Operation Manual

230
USING ACROBAT X STANDARD
Digital signatures
Last updated 10/11/2011
Signature types
A document can contain certification signatures, approval signatures, or both. The signature type you need depends
on the intent of both the author and the signer. Signature types include the following:
Certification signature A certification signature provides a higher level of document control than an approval
signature. Because it must be the first signature in a document, certification menu options are disabled if another
signature is already present. In addition, you can control the types of changes other people may make.
Approval signature An Approval signature is a digital signature applied to a document that is not a certification
signature. All signatures other than certification signatures are classified as Approval signatures.
Both certification and approval signatures comply with data protection standards specified by the European
Telecommunications Standards Institute (ETSI). In addition, both signature types comply with the PDF Advanced
Electronic Signature (PAdES) standard. Acrobat and Reader provide an option to change the default signing format
to a CAdES format. To view this option, go to Edit > Preferences > Security > Advanced Preferences > Creation, and
expand Default Signature Signing Format list. This option is compliant with Part 3 of the PAdES standard. The
timestamp capability and native support for long-term validation of signatures (introduced in Acrobat 9.1) is in
compliance with Part 4 of the PAdES standard. The default signing format, when set up accordingly, is compliant with
Part 2 of the PAdES standard.
Sign a PDF
You can sign a PDF to indicate your approval using either a digital signature or ink signature. Digital signatures can
be used to sign a PDF multiple times and by different persons. When you sign a document, your digital signature
appears in the signature field. The appearance of the signature depends on options you choose. The actual information
for your digital signature is embedded in the PDF.
In Acrobat, the first person to sign a document can add a certifying signature to restrict changes to the document.
Note: To allow Reader users to sign documents using either type of signature, choose File > Save As > Reader Extended
PDF in Acrobat. Then, choose an option from the list.
Sign a PDF—Quick steps
Signing is essentially a straightforward process. It can be complicated by special requirements, such as creating
different signatures for different roles and adding timestamps. But to create an uncomplicated signature, follow these
steps.
1 Complete your edits before you sign. Changes made to the document after it is signed can invalidate the signature.
2 Get a digital ID from your own organization, buy a digital ID (see the Adobe website for security partners), or create
a self-signed one. See
“Create a self-signed digital ID” on page 216. You can’t sign a PDF without a digital id.
3 Drag your pointer to create a space for the signature.
4 Follow the onscreen prompts to finish signing the PDF.
Sign with a new digital ID
1 Open the PDF and choose Tools > Sign & Certify > Sign Document. If you don't see the Sign & Certify panel, see
the instructions for adding panels at
“Task panes” on page 8.
2 If a dialog box appears, read the information and then click OK.
3 Drag your pointer to create a space for the signature.
4 Select A New Digital ID I Want To Create Now from the Add Digital ID dialog box.