Operation Manual

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Electronic signatures
Last updated 4/7/2015
If all the elements of the certificate chain are available, the information is added to the PDF automatically. If a
timestamp server has been configured, the timestamp is also added.
Add verification information after signing
In some workflows, signature validation information is unavailable at signing, but can be obtained later. For example,
a company official may sign a contract using a laptop while traveling by air. The computer cannot communicate with
the Internet to obtain timestamping and revocation information to add to the signature. When Internet access is
available later, anyone who validates the signature can add this information to the PDF. All subsequent signature
validations can also use this information.
1 Ensure that your computer can connect to the appropriate network resources, and then right-click the signature in
the PDF.
2 Choose Add Verification Information.
Information and methods used to include this long term validation (LTV) information in the PDF comply with Part 4
of the ETSI 102 778 PDF Advanced Electronic Signatures (PAdES) standard. For more information, see
blogs.adobe.com/security/2009/09/eliminating_the_penone_step_at.html. The command is unavailable if the
signature is invalid, or is signed with a self-signed certificate. The command is also unavailable in case the verification
time equals the current time.
More Help topics
Certificate-based signatures
Digital IDs
Signing PDFs
Manage trusted identities
Validating certificate-based signatures
Set your verification preferences in advance. This helps ensure that certificate-based signatures are valid when you open
a PDF and verification details appear with the signature. See
Set signature verification preferencesfor details.
When certificate-based 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.
Setting up validation for certificate-based signatures
When you receive a signed document, you may want to validate its signature(s) to verify the signer and the signed
content. Depending on how you have configured your application, validation may occur automatically. 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.