You can add passwords to PDF files you create in the Create Assistant and prohibit or allow actions, such as printing, extracting content and editing. Choose a profile, then a setting in the Security drop-down list and click Advanced to specify passwords and permissions.
You can specify two passwords:
Open Password
Anyone providing this password can view the PDF it protects. This is sometimes called a user password. Further use of such a PDF depends on which permissions are set.
Permissions Password
Anyone providing this password can view the PDF and use it freely, regardless of permissions settings. They can also modify, remove or add permissions settings. This is sometimes called a master or owner password.
Before setting permissions you must supply and confirm a permissions password and specify the encryption strength: 40-bit, 128-bit or 256-bit. This determines which permissions are available. Make your settings and click OK.
Use New to name a new standard security control, make the desired settings and click OK. Use Delete to remove a security control. Use Default to return supplied controls to default values and remove user-defined controls.
Notes
Be sure to note the passwords you assign; without them you will not be able to re-open the PDF files you created. Successful PDF protection depends on good password distribution management.
Older PDF viewers may not support above 40-bit encryption. See About PDF Versions.
PDF Create usually creates 'Normal' PDF files. That means they can be viewed, printed, searched and modified in a PDF editor. But if some actions are prohibited and a user cannot supply the correct permissions password, the PDF may appear as image-only.