Adobe Acrobat support few security level:

1. No Security leaves the document unsecured, so there is no authentication required.
2. Password Security allows the document to be opened or manipulated by anyone who knows the required passwords.
3. Certificate Security identifies authorized users by the certificates they hold. When the document is secured, user certificates are assigned to a list identifying who's authorized to access the document.
4. Policy Server is a server-based security and authentication solution from Adobe. It counts real-time authentication among its many features.

Use Smart Card you need select certificate which use public key to encrypt PDF, then only person hold smart card will be able decrypt. This is the most secure way to protect you PDF (Ebook)

Permissions for the document can be set separately from access to the document

Here's a breakdown of the permissions settings:

1. Printing Allowed:
   • None: Prohibits all printing.
   • Low resolution (150 DPI): Allows printing, but only at a low resolution.
   • High resolution: Allows full printing privileges.
2. Changes Allowed:
   • None: Prohibits all changes to the document.
   • Inserting, deleting and rotating pages: Allows the insertion, deletion, and rotation of pages.
   • Filling in form fields and signing existing signature fields: Prohibits changes to the document, but allows the addition to the addition of form data, and digital signatures.
   • Commenting, filling in form fields and signing existing signature fields: Allows for the addition of comments, form data, and digital signatures.
   • Any except extracting pages: Allows all changes except for the extraction of pages.
3. Enable copying of text, images, and other content
   • Off: Prohibits readers selecting text or graphical objects, which would allow copying and pasting of content.
   • On: Enables text and graphics selection, allowing for the extraction of this content.
4. Enable text access for screen readers for the visually impaired
   • Off: Allows text to be accessed by screen-reading software for the visually impaired.
   • On: Allows text to be accessed by screen-reading software for the visually impaired.

By setup permissions with Smart Card you will have most bullet prove solution for your documents.

Secure PDF with Smart Card  Video Demo (Time 02:13)

Adobe view of secure PDF Video