You don’t need a pen to sign an electronic document. Security features in Digi-Seal™ and Adobe® Acrobat® 7+ let you sign documents, whether to simply show approval or to control access and modifications to the documents you distribute.
To digitally sign a document, you design the appearance of your signature, decide where you’re going to sign, and obtain or create a digital ID, which allows others to validate your signature.
To limit access to a document, you must have digital IDs for the people you want to give access to.
Choose Edit > Preferences (Windows) or Acrobat > Preferences (Mac OS), and then choose Security. Click New in the Digital Signatures section of the panel to create a new signature appearance. Choose the items that you want to appear with your signature, including the date when you signed, the reason that you signed, the Acrobat logo, and other information. The preview changes as you make your selections. If you want to include a graphic, select Imported Graphic, and then click File and select the PDF file that you want to include. Give the signature appearance a title, and then click OK.
You can create multiple signature appearances, each for a different purpose. For example, you may want to use one signature appearance for signing contracts and a different signature appearance for signing correspondence.
2. Choose to sign the document.
In Acrobat, open the PDF file that you want to sign. Choose Document > Digital Signatures > Sign This Document. If the document has not been certified, Acrobat displays an alert dialog box. Click Continue Signing to sign the document.
You may also choose to certify the document. When you certify a document, you attest to its contents and specify what changes may be made to the document. If other changes are made after you sign, the document becomes uncertified.
3. Select the signature field.
If a signature field already exists on the document, choose Sign an Existing Signature Field. When you click OK, Acrobat scrolls to the signature field; click the signature field with the Hand tool to select it.
If no signature field exists, choose Create A New Signature Field To Sign. Acrobat displays an information screen; when you click OK, you can draw the signature field on the page.
Alternatively, you can create an invisible signature. Invisible signatures do not appear on the page in the document pane; they are visible only on the Signatures tab.
4. Select a digital ID.
Select or obtain a digital ID created by another company. Alternatively, you can create a self-signed digital ID.
A digital ID contains information in a certificate, which can be shared with others and is used by them to validate your signature. Third-party digital IDs can be verified by other companies and are therefore more secure than
self-signed digital IDs.
5. Apply the signature.
Enter any additional information, such as your location or your reason for signing, and then sign and save the document.
You must save the document in order to sign it. Choose Sign and Save to save the document with its original name. Choose Sign And Save As to save the document with a different name.
6. Obtain other digital ID files.
If you want to restrict access to the PDF file, then you need digital ID files for the people who require access. Choose Advanced > Manage Digital IDs > Trusted Identities, and then click Request Contact. Type your name and e-mail address, and click Next. To send an e-mail message, type the e-mail address, edit the message, and click Send. If necessary, finish the e-mail message in your e-mail client application. When you receive the digital ID file, open the attachment, choose Set Contact Trust, and then click Import.
Once you have added someone’s digital ID to your trusted identities, it remains there until you delete it. You can use it to validate that person’s signature or to provide access rights to PDF files in the future.
7. Set access rights.
Choose Document > Security > Show Security Settings For This Document. From the Security Method menu, choose Certificate Security. Choose which document components you want to encrypt and click Next. Select a digital ID for yourself so that you can open the document later. Then select the digital IDs for the people to whom you want to grant access. Select each digital ID and click Permissions to set restrictions on printing or making changes for that individual. Click Next. Review the settings; if you want to change any, click Back. Otherwise, click Finish. Save the file to preserve the security settings.
When you encrypt a PDF file, you restrict access to the document to a specific list of recipients. You can also restrict the recipients’ ability to edit, copy, or print the file.
Note that you can also use more than one digital certificate to sign a document. If you want to do this, repeat steps from 2 to 5 the same number of times as the number of digital certificates used.