When Digital Signatures are validated, an icon appears in the document message bar to indicate the signature status. Additional status details appear in the Signatures panel and in the Signature Properties dialog box. Signature validity is determined by checking the authenticity of the signature’s digital ID certificate status and document integrity:
- Authenticity verification confirms that the signer's certificate or its parent certificates exist in the validator’s list of trusted identities. It also confirms whether the signing certificate is valid based on the user's Acrobat or Reader configuration.
- Document integrity verification confirms whether the signed content changed after it was signed. If content changes, document integrity verification confirms whether the content changed in a manner permitted by the signer.
For more information, see “Setting up digital signature validation” at: https://helpx.adobe.com/acrobat/using/validating-digital-signatures.html
