Verify a signed document
Confirm that a completed PDF still matches its embedded cryptographic seal.
4 min read · Updated July 13, 2026
Every completed document carries a cryptographic seal using PAdES, CMS/PKCS #7, and an X.509 certificate. Verification checks whether the completed PDF still matches the byte ranges covered by that seal.
- The seal covers the whole document, so any later change breaks verification.
- A companion completion certificate records each signer's name, email, signed time, IP address, browser user agent, and the overall completion time.
- An RFC 3161 time-stamp token records trusted time evidence inside the PDF signature.
How to verify
- 1Open Signatures, then open the Verify a signed PDF tool.
- 2Choose the original completed PDF. Stoatify checks every embedded signature and reports the signature count and integrity result.
- 3Keep the original PDF and result with its completion certificate and surrounding agreement records.
What a successful result proves
A successful result means the embedded signature matches the PDF's signed byte ranges, so later alteration has not broken the seal. It does not by itself identify the human who used the signing link. Use the private-link, session, completion-certificate, and surrounding business evidence described in Signer evidence and legal effect.
Good to know
Stoatify seals documents with your organization's certificate. A self-signed organization certificate can appear as an unknown or untrusted issuer in an external PDF tool even when the tool confirms that the signed bytes are unchanged. Upload an organization certificate with the trust chain your workflow requires when external certificate trust matters.