them.

Files stay in this tab's memory. Refreshing or closing the tab loses your work; original files and downloaded copies are unchanged. Browser leave warnings are best effort.

Experimental build: provisional workload limits are enforced, but are not device-tested safety guarantees. Complex files may still exhaust browser memory. Offline use is not promised.

Source codePrivacyLicenses/noticesWorkload limits

These links open in a new tab without discarding your work.

Discard this work?

Changing tools or returning Home clears inputs, settings, outputs and unlocked signing keys from this tab. Save any encrypted key backup and proof first. Original files and downloaded copies are unchanged.