You can obtain a digital certificate either by purchasing one or by using the self-sign method.
Purchase one from a certificate authority, such as Verisign, and save it to your computer. This method is recommended because it is easier to verify (and therefore trust) the authenticity of the certificate that you purchase. Next, use Microsoft Internet Explorer 7 or later to create a PFX file based on the certificate you purchased. See Creating PFX Files.
Create a self-signed certificate using a software program, such as Adobe Acrobat, Adobe Reader, OpenSSL, or OSDT. This method is less preferred because anyone can create a self-signed certificate. Therefore, it is more difficult to verify and trust the authenticity of the certificate.
Typically, when you create a self-signed certificate using a software program, the program saves the certificate as part of a PFX file. If this is the case, you do not need to create another PFX file (as described in Creating PFX Files).
To create a self-signed certificate using Adobe Reader:
Open Adobe Reader.
From the Document menu, click Security Settings.
Select Digital IDs on the left.
On the toolbar, click Add ID.
Follow the steps in the Add Digital ID wizard. For assistance, refer to the documentation provided with Adobe Reader.
When prompted, save your self-signed certificate as part of a PFX file to an accessible location on your computer.
After you create your self-signed certificate as part of a PFX file, you can use the PFX file to sign PDF documents by registering it with BI Publisher. See Implementing a Digital Signature.