Adobe ACROBAT READER 7.0, Manual, Page: 147 / 262

Validating signatures
When you validate a signature, you verify the signer's identity and assess any changes
made after the document was signed. For an identity to be valid, the signer's certificate, or
one of its parent certificates that was used to issue the signer's certificate, must be in your
list of trusted identities, and it must not have expired or been revoked. (See
Building a list
of trusted identities .)
When you open a document, its signatures are validated automatically, unless you turn off
a preference setting. The verification status appears on the document page and in the
Signatures tab. If you don't have the signer's certificate, the signature validity is unknown.
Third-party signature handlers may verify identities using other methods. You can specify
whether document-specific settings or default settings are used for verifying documents,
check to see if certification has been revoked, add time stamps to signatures, and change
other validation settings. (See
Setting Digital Signature preferences .)
To validate a signature:
1. Open the PDF document containing the signature.
2. In the signature field or in the Signatures tab, check whether the warning sign icon
appears next to the signature. If this icon appears, the document may have been modified
after it was signed.
3. Select the signature in the Signatures tab, and then choose Validate Signature from the
Options menu. The Signature Validation Status describes the signature status.
4. Click Legal Notice to learn more about the legal restrictions of this signature, and then
click OK.
5. If the status is unknown, click Signature Properties, click the Signer tab, and then click
Show Certificate to view the details of the certificate. If you're working with self-signed
digital IDs, confirm that the certificate details are valid. (See
Checking information on
certificates .)
If the document has more than one signature, you can view a copy of the signed version in
a separate document window. (See
Viewing previous versions of a signed document .)
Related Subtopics:
Viewing previous versions of a signed document
Setting Digital Signature preferences