TIP 143: Certifying a Document
One way to maintain a PDF document as a legally correct document is to certify it. When you certify a PDF document, you're certifying the contents and specifying the types of changes allowed that maintain the certification. For example, a form may be certified and allow the user to fill in the fields; however, if the user tries to delete or replace pages, the document will no longer be certified. Certification is one way of using Digital IDs. Make sure you have finished modifying your document before certifying it. Otherwise, changes you make may corrupt the signature.
Certify It or Sign It?
Decide when you need to certify a document and when you need to sign it. If you create a lot of documents for secure distribution, you may want to certify each document as you generate it. However, be aware of the restrictions added to a document when you certify it. If you intend any of your recipients to make changes, such as additions or deletions, sign it and specify a reason, such as "I am the author" rather than certifying it (see Tip 144). |
Choose File > Save as Certified Document and follow the wizard-like screens, starting with the introduction. To use a third-party security company, click Get Digital ID from Adobe Partner on the introductory screen; otherwise, proceed through the dialogs defining the type of certification and what actions you want to allow your users to take. You also define the visual characteristics of the signature, including its location on the page, and whether or not it is visible. Here are some tips for making the certification process smoother: In the Choose Allowable Actions dialog (Figure 143a), specify the rights you want to grant the user. The pull-down list offers three options: you can prevent any changes from being made, allow users to fill out forms, or allow users to both comment and fill out forms. Also specify if you want to lock the certifying signature.
Figure 143a. Decide what actions you want your readers to access when certifying a document.
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The Warnings dialog describes document features that may compromise the integrity of the document. In Figure 143b, for example, the warning mentions the use of comments, which were allowed in the previous dialog.
Figure 143b. Acrobat informs you of any potential issues that can occur as a result of the rights you grant to your users.
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Signing and Saving
Here are some tips to keep in mind as you incorporate digital signatures as part of your Acrobat workflow: If you aren't completely sure the document is finished, don't click Sign and Save; instead, click Sign and Save As. Save the document with another name, and preserve the original unsigned in case you decide to make changes before distributing the document. Don't try to save the document with another name after the certification is complete. Saving is not allowed at this point. You cannot encrypt a document if it already contains signatures. If you want to share a document that has been signed, either use an unsigned copy or remove the signatures. To delete the signatures, click the Options menu in the Signatures pane and click Clear All Signature Fields. In order to use a document in a review process, you should certify the document to allow commenting and form fill-in.
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In the Save as Certified Document dialog, choose options for the actual signature used in the certification process (Figure 143c). Click Show/Hide Options to toggle additional options on the dialog so you can choose the signature appearance, reason for signing, and other options (see the previous tip). If you wish, you can click New on this dialog and create a new appearance.
Figure 143c. Select a reason for signing and a signature appearance to use for the certification process.
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Once a document is certified, you can find out certification information from the document itself. When the document is opened, you'll see a Certified Document icon at the left of the status bar. Hold your pointer over the icon, and a message appears telling you that the document is certified. Click the certified document icon to open a dialog that describes the document's status. The dialog explains that the document has special security features, and contains buttons for accessing legal and signature information.
Certification Tips
The document certification process can be intricate. Smooth your way by keeping these ideas in mind: A document that can be modified is potentially dangerous. The document is said to have "malicious potential." In the Signatures pane, information about the potential problems is included with other signature information. Plan as you work your way through the Certification dialogs. You can't go back and change any options in previous dialogs. If you need to make changes before you have finished the certification process, click Cancel on any dialog and start over.
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You can also find information about the document's status in the Signature pane. Click the Signatures tab on the Navigation tabs to open the pane (Figure 4d). Information about the document, its status, signature dates, encryption method, and so on are listed in the pane.
Figure 143d. The Signatures pane describes all the information you selected in the certification process; the stamp applied to the document at the right of the figure shows the custom appearance, as well as the Certification symbol.
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