Security

Use Acrobat's security to protect your files from unwanted access. When you create a PDF file, it isn't protected until you set the protection. Security commands are located in a submenu of the Document menu. Under the Security submenu, choose Secure This Document, where you can then choose from different security policies (see Figure 10.21).

Figure 10.21. Choosing a security policy.

Restrict Opening and Editing

When you choose Restrict Opening and Editing, the Password SecuritySettings dialog box opens. Within this dialog box, you can set the Compatibility version of Acrobat. The lower the version is, the lower the encryption level is. The higher the version of Acrobat it is, the higher the encryption level is.

You can check the box to require a password to open the document. When you choose this option, you'll be asked for a password to enter. If you choose this option, you always have to use a password to open the document.

Permissions options include using a password to restrict printing and editing of the PDF and its security settings. With the Permissions check box, you set the password and choose whether you allow any printing, low-resolution printing, or high- resolution printing. You also set whether changes will be allowed, including Inserting, Deleting, and Rotating Pages; Filling in Form Fields and Signing; Commenting, Filling in Form Fields, and Signing; and Any Except Extracting Pages (see Figure 10.22). Other check boxes include Enable Copying of Text, Images, and Other Content; Enable Text Access for Screen Reader Devices for the Visually Impaired; and Enable Plain-Text Metadata.

Figure 10.22. Specifying a Permissions password.

You have three tries to open a password-protected PDF file. After three tries, the document closes, and you have to reopen it to try the password again.

Encrypt for Certain Identities

If you choose the option Encrypt for Certain Identities Using Certificates, the Document SecurityDigital ID Selection dialog box launches. Select the Digital ID file from the pop-up menu and enter the User Password. Other choices are Find Your Digital ID File and Create a New Digital ID File.

Display Restrictions and Security

Choosing the Show Security Settings for This Document choice in the Security submenu launches the Document Properties dialog box. In this dialog box, you can set the security method (choose No Security, Password Security, or Certificate Security). If you choose to change the security method by clicking the Change Settings button, you get the Permissions Options dialog box, as you did with the Restrict Opening and Editing function. The Document Properties dialog box displays the security settings and shows the details of the PDF document (see Figure 10.23).

Figure 10.23. The Document Properties dialog box displaying the security and restrictions settings.

Digital Signatures

More than ever, people want to use digital signatures to replace hand signatures. Using a digital signature saves a ton of time and money because you don't have to ship documents back and forth. A digital signature can be an actual handwritten name, text, or a graphic symbol. When you have a digital signature, you can verify that the signature is authentic.

Acrobat has a Self-Sign Security feature. This program handles the digital signatures. Set up a signature for signing by choosing Advanced, Security Settings, and then click on the Add ID button (see Figure 10.24).

Figure 10.24. Adding a new ID in the Security Settings dialog box.

After you set up your profile, you can edit the profile to set how your signature will be used in a PDF file.

Create a Digital Signature

Now that you have learned how to create a profile, you'll need to add your actual signature or image for the digital signature. First you'll need to scan in your actual signature or use any image and save it as a PDF file. In Acrobat's Preferences dialog box, you select Digital Signatures from the list on the left. Click the New button to add your scanned signature. This launches the Configure Signature Appearance dialog box. In this dialog box, enter a Title; under Configure Graphic, choose the PDF File button. In the Select Picture dialog box, click the Browse button, choose your scanned PDF file, and then click OK. In the Select Picture dialog box, you'll see a small preview of your signature. Click OK three times while clicking your heels together, and you have a saved digital signature.

Digitally Sign Your Document

The signature you have saved can now be applied to any PDF document.

Did you Know?

To sign your PDF document with your digital signature, click the Signatures tab on the left side of the window (housed with Pages, Layers, and Bookmarks). Under the Options menu in the Signatures pane, choose Create a Blank Signature Field, and then drag out a box to hold your signature. The Digital Signature Properties dialog box comes up. Select the style for the box. Click Close. Then choose Sign Signature Field from the Options area of the Signature window. Click the Continue Signing button after you have read the alert. This brings up the Apply Signature to Document dialog box. Enter your password and then click the Sign and Save button. Your digital signature appears in the box you dragged out (see Figure 10.25).

Figure 10.25. A digital signature on a PDF document.

Certified PDF

After you digitally sign a document, you might want to certify the PDF document. Doing this lets you exercise some control over the editing of the file. To certify your PDF, follow these steps:

1.	Choose Save As Certified Document under the File menu. A Save As Certified Document dialog box then comes up.
2.	In this dialog box, you are told that you need a digital ID to certify the document. You can get a digital ID from Adobe Partner, or click OK if you already have a digital ID. After you click OK, you set the allowable actions.
3.	Choose from the following: Disallow Any Changes to the Document, Only Allow Form Fill-In Actions on This Document, or Only Allow Commenting and Form Fill-In Actions on This Document. By the Way These take effect only after you save and close the document. It is also a good idea to lock the certifying signature so that it can't be cleared or deleted by anyone.
4.	Click the Next button. A warning dialog box comes up, alerting you of any potential problems or suggestions.
5.	Click the Next button. Then choose the visibility of the certification (Show Certification on Document or Do Not Show Certification on Document).
6.	Drag out the area where you want the certification to appear on your document.
7.	Click OK and, using your mouse, indicate the area on your document.
8.	Choose the digital ID in the next dialog box.
9.	Enter your password in the Save As Certified DocumentSign dialog box. From the pop-up menu, choose a reason why you are signing.
10.	Click Sign and Save As (or choose Sign and Save, and you'll overwrite the original document).
11.	Enter a name and location, and click Save.