in order to maintain a lot of time and energy into the PDF article, copyright, will not be any illegal use, the need for encryption of PDF articles, and method of using the password encryption easily cracked, encryption using digital certificates can be more effectively protected PDF documents, digital certificates can be delegated to one or more of the certificate user. Windows digital certificates or Adobe Reader can be generated in Adobe Acrobt, Adobe Reader 7.0 below as an example to illustrate the generation of Windows digital certificates and export, Adobe Acrobat is similar to the generation method, only out of "security settings" menu at the location different.

1, open Adobe Reader 7.0.