A visible handwritten signature alone does not prove that a PDF has a certificate-based digital signature. This desktop Reader guide checks a received PDF without changing the file or trust settings.
Step by step
- Keep the received original and open it directly in Reader. Do not substitute a newly printed PDF or screenshot for the signed original. For support, record the filename, Reader version and exact message.
- Open the Signatures panel and use its Options menu to validate signatures. The new interface also offers All tools → Use a certificate → Validate all signatures. Labels and positions may differ by interface.
- Read the result for every signature, not just the visible artwork. Open Signature Properties and the signer’s certificate. Check whether the identity and issuer match the expected sender and what Reader reports about trust and signed content.
- Distinguish the signer’s computer clock from a verified timestamp. An unverified timestamp does not provide the same confirmation. Do not change trust settings merely to remove a warning.
- For an unknown or invalid result, retain the message and contact the sender or responsible IT team through a known channel. Request the signed original again if needed. Do not disable certificate or revocation checks or broadly trust unfamiliar certificates.
Use the result carefully
Unknown does not automatically prove forgery, but it does not confirm a valid signature either. A successful technical check does not replace reviewing the document’s content or checking the signer’s authority for the transaction. Review every result in a multi-signature document; do not record unresolved findings as successful.