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Acrobat 9 Family of Products
Authoring Signable Documents
Security Feature User Guide
Making a Field a Required Part of a Workflow 63
Preventing users from changing form data after the document has been signed.
To automatically lock one or more fields after signing:
1. Create a new signature field.
Note:
For existing fields, place them field in edit mode by selecting
Forms > Add or Edit Fields
and then double click on them OR right click and choose
Properties
.
2. Display the Signed tab.
Figure 52 Signature field: Signing properties
3. Choose
Mark as read only
.
When a field with field locking is signed, both a normal document signature and an object hash of the
locked fields are produced and included in the document. When the signature is validated, the viewing
application validates the bytes of the PDF file AND compares the object hash in the signature to the
object hash from the objects in memory. This allows the application to detect prohibited, changes.
4. Use the drop-down list to select from the following:
All fields
: All signature fields will be read only after signing.
All fields except these
: All signature fields except those specified will be read only after signing.
Choose
Pick
and select the field to exclude.
Just these fields
: Only the specified signature fields will be read only after signing. Choose
Pick
and
select the field to include.
5. Choose
Close
.
4.4.3 Making a Field a Required Part of a Workflow
Certain workflows may require a signature. For example, after a signature field is signed, form fields may be
prepopulated or additional fields may appear. It is also common for form designers to require signing
before the document can be emailed or submitted to a server for processing.
To require a signature:
1. Place the field in edit mode by selecting
Forms > Add or Edit Fields
.