Adobe Acrobat 8 3D - Manual (Page 291)

284 ADOBE ACROBAT 3D VERSION 8
User Guide
See also
“Validate a timestamp certificate” on page 285
“Sign in Preview Document mode” on page 280
“View previous versions of a signed document” on page 286
Set signature verification preferences
Before you open signed documents, set your preferences to optimize Acrobat for validating signatures.
1 Choose Edit > Preferences (Windows) or Acrobat > Preferences (Mac OS), and select Security on the left.
2 To automatically validate all signatures in a PDF when you open the document, select Verify Signatures When The
Document Is Opened. This option is enabled by default.
3 Click Advanced Preferences, and then click the Verification tab.
4 Choose the following options:
When Verifying These options specify methods that determine which plug-in to choose when verifying a signature.
The appropriate plug-in is often selected automatically. Contact your system administrator about specific plug-in
requirements for validating signatures.
Require That Certificate Revocation Checking Be Done Whenever Possible During Signature Verification Select this
option to require certificates to be checked against a list of excluded certificates during validation. If this option isn’t
selected, the revocation status for approval signatures is ignored. The revocation status is always checked for certi­
fying signatures.
Verify Signatures Using Select an option to determine whether the time that appears in the digital signature reflects
the time the signature was validated (Current Time), the time set by the default timestamp server specified in the
Security Settings, or the time the signature was created.
Hide Signature Field Validity Icon When Signature Is Valid Hides the signature status if the signature is valid, even if
the document has changed since it’s been signed (indicated by a green check mark and caution triangle icon).
5 Click the Windows Integration tab, and specify whether you can import identities from the Windows Certificates
feature into the list of trusted identities. In addition, specify whether to trust all root certificates in the Windows
Certificates feature when validating signatures and when validating certified documents. Be aware that selecting
these options might compromise security.
Signatures panel overview
The Signatures panel lists all the signatures in the current document. Each signature has an icon identifying its verifi­
cation status. Verification details are listed beneath each signature and can be viewed by expanding the signature, or
by making selections from the Options menu in the Security panel.